navigation acronyms, abbreviations and definitions - International ...

NAVIGATION 

ACRONYMS, ABBREVIATIONS 

AND DEFINITIONS 

Collected by David Broughton 

The Glossary may be reproduced freely, but please inform the Royal Institute of 

Navigation of any amendments or additions via e-mail (anglia@rin.org.uk). 

‘ minute (= 1º/60) 

112 European emergency phone number (= 911 in US, 999 in UK) 

1st4sport 

Qualifications 

Awarding body of the NCF 

2-AFC two-alternative forced-choice (procedure used in animal studies) 

2dRMS twice distance root-mean-square 

Twice the root-mean-square of the radial distances from the true 

position to the observed positions obtained from a number of trials. 

Should contain 95% of observed positions. 

2SOPS 2nd Space Operations Sqn (of 50th Space Wing)(USAF) 

Exercises command and control of GPS satellite constellation. 

3DNC Three-dimensional digital navigational chart 

3G third generation (of mobile phone technology or telematics) 

There is also 2G, 2.5G and 4G for phones. 

3GPP 3G Partnership Project 

A collaboration between telecommunications associations, to make a 

globally applicable 3G mobile phone system specification. 

3GT 3rd Generation Telematics (ERTICO and OSGi project) 

3PL third-party logistics 

802.11 a wireless interconnection standard with a range of 50 metres 

Also known as WiFi. An IEEE standard. 

911 US emergency phone number (= 112 in Europe, 999 in UK) 

a atto (SI unit multiplier of 10 -18 ) 

a semi-major axis of ellipse (for WGS-84 = 6,378,137 m) 

A-band NATO radar band 0-250 MHz = > 1.2 m 

A-GNSS (AGNSS) Assisted GNSS 

A-GPS (AGPS) Assisted GPS 

A-NPA Advance Notice of Proposed Amendment (EU JAA) 

A-NPRM Advance Notice of Proposed Rulemaking (FAA, FCC etc) 

A-S anti-spoofing 

In GPS the use of encryption to prevent a P-Code receiver locking to a 

bogus P-Code transmission. 

A-SMGCS Advanced Surface Movement Guidance & Control System 

A/A air-to-air 

1 

March 2012

A/D (a/d) aerodrome 

A/D analogue-to-digital 

A/G air-to-ground 

A/J anti-jamming 

A/P autopilot 

A1A CW telegraphy (eg morse code) keying the transmitted signal 

A2A CW telegraphy (eg morse code) keying the modulation only 

AA Aircraft Address (unique ident 24 bit ident number - ICAO Mode S) 

AAA airfield avoidance area 

AAAF Association Aéronautique et Astronautique de France 

AAAS American Association for the Advancement of Science 

AAC aeronautical/airline administrative communications 

AAC Army Air Corps 

AAD Additional Airworthiness Directive 

AAD assigned altitude deviation 

aae above aerodrome elevation 

AAF Army Air Field (US) 

AAI Airports Authority of India 

AAI angle of approach/attack indicator 

AAIB Air Accidents Investigation Branch (of UK DfT) 

AAIM aircraft autonomous integrity monitoring 

aal above aerodrome level 

AALA Adventure Activities Licensing Authority (UK) 

AAPS Automated Aid Positioning System (US) 

AATCU ATCOs’ union in Serbia & Montenegro 

AB Able Seaman 

ab initio ‘from the beginning’ (elementary training) 

ABAS aircraft-based augmentation system 

ABIP Advisory Board of Interested Parties (EASA) 

ABLOS Advisory Board on the Law of the Sea (IHO, IAG & IOC) 

abm abeam (at 90º to track) 

ABn aerodrome beacon 

ABOI Association of British Offshore Industries 

ABP active bus priority (traffic lights) 

ABP Association of British Ports 

London based private company owning several UK ports. 

ABS Acoustic Backscatter System 

ABS American Bureau of Shipping (classification society) 

HQ Houston, TX, USA. European HQ London. 

ABS Automatic Blink System (LORAN-C integrity channel) 

2 

March 2012

absolute accuracy (geodetic or geographic accuracy) 

The accuracy of a position with respect to the geographic or geodetic 

coordinates of the earth (IMO). 

AC Admiralty Chart 

AC Advisory Circular (FAA) 

ac aircraft 

AC altocumulus cloud 

AC Analysis Centre (IGS) 

AC(YPS) Act Activity Centres (Young Persons’ Safety) Act 1995 (UK) 

Acacia Project to develop a definitive, consistent and joined-up national 

infrastructure of property addresses and related data with the 

related mapping. OS, HMLR, RoS, Valuation Office Agency 

(VOA), Improvement and Development Agency (IDeA) and Royal 

Mail. 

ACARE Advisory Council for Aeronautics Research in Europe 

ACARS Aircraft Communications Addressing and Reporting System (ARINC) 

Civil air data link for air-to-ground business and ATS messages. 

ACAS Airborne Collision Avoidance System (=TCAS in USA) 

ACAS-II current from 2000. Mandatory in Europe for ac >5,700 kg 

MTOW or >19 pax seats from 1 Jan 05. 

Acc altocumulus castellanus cloud 

ACCa adaptive cruise control 

ACCa Antarctic Circumpolar Current 

ACCb area control centre (ATC - international; ARTCC in US) 

ACCC Aviation Crisis Coordination Cell 

ACCLAIM Antarctic Circumpolar Current Levels by Altimetry and Island 

Contributes to the World Ocean Circulation Experiment (WOCE) 

of the World Climate Research Programme. 

accuracy The degree of conformance between the estimated or measured 

parameter of a craft at a given time and its true parameter at that 

time (IMO). 

ACDS Aeronautical Charts and Data Section (CAA - moved to NATS 2009) 

ACE Advanced Composition Explorer (NASA 1997 solar wind monitor sat) 

ACE Advanced Configurable EGI 

ACE ATM Cost-Effectiveness (EUROCONTROL Benchmarking Report) 

ACEA Association des Constructeurs Européens d'Automobiles 

Represents the interests of 13 European car, truck and bus 

manufacturers. 

ACEM Agence de Coopération pour l’Europe de la Mer (= ECMA) 

ACF autocorrelation function 

ACFD advanced civil flight deck 

ACG ATM/CNS Consultancy Group (EATCHIP - EUROCONTROL) 

3 

March 2012

ACI Airports Council International 

573 members with 1,640 airports in 178 countries (2008). 

ACID Aircraft Identification (EUROCONTROL) 

ACK acknowledge(ment) 

ACM autocorrelation-matrix 

ACN Active Control Network (UK OS) 

ACN Airspace Co-ordination Notice 

ACO Aircraft Certification Office 

ACP Airspace Change Proposal (UK CAA) 

ACR aerodrome control radar 

ACRUDA Assessment and Certification RUles for Digital Architectures (EU) 

ACTD advanced concept technology demo 

ActMAP EC project to bring real-time info to in-vehicle digital maps 

ACZ aerodrome control zone 

AD air data 

AD Airworthiness Directive 

Issued by airworthiness authority to correct a defect found after 

certification. Mandatory. 

ADA advisory area (ATC) 

ADACU advanced digital antenna control unit (eg for GPS steerable array) 

ADAM Airport Datum Management Program (US) 

ADAS Advanced Driver Assistance System 

ADC aerodrome control(ler) 

ADC air data computer 

ADC analogue-to-digital converter 

ADCC Air Defence Control Centre 

ADCP Acoustic Doppler Current Profiler 

ADD aircraft-derived data 

ADD airstream direction detector 

ADD average delay per delayed flight (air traffic flow management) 

Address Point Dataset to uniquely defines & locate residential, business and 

public postal addresses in GB. Matches info fm OS digital map 

databases with >26 million addresses in the Royal Mail PAF. 

ADEOS ADvanced Earth Observation Satellite (Japan) 

ADEXP ATS Data Exchange Protocol (EATMP) 

ADF automatic direction find(er)(ing) 

ADI attitude director indicator 

ADIRS air data inertial reference system 

ADIRU air data inertial reference unit 

ADM average delay per movement (air traffic flow management) 

ADMAP Antarctic Digital Magnetic Anomaly Project 

ADN Euro Ag’ment on int carriage of dangerous goods by inland waterways 

4 

March 2012

ADNM Admiralty Digital Notice to Mariners 

ADONIS EU project to make cycling and walking safer 

ADP Admiralty Digital Products (UKHO) 

ADPCM adaptive differential pulse code modulation 

ADQIR Aeronautical Data Quality Implementing Rule (EU) 

ADR accident data recorder 

ADR advisory route (ATC) 

ADR air data reference 

ADR architectural design review 

ADR automotive dead reckoning (typically aiding vehicle GPS) 

ADR European Agreement on intnat’l carriage of dangerous goods by road 

ADRIS automatic DR indicating system 

ADRU Air Defence Radar Unit 

ADS Automatic Dependent Surveillance 

ADS-B Automatic Dependent Surveillance - Broadcast 

Aircraft broadcast their identity, position (GNSS-based) 

and velocity. This can be captured by receivers on the ground 

(ADS-B out) or in aircraft (ADS-B in). 

ADS-C Automatic Dependent Surveillance - Contract 

Based on contract between a ground system and aircraft: demand 

contract, periodic contract, event contract and emergency contract. 

ADSL Asymmetric Digital Subscriber Line 

For access to the Web using normal phone lines at speeds between 512 

and 2,000 kbps. 

ADSP Automatic Dependent Surveillance Panel (of ICAO) 

ADVANCE Advanced Driver & Vehicle Advisory Navigation Concept (US) 

ADVANTIS Project looking at integrity for liability-critical applications (GJU) 

AE antenna electronics 

a e 

Earth’s equatorial radius (typically 6.378 x 10 6 m) 

AEA Association of European Airlines 

AEEC Airlines Electronic Engineering Committee (US) 

AEI air experience instructor 

AENA Aeropuertos Españoles y Navegación Aérea (Spanish ATSP) 

AEP Architecture Evolution Plan 

GPS ground control Unix-based system from Apr 07. 

AEROSAT Aeronautical Satellite (Programme) 

AESA active electronically scanned array (radar) 

AESIG Asociacion Espanola de Sistems de Informacion Geografica y Territo 

AEW airborne early warning 

AF adaptive filtering 

AFB Air Force Base (US) 

AFC automatic frequency control (eg in radar) 

5 

March 2012

AFCI arc fault circuit interruption (to detect aircraft wiring problems) 

AFCS automatic flight control system 

AFDC autopilot flight director computer 

aFDPS Advanced Flight Data Processing System (precursor to SESAR) 

AFDS autopilot flight director system 

AFDX E/S aircraft full-duplex end system 

AFG Advisory Financial Group (EUROCONTROL) 

AFI assistant flying instructor 

AFI automatic fault indication 

AFIGEO Association français pour l’Information Géographique 

AFIS airfield flight information service (info but not control) 

AFLT Advanced Forward Look Trilateration 

To calculate position of a mobile handset on CDMA network. 

AfOL Association for Outdoor Learning (UK) 

AFRAA African Airlines Association 

AFRIN Associate Fellow of the Royal Institute of Navigation 

AFS Aeronautical Fixed Service (comms) 

AFS Air Force Station (US) 

AFS atomic frequency standard 

AFSPC Air Force Space Command (USAF) 

AFSS automated flight service station 

AFTN Aeronautical Fixed Telecommunication Network 

AGAS Action Group for ATM Safety (EUROCONTROL) 

Set up as high-level group as result of 1 Jul 02 mid-air collision. 

AGC Air/Ground Cooperative (Air Traffic Services Programme) 

AGC automatic gain control 

AGER Annual GPS Enterprise Review (US Defense Acquisition Board) 

AGI air ground incident 

AGI Association for Geographic Information (UK) 

AGILE Application of Galileo in the LBS environment (EC FP6 2005-07) 

agl above ground level 

AGNA Advisory Group of National Authorities (EASA) 

AGNIS Azimuth Guidance for Nose-in Stand (aircraft parking system) 

AGNSS (A-GNSS) Assisted GNSS 

AGO automatic geophysical observatory 

AGORA Implementation of Global Location Referencing Approach 

EC telematics project Oct 2000 - Apr 2002. 

AGPS (A-GPS) Assisted GPS 

AGS Association of Geotechnical and Geo-environmental Specialists 

AGU American Geophysical Union 

AHARS attitude and heading reference system 

6 

March 2012

AHEAD EUROCONTROL programme to develop web-based AIS 

AHMS Aeronautical Mesage Handling System (replaced AFTN) 

AHRS attitude and heading reference system 

AHS Advanced Cruise-Assist Highway Systems (Japanese concept) 

AHS automated highway system 

AHWG ad-hoc working group 

AI Accuracy and Integrity (Galileo Service) 

AI attitude indicator 

AIAA American Institute of Aeronautics and Astronautics 

AIAA area of intense aerial activity 

AIB Accident Investigation Board 

AIC Aeronautical Information Circular 

AIC Automotive Information Centre (MIRA) 

AIDU Aeronauical Information Documents Unit (RAF Northolt) 

AIG Association international de géodésie (IAG) 

AIM Aeronautical Information Management 

AIM autonomous integrity monitoring (eg CAIM, RAIM) 

AIMR Aeronautical Information Management Regulation 

AIN Arab Institute of Navigation 

AION Australian Institute of Navigation 

AIP Administrative Incentive Pricing 

Spectrum pricing to reflect its value to the user. 

AIP Aeronautical Information Publication 

AIPA Australian & International Pilots Association 

AIPCN Association Internationale de Navigation (also PIANC) 

Brussels based - www.pianc-aipcn.org. 

AIRPROX UK term for ‘airmiss’ 

AIRS Automatic Ship Identification and Reporting System (UK) 

AIRWAVES Project to use GNSS in aircraft to monitor WV (EUROCONTROL) 

AIS Aeronautical Information Services 

AIS Automatic Identification System (for shipping - IMO) 

For ship-to-ship and ship-to-shore exchange of dynamic (inc pos, SOG, 

COG, hdg, ROT), static (inc MMSI, callsign, name, size, type) and 

voyage (inc draft, cargo, dest, ETA, route plan) data. Uses 2 VHF 

freqs - 161.97 and 162.025 MHz in SOTDMA channels; 1-sec frame 

comprises 2,250 slots each of 256 bits. Capacity ~ 4,000 reports/min. 

AISM Association Internationale de Signalisation Maritime (IALA) 

AISSat-1 Demonstrator satellite to receive and relay AIS 

Norwegian satellite launched by India in May 2010. 

AIST National Inst of Advanced Industrial Science & Technology (Japan) 

AIV all in view (receiver) 

AIV assembly, integration and verification (eg EGNOS) 

7 

March 2012

AIVP assembly, integration and verification plan (eg EGNOS) 

AIWG Airspace Infringements Working Group (CAA) 

AIXM Aeronautical Information Exchange Model (EUROCONTROL) 

AIZ aerodrome information zone 

AL alert limit/level 

Max allowable error (in a measured position for example) found during 

integrity monitoring before an alarm is triggered. 

ALA approach and landing accident 

ALAR Approach and Landing Accident Reduction (FSF initiative) 

ALARP as low as reasonably practicable (of risk in using a system) 

ALC Automatic Level Control 

Alert The International Maritime Human Element Bulletin (NI & Lloyd’s R) 

ALFENS Automated Low Flying Enquiry & Notification System 

ALI automatic location identification 

aliasing Visibly jagged steps along angled lines/edges (displays & maps) 

ALIVE ALert Interface Via EGNOS 

System to broadcast warning messages (e.g. of natural disasters) in 

addition to the EGNOS correction signals. 

ALL Admiralty List of Lights 

ALNOT Alert Notice (of aircraft overdue) 

along-track error A position error in the direction of the intended track (IMO). 

ALPA Air Line Pilots Association (US) 

ALPR automatic licence-plate recognition 

ALRS Admiralty List of Radio Signals 

ALS aerodrome lighting system 

AltBOC Alternate Binary-Offset-Carrier 

Constant envelop modulation scheme for combining 2 sidebands each 

consisting itself of 2 binary signals (in I- and Q-channel). 

AltBOC(n,m) AltBOC with chipping rate of m x 1.023 Mcps and sub-carrier 

frequency of n x 1.023 MHz. 

AM amplitude modulation 

AM ante meridian (before noon) 

AM/FM Europe Automated Mapping/Facilities Management - European Division 

AM/FM It Automated Mapping/Facilities Management - Italy 

AMASS Airport Movement Area Safety System (FAA) (software package) 

ambiguity The condition obtained when one set of measurements derived from a 

navigation system defines more than one point, direction, LOP or 

surface of position (IMO). 

AMCP Aeronautical Mobile Communication Panel (of ICAO) 

AMCS Alternate Master Control Station (GPS) - Vandenberg AFB 

AMDR Aircraft Meteorological Data Relay 

AME authorised medical examiner (for aviation licences) 

AMI-C Automotive Multimedia Interface Collaboration (telematics standard) 

8 

March 2012

AMLCD active matrix liquid crystal display 

AMMITEC Assoc of Maritime Managers of Information Technology & Comms 

AMN autonomous marine navigation 

amphidrome A point in the sea where there is zero tidal amplitude due to 

cancelling of tidal waves. Cotidal lines radiate from an 

amphidromic point and corange lines encircle it. 

AMSA Australian Maritime Safety Agency 

AMSD Aircraft Maintenance Standards Department (CAA SRG) 

amsl above mean sea level 

AMSS Aeronautical Mobile Satellite Service 

AMTICS Advanced Mobile Traffic Info & Communication System (Japan) 

AMU air mileage unit 

AMU airborne mapping unit 

AMVER Automated Mutual-Assistance VEssel Rescue System (USCG) 

AN Airworthiness Notice 

ANA area navigation approach 

ANASTASIA Airborne New and Advanced Satellite techniques and 

Technologies in A System Integrated Approach (EC FP6 project) 

ANAVnet On-line application to distribute marine warnings (IHPT) 

ANC Air Navigation Commission (ICAO) 

Android mobile phone operating system for web (Google) 2008 

ANMS Automated Notice to Mariners System 

ANO Air Navigation Order 

Statutory legal instrument defining the laws of air navigation, pilot 

licensing etc in UK. 

ANP actual navigation performance 

ANPA Advanced Notice of Proposed Amendment (JAR-OPS) 

ANPAC Associazione Nazionale Piloti Aviazione Commerciale (It pilots Assoc) 

ANPCAT ATCOs’ union in Italy 

ANPR automatic number plate recognition 

ANR active noise reduction 

ANSEP Air Navigation Services Economics Panel (ICAO) 

ANSI American National Standards Institute 

ANSP air navigation service provider 

ANT Airspace and Navigation Team (EUROCONTROL) 

ANT antenna 

AOA Airport Operators Association 

AOA angle of arrival 

AOB angle of bank 

AOC Advanced Operational Capability 

AOC aerodrome/airport obstruction chart 

AOC aeronautical operational control (US military) 

9 

March 2012

AOC Air Operator’s Certificate 

AOC aircraft operations centre 

AOC airline operational control 

AOC airline operations communications 

AOC auxiliary output chip 

AOM aircraft operating manual 

AOO area of operations 

AOPA Aircraft Owners and Pilots Association 

AOR Atlantic Ocean Region (-E or -W) (of Inmarsat satellites) 

AOR-E at 15.5ºW, AOR-W at 98ºW. 

AP access point 

AP air position 

AP Air Publication (RAF) (AP3456 covers navigation) 

AP assumed position (estimated pos’n for astronomical sight reduction) 

AP autopilot 

APAC Asia and Pacific (ICAO area) 

APAPI abbreviated precision approach path indicator 

APC airline passenger correspondence (eg e-mail, internet, phone) 

APC approach control(ler) (ATC) 

API air position indicator 

API application programming interface 

APL Advanced Positioning Layer (LBS) 

APL airport pseudolite 

APNT alternative positioning, navigation and timing (for when GNSS fails) 

APOLO Advanced POsition LOcator (train location system using GNSS) 

APP approach (control) 

APR approach control radar 

APRS automatic position reporting system 

APTS Advanced Public Transport System 

APU auxiliary power unit 

APV-I Approach with Vertical Guidance - 1 (to runway) 

Requires accuracies (95%) of 220 m H, 20 m V. HAL 556 m, VAL 

50 m. Time to alert 10 s. Definition may be changed by FAA in 2002 

-03. 

APV-II Approach with Vertical Guidance - 2 (to runway) 

Requires accuracies (95%) of 16 m H, 8 m V. HAL 40 m, VAL 20 m. 

Time to alert 6 s. 

AR augmented reality (VR images overlaid on the real world) 

AR autoregressive (form of Kalman filter) 

ARA airspace restricted area 

ARAIM advanced RAIM 

ARB Airworthiness Requirements Board (CAA) 

10 

March 2012

ARC Atlantic Rally for Cruisers 

ARC Aviation Rulemaking Committee (US) 

ARCC Aeronautical Rescue Co-ordination Centre 

ARCC Associated Rescue Co-ordination Centre 

Centre nominated by national SAR agency to which CES normally routes 

distress calls. 

ARCS Admiralty Raster Chart Service 

ARCS automatic route control system 

ARCSSTE-E African Regional Cen for Space Sci and Tech Education in English 

ARINC Aeronautical Radio Inc (now just called ‘ARINC’) 

US avionics standards-setting body whose standards are accepted 

world-wide. 

ARKTRANS Norwegian ITS architecture 

ARM Series of processor cores from ARM Ltd 

ARMAS Active Road Management Assisted by Satellite (ESA project) 

ARN ATS Route Network 

ARNS Aeronautical RadioNavigation Service (of allocated spectrum bands) 

ARP aerodrome reference point 

ARP approximate radial-error protected (algorithm for sat view) 

ARPA automatic radar plotting aid 

ARPU annual/average revenue per user/unit (of eg a telematics service) 

ARSR air route surveillance radar 

ARTCC air route traffic control centre (US; ACC internationally) 

ARTEMIS Advanced Relay and TEchnology MIssion Satellite (ESA) 

Carries EGNOS navigation payload. 21.5ºE. 

ARTES Advanced Research in TElecommunications Systems 

ESA initiatives. Element 9 involves development work for GNSS. 

ARTIST Austrian Radionav Tech & Integrated Sat Nav Servs & Products 

ARTIST Italian ITS architecture 

ARU aircraft retained unit (piece of aircrew equip that stays with the ac) 

ARW angular random walk (of a gyro) 

As altostratus cloud 

AS anti-spoofing 

Method of protecting against hostile imitation of signals - eg GPS PPS 

AS aviation safety 

ASAB Association of Animal Behaviour 

ASAP Automated Solar Activity Prediction system (NASA/ESA) 

Predicts likelihood of solar flares with 6 hrs notice. 

ASAP Aviation Safety Action Programme 

ASAS Airborne Separation Assurance System 

11 

March 2012

ASCII American Standard Code for Information Interchange 

Comprises letters, digits and special characters each represented by 8 

bits or 1 byte. 

ASDE airport surface detection equipment (radar) (can feed AMASS) 

ASDL Aeronautical Satellite Data Link 

ASDO automatic selective door operation (rail) 

ASE altimetry system error 

ASECAP Association Européenne de Concessionnaires d’Autoroutes et 

d’Ouvrages à Péage 

ASF additional secondary factor (cause of Loran sig delay - also PF & SF) 

ASF Air Safety Foundation (of the US AOPA) 

ASHTAM Volcanic Ash NOTAM 

ASI Agenzia Spatziale Italiana (Italian National Space Agency) 

ASI Airspace and Safety Initiative (UK CAA, NATS, AOA, MoD) 

ASI airspeed indicator 

ASIC application-specific integrated circuit 

An IC designed or adapted for a specific application. 

ASK available seat kilometres (a measure of civil available air capacity) 

asl above sea level 

ASL application simulation level 

ASM airspace management 

ASMGCS Advanced Surface Movement Guidance and Control System (airfield) 

ASMI airfield surface movement indicator 

ASMS advanced satellite mobile system (future comms) 

ASOS Automated Surface Observation System (US - air) 

ASP application service provider 

ASP average selling price 

ASQF Application Specific Qualification Facility (EGNOS - Torrejon) 

ASR airport/airfield surveillance radar 

ASR altimeter setting region 

ASR aviation safety report 

ASR-WSP airport surveillance radar - weather systems processor (FAA) 

ASRS Aviation Safety Reporting System (NASA) 

Assignment Authorisation given by a licensing authority for a radio station to use a 

specific radio frequency or channel under specified conditions. 

ASSIST Alpine Safety, Security & Informational Services & Technologies 

ASSP Application Specific Standard Product 

IC dedicated to one specific application (like a custom IC) 

but with several possible customers (unlike a custom IC). 

ASTE Advanced System Telecommunication Equipment programme (ESA) 

12 

March 2012

ASTRA Application of Space Techniques Related to Aviation 

ASTRAEA Autonomous Sys Technology Related Airborne Eval & Assessment 

Project to develop the next-generation of UAVs for civil applications. 

ASTRON Applications on the Synergy of Earth Obs with Sat Telecoms & Nav 

Under EC 5th Framework RTD Programme. 

Astronomical lat Angular distance between the plane of the celestial equator and the 

point’s plumb line. 

Astronomical lon Angle between the plane of the prime meridian and the plane of the 

point’s celestial meridian. 

ASV Advanced Safety Vehicle (Japanese concept) 

AT atomic time 

AT-VASIS Abbreviated ‘T’ Visual Approach Slope Indicator System 

ATA actual time of arrival 

ATA Air Transport Alliance (EU) 

ATA Air Transport Association (US) 

ATA automatic tracking aid 

ATAG Air Transport Action Group 

Industry lobby gp, 80 members funded by IATA, Boeing and Airbus. 

ATC adaptive tightly-coupled (eg GPS/INS integration) 

ATC air traffic control 

ATC ancillary terrestrial component (broadband fixed transmitters) 

ATC automatic traffic counter (roads) 

ATC automatic train control 

ATC EUC Air Traffic Control European Union Co-ordination (~8,000 ATCOs) 

ATCAA air traffic control assigned airspace 

ATCC air traffic control centre 

ATCO air traffic control officer 

ATCRBS Air Traffic Control and Radar Beacon System 

ATCRU air traffic control radar unit 

ATD actual time of departure 

ATE along track error 

ATE automatic test equipment 

ATF adaptive transversal filter (eg for minimising jamming signals) 

ATFM air traffic flow management 

ATIS advanced traveller information system 

ATIS Alliance for Telecommunications Industry Solutions (US) 

ATIS automatic terminal information station/service 

Continuous broadcast of routine non-control aerodrome information. 

ATK available tonne kilometres 

Measures air available total capacity (combined passenger and cargo). 

ATLAS Airborne Topographic Laser System (QinetiQ) 

ATLB Air Transport Licensing Board 

13 

March 2012

atm atmosphere unit (1 atm = 1.01325 bar = 1013.25 mb or hPa) 

ATM aerodrome traffic monitor 

ATM air traffic management 

ATM2000 is EUROCONTROL’s ‘gate-to-gate’ strategy initiative to 

2015. 

ATM asynchronous transfer mode (eg EGNOS) 

Atmosphere Shell round earth extending to height of 350 km 

Comprises troposphere, stratosphere, mesosphere, thermosphere and 

ionosphere. 

ATMS advanced traffic management system 

ATMSP Air Traffic Management Service Provider 

eg: AENA - Spain, ANA - Portugal, DFS - Germany, DGAC - France, 

ENAV - Italy, NATS - UK. 

ATMWG Air Traffic Management Working Group (IATA) 

ATN Aeronautical Telecommunications Network 

ATOL Association of Tour Operators and Leaders 

AtoN (ATON) aid(s) to navigation 

ATOP Advanced Technologies and Oceanic Procedures (FAA) 

ATP Allied Tactical Publication (NATO) 

ATP Automatic Train Protection (UK signalling safeguard) 

ATPI Along the Track Protection Interval (trains) 

ATPL Air Transport Pilot’s Licence 

ATR Air Transport Racking (ARINC) 

A standard size for avionics boxes. All 10 ins high, full ATR 10 ins 

wide, half ATR 5 ins wide etc. 

ATS air traffic service 

ATS Aircrew Training System (USAF) 

ATSA air traffic service assistant 

ATSB Australian Transport Safety Board 

ATSI air traffic services investigations 

ATSIN Air Traffic Services Information Notice (CAA) 

ATSOCAS air traffic services outside controlled airspace 

ATSP Air Traffic Service Provider 

ATSU air traffic service unit 

ATT Admiralty Tide Tables 

ATT advanced transport telematics 

ATTS advanced transport telematics system 

ATZ aerodrome traffic zone 

Usually 2 or 2.5 n miles radius up to 2,000ft aal. 

AU astronomical unit 

AUC Air Transport Users' Council (UK CAA - 12-20 members) 

augmentation Any technique of providing enhancement in order to provide improved 

navigation performance to the user (IMO). 

14 

March 2012

AUGUR A predictive GPS receiver autonomous integrity monitoring system 

EUROCONTROL. 

AUM all-up mass (aircraft) 

AUTM Authorised Unusable Time (NELS Loran-C - see also UTM and EUTM) 

Scheduled and authorised UTM with at least 72 hrs of notice. 

AutoBAHN Pinpoint project towards millimetre accurate real-time positioning 

Newcastle University & LogicaCMG. 

AUTS additional user terminal sensor (GNSS) 

AUV autonomous underwater vehicle 

AUW all-up weight (aircraft) 

availability The percentage of time that an aid, or system of aids, is performing a 

required function under stated conditions (IMO). 

Signal availability - of a radio signal in a specified coverage area. 

System availability - of a system to a user, including signal availability 

and the performance of the receiver. 

AVC automatic vehicle classification 

AVCS Admiralty Vector Chart Service (UKHO) 

AVCS advanced vehicle control system 

AVG automatic vehicle guidance 

avgas aviation gasoline (for piston aircraft) 

AVI automatic vehicle identification 

AVIC audio, video, information and communication (eg for aircraft pax) 

AVID Added Value Information Dissemination (EU project) 

AVL automatic vehicle location 

AVLS automatic vehicle location system 

AVM automatic vehicle monitoring 

AVOID Airborne Volcanic Object Imaging Detector (easyJet + NILU) 

AVOL aerodrome visibility operational level 

AvSALT Aviation Safety Adviser Liaison Team 

AVT Applied Vehicle Technology Panel (NATO RTO) 

avtur aviation turbine fuel (kerosine) (for jets/turboprops) 

AWAC airborne warning & control 

AWARE Advanced Weather and Reporting Enhancements 

Tool being developed by NASA to present better weather info for GA 

pilots. 

AWDS Automated Weather Distribution System 

AWG Airline Working Group (sub-group of NATMAC) 

AWG aural warning generator 

AWGAS Aerial Work & General Aviation Sub-Ctee (JAA) 

AWGN additive white Gaussian noise 

AWN Aviation Weather Network (US) 

AWNIS Allied Worldwide Navigational Information System 

Classified NATO navigational warning system. 

15 

March 2012

AWO all-weather operations 

AWOP All-Weather Operations Panel (ICAO) 

AWOS Automated Weather Observing System 

AWP automated weather processor 

AWPR automatic waypoint reporting 

AWR airborne weather radar 

AWS Automatic Warning System (UK railways) 

AWU annual work unit 

Awy airway 

az azimuth 

B-band NATO radar band 250-500 MHz = 1.2-0.6 m 

B-Call breakdown call (GPT) 

B-GAN Broadband Global Area Network (432 kbps on Inmarsat I-4 

B-RNAV basic area navigation 

ICAO definition - having a nav performance equal to or better than a 

track-keeping accuracy of ±5 NM 95% of time. 

B2B business-to-business (electronic commerce) 

BA British Admiralty 

BA British Airways 

BAA British Airports Authority 

BAA Broad Agency Announcement (US) 

BABS Blind Approach Beacon System (1941) 

BAFEGIS Baltic Ferry Guidance and Information System 

BALPA British Air Line Pilots Association 

BANET Baltic & N Sea ECDIS Test-Bed 

BAPE best available position estimate 

bar Pressure of 1,000,000 dynes per square cm 

1 bar = 0.987 atm = 14.5038 psi = 29.53 inHg 

baroclinic Atmospheric condition in which isobaric and constant-density 

surfaces are not parallel. In the ocean when surfaces of 

constant pressure intersect surfaces of constant density. 

barotropic A state in a water mass in which the surfaces of constant 

pressure are parallel to the surfaces of constant density. 

BATA British Air Transport Association 

BATCU ATCOs’ union in Bulgaria 

bathymetry The charting of the ocean floor by taking soundings 

BAUA Business Aircraft Users Association (UK) 

baud rate of transfer of binary messages 

1 baud = 1 bit per second for most purposes. 

BB baseband 

BB Brown Box (Europort pilot portable radio navigation system) 

BBAC British Balloon and Airship Club 

16 

March 2012

BBGA British Business and General Aviation Association 

BBKMF Black Box Key Management Facility (Galileo) 

BBP beam bend potential (ILS) 

BBR battery backup RAM 

BC patches (met) 

BC Code Code of Safe Practice for Solid Bulk Cargoes (IMO) 

BCAR British Civil Air Requirements 

BCAS beacon-based collision avoidance system 

BCBP bar coded boarding pass (IATA - full implementation by 2010) 

BCCH broadcast control channel (GSM phones) 

BCD binary code decimal 

BCH broadcast channel (phone network) 

bcn (BCN) BeaCoN 

BCR bow crossing range 

BCS beacon control system (marine) 

BCS British Cartographic Society 

BCT bow crossing time 

BCU British Canoe Union 

BDIS Bus Departure Infomation System 

BEA Bureau Enquêtes-Accidents (French AAIB) 

BECMG becoming (met) 

BEDMAP Antarctic Bedrock Mapping Project 

Beidou Chinese GNSS (means ‘Big Dipper') 

BER bit error rate 

Also known as Twinstar Rapid Positioning System. 2 sats in 

geosynchronous orbits, may be joined by 2 more or may become a 

full constellation (also known as ‘Compass’). 

BERR Dept for Business, Enterprise and Regulatory Reform (UK fm Jun 07) 

BEST Beginning-to-End for Simulation and Training 

NATS ATC simulation system for NERC. 

BFO beat frequency oscillator 

BFU Bundesstelle für Flugunfalluntersuchung (German AAIB) 

BGA ball grid array (type of surface-mount packaging used for ICs) 

BGA British Gliding Association 

BGD broadcast group delay 

BHAB British Helicopter Advisory Board 

BHPA British Hang Gliding and Paragliding Association 

BIAS Bus Information and Signalling System 

BiCMOS Combined CMOS & bipolar trans for logic & memory on the same chip 

BIGF British Isles GPS (archive) Facility (NERC) 

BIH Bureau International de L’Heure 

BIIT built-in integrity test 

17 

March 2012

Bimco Baltic and International Maritime Council 

BINA British Isles/North America (eg ERS) 

BIPM Bureau International des Poids et Mesures (under CGPM) 

BIS Department for Business Innovation & Skills (UK) 

bit binary digit 

A single unit of binary data. 

BIT built-in test 

BKN broken cloud (5 to 7 oktas) 

BL blowing (met) 

BLA bi-lateral agreement 

black-box testing Testing that ignores internal workings and structure of a component 

See white-box testing. 

BLE Bluetooth Low Energy (protocol V4.0) 

Block Batch of GPS satellites made to a common standard 

BlockII/IIA from Feb 89; 28 launched. Block IIR from Jul 97. Block 

IIF from 2006 with L5. Block III from ~2013. 

BLUE best linear unbiassed estimate 

Blue Belt EASA system to allow ships not leaving the EU to get quick customs 

clearance and reduce need for extensive comms with authorities. 

Bluetooth Specification for wireless comms between terminals & peripherals 

Up to 10 metres using 2.4 GHz at 720 kbps. Promoted by Ericsson, 

IBM, Intel, Nokia & Toshiba. Named after 10th century Viking king. 

BM base model 

BMAA British Microlight Aircraft Association 

BMC British Moutaineering Council 

BMEA British Marine Equipment Association 

BMIF British Marine Industries Federation Ltd 

Bn beacon 

BNEA British Naval Equipment Association 

BNS Brunel Navigation System (for visually impaired pedestrians) 

BNSC British National Space Centre 

BNTS Beidou Navigation Test Satellite (China)(first 2 launched Oct 00) 

BNWAS Bridge Navigational Watch Alarm System 

BOC binary offset carrier 

A form of modulation using a sine-shaped sub-carrier modulated at the 

required data rate. Referred to as BOC (n,m) where n = subcarrier 

freq and m = code chipping rate. Used in GPS M-code and Galileo. 

BOCc binary offset carrier using cosine-shaped sub-carrier 

BOD bearing origin to destination 

BOM bill of material 

BOSCA British Oil Spill Control Association 

BOSS Broad Ocean Surveillance System (US - out to 2,000 NM) 

18 

March 2012

BOSVA British Offshore Support Vessel Owners Association 

BOW basic operating weight (everything except payload) 

BPA British Parachute Association 

BPA British Ports Association (Trade association reoresenting ~ 87 ports) 

BPEO Best Practicable Environmental Option 

BPL Basic Positioning Layer (LBS) 

BPR bottom pressure recorder 

BPR Brinnenvaart Politie Reglement (Dutch derivative of CEVNI) 

BPRZ bi-polar return-to-zero (digital channel) 

bps bits per second 

BPSK bipolar (or binary) phase shift keying 

BPSK(m) BPSK using a chipping rate of m x 1.023 Mcps 

BR mist (met) 

brg bearing 

BRNAV basic area navigation (en route) 

BROA British Rig Owners Association 

BS British Standard 

BS broadband services 

BS EN British Standards European Norm 

BSH Bundesamt für Seeschiffahrt und Hydrographie (German HO) 

BSI British Standards Institution 

BSI/EN/ISO tri-numbered standard (British/European/International) 

BST British Summer Time 

BT British Telecom 

BTS base transceiver station (phone network) 

BTS Bureau of Transportation Statistics (US) 

BV Bureau Veritas (classification society) 

BWB British Waterways Board 

BWC bearing and distance to waypoint (great circle) 

BWEA British Wind Energy Association 

BWPA British Women Pilots’ Association 

BWR bearing and distance to waypoint (rhum line) 

BWW bearing waypoint to waypoint 

By buoy 

byte binary word (often of 8 bits) 

c centi (SI unit multiplier of 10 -2 ) 

c speed of light in vacuo (2.997 924 590 x 10 8 m s -1 ) 

C a ºCelsius 

C GNSS GNSS radio signals in C-band 

C of A Certificate of Airworthiness (issued by CAA in UK) 

C of C Certificate of Conformity (usually of equipment) 

19 

March 2012

C-band NATO radar band 0.5-1 GHz = 60-30 cm 

C-band Old radar band 4-8 GHz = 7.5-3.75 cm 

(ITU assigned 5,250-5,925 MHz). 

C-TPAT Trade Partnership Against Terrorism (US) 

C/A Coarse Acquisition code (of GPS) 

Family of PRN codes, one of 32 allocated to each satellite. Each code 

has 1,023 chips sent at 1.023 Mbps, repeating every ms. 

C/No (C/N) carrier-to-noise power density 

Ratio of power level of a signal carrier to the noise power in a 1 Hz 

bandwidth. 

C/NOFS Communications/Navigation Outage Forecasting System (US sat) 

c/s callsign 

C&SMWG Colours & Symbols Maintenance Working Group (of IHO CHRIS) 

C&V corrections and verification (WAAS software) 

C2C car-to-car (eg comms) 

C4ISR Command, Control, Communications, Computers, Intelligence, 

Surveillance & Reconnaisance. 

CA civil aviation 

CA Coordination Action (EU FP6) 

CAA Cargo Airlines Association (US) 

CAA Civil Aviation Authority (UK) 

CAAC Civil Aviation Administration of China 

CAASD Center for Advanced Aviation System Development (MITRE US) 

CAATS Canadian Automated Air Traffic System 

cable 1/10th nautical mile ~ 185.2 m 

CABSINET Cellular Access to Broadband Services and Interactive Television 

CACS comprehensive automobile traffic control system 

CAD computer-aided design 

CAD computer-aided dispatch (system) 

CADC central air data computer 

CADRT computer-aided dead reckoning tracer (part of SCDS - USN) 

CAE computer-aided engineering 

CAeM Committee for Aeronautical Meteorology (WMO) 

CAEP Committee on Aviation Environmental Protection (ICAO) 

CAGR compound annual growth rate 

CAIC configurable avionics interface card 

CAIM craft autonomous integrity monitoring 

CAIT Controlled Airspace Infringement Tool (NATS) 

CAIV cost as an independent variable 

CALDOVREP Dover Mandatory Reporting System 

CALF Chart Amendment - Low Flying 

CALM catenary anchor leg mooring 

20 

March 2012

CAM computer-aided manufacture 

CAMELOT Coastal Area Modelling for Engineering in the Long-Term (MAFF) 

CAMO Continued Airworthiness and Maintenance Management 

CAMUS an in-vehicle data bus 

CAN controller area network (in-vehicle data link protocol)(EN 50325-1) 

CANopen Application layer & comms profile for CAN-based networks 

Specified in prEN 50325-4. 

CANP Civil Aviation Notification Procedure (for low-level flying) 

CANPA constant-angle precision approach (air) 

CANSO Civil Air Navigaion Services Organisation 

CAO Coordinating Agency Office (NELS)(Oslo, Norway) 

CAP central alerting post 

CAP Civil Aviation Publication 

CAP Condition Assessment Programme (survey) 

CAP controller access parameter (SSR Mode S) 

CAPA Coalition of Airline Pilots’ Associations (US) 

Capstone FANS ADS-B system implemented in Alaska from early 2001 

CARAD Civil Aerospace Research and Development (Programme) (DTI) 

CARAT CNS Appl’n for Intern’l & Regional Airp’ts App, Lndg & Dep Traffic 

CARDME Concerted Action on Road Demand Management in Europe 

CARIN Car Information and Navigation System 

Autonomous in-car route guidance system from Philips. 

CARPILOT An autonomous in-car navigation system 

Uses DR and map-matching. Netherlands. 

CARS 21 Competitive Automotive Regulatory System for the 21st Century - EC 

CAS calibrated/corrected airspeed 

IAS corrected for air density and compressibility. 

CAS collision avoidance system 

CAS Conditional Assessment Scheme 

An enhanced additional inspection scheme specially developed to 

detect structural weaknesses in single-hull tankers. 

CAS Controlled Access Service (of Galileo - for registered users only) 

CAS 1 has guaranteed performance for commercial applications. 

CAS 2 is certifiable for safety-of-life and security-related 

applications, eg SAS and GAS. 

CAS controlled airspace 

CASA Civil Aviation Safety Authority (Australia) 

CASC China Aerospace Science & Technology Corporation 

CASCADE EUROCONTROL prog to implement initial ADS-B applications 

CASE Collaborative Awards in Science and Engineering (fund PhD students) 

CASIMO European air traffic modernisation prog (>50 projects) 

CASITAF CNS/ATM Systems Implementation Task Force 

21 

March 2012

CASST Commercial Aviation Safety Strategy Team (FAA) 

CAT clear-air turbulence 

CAT commercial air transport 

Sheduled/non-scheduled passenger flights in airliners and helicopters. 

Cargo flights. 

CAT I Category (of ILS service) 

Precision runway approach to height above touchdown of not less than 

200 ft and RVR not less than 2,400 ft (with touchdown & centreline 

lights 1,800 ft (A,B or C) or 2,000 ft (D)). Requires accuracies (95%) 

of 16 m H, 4-6 m V. HAL 40 m, VAL 10-15 m. Time to alert 6 s. 

CAT II Category (of ILS service) 

Precision runway approach to height above touchdown of not less than 

100 ft and RVR lot less than 1,200 ft. Requires accuracies (95%) of 

6 m H, 1 m V. Time to alert 1 s. 

CAT III Category (of ILS service) 

Precision runway approach - no decision height minimum and RVR not 

less than: A 700 ft, B 150 ft, C no minimum. Requires accuracies (95%) 

of6 m H, 1 m V. Time to alert 1 s. 

CATCU ATCOs’ union in Croatia 

CATRIV Conceptual Analysis for Transportation on Rivers (EU) 

Cave Review Review of UK radio spectrum management by Prof Cave (March 2002) 

CAVOK ‘cav-okay’ - ceiling and visibility OK 

Basically visibility at least 10km and no cloud below 5,000ft. 

CAVU ceiling and visibility unlimited 

Cloudless or scattered cloud and visibility over 10km. 

CB compass bearing (angular distance from CN to the object) 

Cb cumulonimbus cloud 

CBA cost benefit analysis (B) = business, (S) = society 

CBI computer-based information 

CBM conventional buoy marking 

CBOC composite binary offset carrier (modulation) 

CBT computer-based training 

CbyC Correctness by Construction 

Ultra low defect software approach for critical applications. 

CC chronometer correction 

The amount that must be added algebraically to the chronometer time 

to obtain UT. 

CC compass course 

Intended direction of movement (of the ship), defined by the angle 

between compass north and the fore-and-aft line (of the ship), 

expressed in angular units from compass north (000º). 

CC Competition Commission (UK) 

CCAMS Code Assignment and Management System 

EUROCONTROL solution to SSR code shortage. Jan 07. 

22 

March 2012

CCB Change Configuration Board (EGNOS) 

CCB Configuration Control Board (EGNOS) 

CCB Control Centre Brest (NELS) 

CCC Carrier Container Council 

CCC central control system 

CCD charge coupled device 

CCD Crosscutting Capability Demonstrations (NASA) 

CCD cursor control device 

CCF Central Control Facility (EGNOS) 

CCF common cause failure 

CCF Constellation Control Facility (Galileo) 

CCF cross-correlation function 

CCG Canadian Coast Guard 

CCIR International Radio Consultative Committee (of ITU) 

Now called ITU-R. 

CCITT International Consultative Ctee on Telephony and Telegraphy (of 

Now called ITU-T. 

CCN Contract Change Notice (EGNOS) 

CCO Certificate in Coaching Orienteering (L2CCO is Level 2) 

CCRI capacitively coupled resistivity imaging 

CCS China Classification Societies 

CCS complex conjugate symmetric (often refers to signal filters) 

CCSDS Consultative Committee on Space Data Standards 

CCW coded continuous-wave 

CCW coherent continuous-wave 

CCW counter-clockwise 

CCZ coastal confluence zone 

CCZ congestion charging zone 

CD chart datum 

CD compact disk 

cd SI unit of intensity of light 

CD-R compact disk - recordable 

CD-ROM compact disk - read-only memory 

CD-RW compact disk - re-writable 

CDA continuous descent approach (air) 

CDED Canadian Digital Elevation Data 

CDGPS Canada-wide Differential GPS 

CDI course deviation indicator 

CDL code delay line (GNSS rx) 

CDL collision danger line (VCASS) 

CDL configuration deviation list (associated with MEL) 

23 

March 2012

CDLC cellular data link control 

CDM collective decision making (ATC) 

CDMA code division multiple access 

CDR conflict detection and resolution (ATC) 

CDR critical design review 

CDS collision danger sector (VCASS) 

CDTI cockpit display of traffic information (in ADS-B) 

CDU control and display unit 

CE total compass error correction 

Sum of Var and Dev. Angle between TN and CN, from TN eastwards 

named E (+), westwards named W (-). 

CEATS Central European Air Traffic Services (based in Vienna from 2006) 

cec centicycle (1/100th of a cycle) 

CEC Certificate of Equivalent Competency (maritime - IMO) 

CEDEX Centro de Estudios y Experimentación de Obras Públicas (Spain) 

CEECs Central and Eastern European countries 

CEGRN Central European GPS Reference Network 

Over 90 sites in 14 countries 2007. Gives accuracy of 2-4 mm 

horizontal and 4-8 mm vertical. 

CEI Central European Initiative (Scientific programme with 17 nations) 

cel centilane (1/100th of a lane) 

celestial horizon Circle of the celestial sphere formed by the intersection of the 

celestial sphere and a plane through the centre of the earth and 

perpendicular to the zenith-nadis line. 

Cell-ID network cell identification (cellphone positioning) 

Accuracy of 250 m - 10 km. 

CEMT Confederation of European Maritime Technology Societies 

Independent confederation of professional societies from 

France, Greece, Italy, Netherlands, Portugal, Poland, Spain & UK. 

CEN Comité Européen de Normalisation 

European standards body for IT. 

CENC China-Europe GNSS Technical Training and Cooperation Centre 

CENELEC Comité Européen de Normalisation Electrotechnique 

European Committee for Electrotechnical Standardisation. Central 

Secretariat based in Brussels. 

CEO/JRC Centre for Earth Observations/Joint Research Centre 

CEP circular error probable 

The radius of a circle, centred at the measured position, inside which 

the true position lies with 50% probability. For GPS, CEP = 0.83 x 

UERE x HDOP. 

CEP Committee for Environmental Protection 

CEPT Conference of European Postal Telecommunications Administrations 

CER Community of European Railways 

24 

March 2012

CERCO Comité Européen des responsables de la cartographie officielle 

CERGOP Central European Region Geodynamics Project (CEI) 

Phase 1 concluded 1998 led to CEGRN. CERGOP-2 from 2000. 

CERT Computer Emergency Response Team (EU, vs cyber attacks) 

CES coast earth station (same as LES operationally) 

CES Consumer Electronics Show (US) 

CESA Committee of EU Shipbuilders’ Associations 

CESAR Certification Policies, Procedures & Requirements 

For satellite-based navigation and landing systems and corresponding 

research activities. 

CEST Centre for Exploitation of Science and Technology 

CETRF Central European Terrestial Reference Frame 

CEV Centre d’Essais en Vol (French national flight test centre) 

CEVNI Code Européen de Voie de la Navigation Intérieur 

The rules for inland waters of mainland Europe. 

CF compact flash (memory card - typically up to 640 Mb) 

CF course to a fix 

CFAR constant false alarm rate (eg radar) 

CFCA Community Fisheries Control Agency (EU) 

CFI certified flight instructor (US) 

CFI chief flying instructor (UK) 

CFI customer furnished item 

CFIT controlled flight into terrain 

When an airworthy aircraft under the control of the flight crew is 

flown unintentionally into terrain, obstacles or water, usually with no 

prior awareness by the crew. 

CFMU Central Flow Management Unit 

CFR Code of Federal Regulations (US) 

CG Coastguard 

CGAS Coast Guard Air Station (US) 

CGEE self-generated external ephemeris (EE) file 

CGOM Consultative Group on Ocean Mapping (IOC) 

CGPM Conférence Général des Poids et Mesures (Paris) 

Authorised by the Convention of the Metre in Paris in 1875. Now 51 

signatories. 

CGPS continuous GPS (station) 

CGS Centre for Geospacial Science (University of Nottingham) 

CGS Civil GPS Service 

CGSIC Civil GPS Service Interface Committee 

CGU code generation unit (GNSS rx) 

Ch Channel 

25 

March 2012

CH compass heading 

Actual direction in which the longitudinal axis (of the ship) is pointed, 

defined by the angle between compass north and the fore-and-aft line 

(of the ship), expressed in angular units from compass north (000º). 

CH HSS coronal hole high speed stream (of Sun) 

CHA Competent Harbour Authority (UK under the Pilotage Act 1987) 

CHAIN Controlled and Harmonised Aeronautical Information Network 

For improving quality of aeronautical data (EUROCONTROL). 

CHAPI carrier helicopter approach path indicator 

Chayka Russian LORAN-C system 

chip binary element or digit that conveys no information 

CHIRP Confidential Human Factors Incident Reporting Procedure (UK CAA) 

CHO Cooperating Hydrographic Office (of RENC) 

CHP Civil Hydrography Programme 

CHRIS Ctee on Hydrographuc Requirements for Information Systems (IHO) 

CHS Canadian Hydrographic Service 

Ci cirrus cloud 

CI cell identity number (phone network) 

CI confidence interval (statistics) 

CIAIAC Comision de Investigacion de Accidentes e Incidentes de Aviacion Civil 

of Spain. 

CIC cave instructor certificate 

CID Cell ID (mobile phones) 

CIDIN Common ICAO Data Interchange Network 

CIIP critical information infrastructure protection 

CIKR Critical Infrastructure Key Resources (US study) 

CIL Commissioners of Irish Lights (known as Irish Lights) 

Covers all of Ireland. 

CILT(UK) The Chartered Institute of Logistics and Transport in the UK 

Was ILT until May 2004. 

CIN China Institute of Navigation 

CIPM Comité International des Poids et Mesures (under CGPM) 

CIR channel impulse response 

CIR cockpit image recorder 

CIRM Comité International Radio-Maritime 

CIS Commonwealth of Independent States 

CISC complex instruction set computer 

CISPR International Special Committee on Radio Interference 

CIT Chartered Institute of Transport 

CITE conformity & interoperability test & evaluation 

CIWG Communication Infrastructure Working Group (IATA) 

CL Civil-Long (proposed GPS L2 code carrying no data - alongside CM) 

26 

March 2012

CL correlation loss 

Class Category in classification register 

Class A or B Class of AIS installation (A for large ships, B for leisure craft) 

CLCS Commission on the Outer Limits of the Continental Shelf (UN) 

cld cloud 

CLGE Comité de liaison des géomètres Européens 

CLI caller line identification 

CM Civil-Moderate (proposed GPS L2 code carrying data - alongside CL) 

CMA Central Monitoring Agency (NATS) 

CMAG Civil and Military Air Group (RIN SIG) 

CMATZ combined military air traffic zone 

CMCU Clock Monitoring and Control Unit (Galileo) 

CME coronal mass ejection (from Sun) 

CMG course made good (rhumb line direction between 2 fixes) 

CMIC Civil Military Interface Committeei (EUROCONTROL) 

CMID Common Marine Inspection Document (IMCA) 

CMOS complementary metal oxide semiconductor 

CMR civil marine radar 

CMU communications management unit 

CMYK Cyan, Magenta, Yellow and blacK (colour system for printing) 

CN change notice (eg EGNOS) 

CN compass north 

Northerly direction of the needle or zero-index of a magnetic compass. 

CNAV Civil Navigation Message (on GPS second civil signal (L2C)) 

CNC computer numerically controlled 

CNES Centre Nationale d’Etudes Spatiales (French National Space Agency) 

CNIG Centro Nacional de Informacao Geografica (Portugal) 

CNIS Channel Navigation Information Service (Dover) 

CNS central nervous system 

CNS communications, navigation and surveillance 

CNSS Compass Navigation Satellite System (China) 

Eventually comprising 27 MEO, 5 GSO) and 3 IGSO satellites. 

COA course of advance (course to make good) 

Direction from the (ship’s) last fix to next estimated position, 

expressed in angular units from true north. 

COBA cost-benefit analysis 

CoC Certificate of Competency 

CODA Central Office for Delay Analysis (EUROCONTROL) 

CODE Center for Orbit Determination in Europe 

CofV Certificate of Validity 

27 

March 2012

COG course over the ground 

Direction of (the ship’s) movement relative to the earth, measured on 

board (the ship). 

COGO coordinate geometry (algorithms for surveying) 

COGR continuously operating GPS receiver 

COLREGs International Regs for Preventing Collisions at Sea (IRPCS) (IMO) 

CoM centre of mass 

Combi-Road Segregated track for automatic transport control and delivery 

of container freight cargoes (Netherlands). 

COMEDS CONUS Meteorological Distribution System 

COMESA Common Market for Eastern and Southern Africa 

21 African states. Initiatives include adoption of an ‘open skies’ policy 

and a joint CNS/ATM system. 

Compass Another name for the ‘Beidou’ Chinese satnav system 

Compatability no significant inter-system interference 

COMSAR Sub-Ctee on Radiocommunications and Search and Rescue (IMO) 

confidence interval The numerical range within which an unknown is estimated to be with a 

given probability. 

confidence level The percentage of confidence that a given statement is correct or 

that a stated interval includes an unknown. 

confidence limits The extremes of confidence interval. 

CONGO COoperative Network for GIOVE Observation 

Global network of GNSS monitoring stations. 

CONOPS Concept of Operations (US) 

continuity The ability of a system to function within specified performance limits 

without interruption during a specified POP. 

CONUS Continental/Contiguous/Conterminous (48) United States 

CONVERGE Completed (2000) EU project on deployment of ITS 

Conversion angle Angular difference between rhumb line and great circle between two 

points. 

COOPATS Cooperative ATS Concept (EUROCONTROL) 

CoP centre of phase 

CoP Conformity of Production (assessment of client under VCA) 

COP common operating picture 

COPUOS Committee on the Peaceful Use of Outer Space (UN) 

correction The best estimate that can be made of the difference between the 

true and the measured value of a parameter. The sign is such that a 

correction is to be added to an observed reading is taken as positive. 

CORS continuously operating reference station (DGPS) 

COS continuity of service 

COSH Committee on Shipping Hydrography 

COSPAR Committee on Space Research (42 states + 12 scientific bodies 02) 

28 

March 2012

COSPAS- 

SARSAT 

Cosmicheskaya Sistyema Poiska Avarynich Sudov - SAR Sat-aid Trkg 

Satellite-aided SAR system based on low altitude near polar orbit 

satellites designed to locate distress beacons on 121.5 and 406 MHz. 

COSS Committee on Safe Seas (EU) 

COST COoperation in the field of Scientific & Technical research 

Cooperation between 17 European countries: Austria, Belgium, Czech 

Rep, Denmark, Finland, France, Germany, Greece, Hungary, Italy, 

Ireland, Netherlands, Slovakia, Spain, Sweden, Switzerland & UK. 

CoSWP Code of Safe Working Practices for Merchant Seamen 

COTS commercial off-the-shelf (equipment) 

COU change-only update (eg of maps) 

coverage The surface area or space volume in which signals are adequate to 

permit the user to determine position to a specified level of 

performance (after IMO). 

COZDIS Coastal and Oceanic Zones Display and Information System 

CP charging point (for road user charging) 

CP cyclic prefix (to mitigate multipath) 

CPA closest point of approach 

CPD carrier phase difference (signal processing) 

CPD collaborative product design 

CPDLC controller-pilot data link communications 

CPDLC Build 1 is based on VDL Mode 2. 

CPE customer premises equipment 

CPF carotenoid-porphyrin-fullerine 

CPF Central Processing Facility (EGNOS, MSAS) 

CPFPS Central Processing Facility Processing Set (EGNOS) 

CPG Consumer Protection Group 

CPGS casette preparation ground station (flight planning) 

CPL commercial pilot’s licence 

CPL current performance level 

CPLD complex programmable logic device 

CPM Conference Preparatory Meeting (ITU) 

CPRNW Commission on the Promulgation of Radio Navigational Warnings (IMO) 

CPRS confidential position reporting system 

CPS central processing station (GNSS) 

cps cycles per second (Hz) 

CPU central processing unit 

CR change request 

CR common requirements 

CRC cyclic redundancy code 

CRC cyclical redundancy check 

CRCO Central Route Charges Office (EUROCONTROL) 

Responsible for the collection of aviation navigation charges. 

29 

March 2012

CRECTEALC Centro Regional de Educação em Ciência e Tecnologias Espaciais para 

America Latina e Caribe 

CRM cockpit (or crew) resource management 

CRM collision risk model 

CRM customer relationship management (comms) 

cross-track error Position error perpendicular to the intended track. 

CRP compulsory reporting point 

CRPA controlled radiation pattern antenna (eg to combat GPS jamming) 

CRS coast radio station 

CRS course (heading) 

Angle measured in horizontal plane from a reference direction, counted 

clockwise from 000º through 360º, written as a 3 digit number. 

CRT cathode ray tube 

CRU carrier removal (signal processing) 

Cs cirrostratus cloud 

CS Commercial Service (Galileo) 

Uses OS plus 2 additional frequencies for higher data rate and 

improved accuracy. Fee-paying with service guarantee. 

CS control segment 

CS-VLA Certification Specification for Very Light Aircraft (EASA) 

CSA Canadian Space Agency 

CSAC chip-scale atomic clock 

CSAR configuration status accounting report (eg EGNOS) 

CSE course 

CSE course selection error 

CSEL Combat Survivor Evader Locator (US) 

CSG Centre Spatial Guyanais (CNES/ESA launch area close to equator) 

In French Guyana; ideal for launching geo & other satellites. 

CSG computer symbol generator 

CSMA carrier sense multiple access 

CSOC Consolidated Space Operations Centre 

CSR Cab Secure Radio (rail at UHF, but band to be shared from 2006) 

CSR Common Structural Rules (for bulk carriers & tankers from Apr 06) 

CSR CSR plc (formerly Cambridge Silicon Radio) 

CSS Code of Shipmanagement Standards 

CSS customer service station (Galileo) 

CSV Comma Separated Values 

Format for digital mapping - eg OS MasterMap Address Layer 2. 

CT computerised tomography (to image ionosphere electron density) 

CTA control area (ATC) 

CTAF Common Traffic Advisory Frequency (used at small airfields in USA) 

30 

March 2012

CTAS Centre-TRACON Automation System (FAA) 

ATC automation tools - TMA, FAST and DA. 

CTIM container tracking interface module (works at 2.4 GHz) 

CTK cargo tonne kilometres (a measure of civil air capacity) 

CTP Common Transport Policy (EU) 

CTR Chain Time Reference (LORAN-C) 

CTR (CTZ) control zone (ATC) 

CTS course to steer (true course) 

The intended direction of movement (of a ship), defined by the angle 

between the meridian through its position and the fore-and-aft line (of 

the ship), expressed in angular units from true north (000º). 

CTSC Converging Technology and Services Committee (FEI) 

CTTL China Telecommunications Technology Labs (Beijing) 

CTU cargo transport unit 

CTU Czech Technical University 

CTW course through water 

Direction of the ship’s movement through the water, defined by the 

angle between the meridian through its position and the direction of 

the ship’s movement through the water, expressed in angular units 

from true north (000º). 

CTZ (CTR) control zone (ATC) 

Cu cumulus cloud 

CUAP Chart User’s Advisory Panel (of HO) 

CUG closed user group 

CUPT coordinate update 

CURSOR proprietary positioning system using GSM phones 

CV common view (mode of operating GPS or LORAN for time transfer) 

CVHS Co-operative Vehicle Highways System (’platooning’ of vehicles) 

CVIS cooperative vehicle-infrastructure systems 

CVN continuous visual navigation 

CVO commercial vehicle operat/or/ion 

CVR cockpit voice recorder 

CVRS computerised vehicle routing and scheduling 

CW clockwise 

CW continuous-wave 

CWAAS Canadian WAAS 

CWI continuous-wave interference 

CWP controller working position (ATC) 

CWS collision warning system 

cyber-car remote controlled or self-driving robot vehicle - a form of PRT 

CYCC Conference of Yacht Cruising Clubs (main UK clubs) 

CZIN Czech Republic Institute of Navigation 

31 

March 2012

d deci (SI unit multiplier of 10 -1 ) 

D Region Lowest part of ionosphere where most HF absorption occurs by day 

D-AMPS A type of DTMA used by some 2G mobile phone systems 

D-ATIS Digital Automatic Terminal Information Service (air) 

D-band NATO radar band 1-2 GHz = 30-15 cm 

D-OTIS (DOTIS) Digital Operational Terminal Information Service (air) 

d.lat difference of latitude 

Shorter arc of any meridian between the parallels of 2 places. 

d.lon difference of longitude 

The shorter arc of a parallel between the meridians of 2 places. 

D&D Distress and Diversion (UK ATC facility) 

D2B International multimedia networking protocol for use within vehicles 

da deca (SI unit multiplier of 10 1 ) 

DA decision altitude (referenced to sea level) 

DA Descent Advisor (ATC management tool)(US) 

DAAS data as a service 

DAB Defense Acquisition Board (US) 

DAB digital audio broadcast(ing) 

DAC digital-to-analogue converter 

DACS Danger Area Crossing Service (UK CAA/NATS) 

DADI datalinking of aircraft-derived information 

DAGR Defense Advanced GPS Receiver (US) 

DAISY Digital Automatic Identification System 

DAP database assisted positioning 

DAP Directorate of Airspace Policy (CAA) 

DAP downlink aircraft parameter (SSR Mode S) 

DAPS data access protocol system (ATC Mode S) 

DARC data radio channel 

DARPA Defense Advanced Research Projects Agency (US) 

DARS Digital Audio Radio Service (satellite broadcast) 

DAS distributed antenna system (can be active or passive) 

DASB Defence Aviation Safety Board (UK) 

DASC Defence Aviation Safety Centre (UK - Bentley Priory) 

UK tri-Service formed in 2002 to develop, regulate and audit policy. 

DASS Distress Alerting Satellite System (US) 

DAT digital audio tape (holds 700 MB to 2.3 GB of data) 

Datatrak proprietary navigation system (Siemens UK) 

Coherent LF DTMA navigation system giving an accuracy

DBF digital beam-forming (antenna) 

dBi decibels, isotropic 

DBTF database terrain following 

dBW decibel watts (power level relative to 1 watt) 

DCB differential code bias (eg of a GPS satellite) 

DCDB Data Centre on Digital Bathymetry 

DCE data cercuit-terminating equipment 

DCN document change notice 

DCPC direct controller/pilot communications 

DCPS differentially corrected positioning service 

DCT direct 

DCW Digital Chart of the World (1:1M air nav chart from US DMA) 

DD double-differencing (GNSS relative positioning) 

DDC delays, diversions and cancellations 

DDC digital down-convertor 

DDF divided difference filter 

DDG dispatch deviation guide (associated with MEL) 

DDGI German unbrella organisation for geoinformation 

DDM difference in depth of modulation 

DDR demand data repository 

DDR detailed design review 

DDRC Diving Diseases Recompression Chamber (Poole, UK) 

DDV Design, Development and In-Orbit Validation (phase of Galileo) 

dead ahead direction ahead of a (ship’s) fore-and-aft line 

Dec declination 

Decca hyperbolic LF navigation system 

In UK funded by THLS until 31 Mar 00. 

DECT Digital European Cordless Telecommunications 

Short range speech or data system. TDMA on 1.88-1.90 GHz. 

DEFRA Department for the Envirnonment, Food and Rural Affairs (UK) 

deg degrees 

DELTA Specification for vehicle DSRC modules and OBTs (EC) 

DEM digital elevation model/map (for charting etc) 

Demeter Digital Electronic Mapping of European Territory 

Covers data standards for road networks for nav systems. 

Dep departure 

Distance between 2 meridians at any given parallel of latiude, 

expressed in nautical miles. 

DERA Defence Evaluation and Research Agency (UK) 

On 1 Apr 01 split into New DERA and the Defence Science and 

Technology (DST) Lab. New DERA becomes ‘QinetiQ’ on 2 Jul 01. 

DES Data Encryption Standard 

33 

March 2012

Dest destination 

DETR Department of the Environment, Transport and the Regions (UK) 

Ceased in Jun 01 - most became DTLR. 

Dev deviation 

Angle between MN and CN, from MN eastwards named E (+), 

westwards named W (-). 

DF direct to a fix 

DFDAU digital flight data acquisition unit 

DFDR digital flight data recorder 

DFDRS digital flight data recording system 

DFGC digital flight guidance computer 

DFGS digital flight guidance system 

DFHRS Digital Finite Element Height Reference Surface (German HRS) 

DFIS Digital Flight Information Services 

DFS Deutsche Flugsicherung GmbH (German ATSP) 

DfT Department for Transport (UK) 

DFTI distance from touchdown indicator 

DG degaussing 

DG directional gyro 

DG Director-General 

D G 

distance between 2 points on a great circle (orthodromic distance) 

DG MARE Directorate-General for Maritime Affairs and Fisheries (EU) 

DG Range degaussing range 

DG TREN Director General TRansport and ENergy (EC, ex-DG VII, now MOVE) 

DGAC Direction Général a l’Aviation Civile (French CAA) 

DGLONASS Differential GLONASS 

DGNSS Differential GNSS 

DGON Deutsche Gesellschaft für Ortung und Navigation e.V. 

German Institute of Navigation. 

DGPS (or D-GPS) Differential GPS 

DGS data gathering station 

DGT digital GPS translator (of TGRS) 

DH decision height (of landing aircraft referenced to terrain) 

Height above runway at which pilot must have runway approach lights in 

sight or initiate the missed-approach procedure. 

DHS Department of Homeland Security (US) 

DI direction indicator 

DIA detection, identification and adaptation 

differential 

system 

An augmentation system whereby radionavigation signals are monitored 

at a known position and the corrections so determined are transmitted 

to users in the coverage area. 

DIN Deutsches Institut für Normung e.V. (German standards body) 

34 

March 2012

DINGPOS Demonstrator for Indoor GNSS Positioning 

Highly-sensitive GPS/Galileo rx for indoors with added posit’ing. 

DIP dual in-line package (chip) 

DIRECTS Demo of Interoperable R’d user End-to-end Charging &Telematics 

DIS Draft International Standard (ISO) 

DIS Driver Information System 

dist distance 

DIUS Department for Innovation, Universities and Skills (UK) 

DIW dead in water 

DJF design justification file (eg EGNOS) 

DL datalink 

D L 

distance between 2 points on a rhumb line (loxodromic distance) 

DLat difference in latitude 

DLL delay locked loop 

DLong difference in longitude 

DLORAN Differential LORAN 

DLR Deutsches Zentrum fur Luft-und Raum-Fahrt 

German National Space Agency. 

DLT digital linear tape 

DMA Defense Mapping Agency (US)(now NIMA) 

DMC digital magnetic compass 

DMC digital management computer 

DME distance measuring equipment 

DMEAN Best-practice in current ATM (precursor to SESAR) 

DMP difference of meridianal parts 

DMS dimethyl sulphide 

Produced by phytoplankton in response to zooplankton grazing - its 

odour attracts some birds, enabling them to navigate to food-rich 

sources. 

DNA Direction de la Navigation Aérienne (French ATSP) 

DNC digital nautical chart 

DNF Digital National Framework (OS) 

DNS Decca Navigator System (withdrawn in UK 31 March 2000) 

DNS Domain Name System (converts TCP/IP to web address) 

DNV Det Norske Veritas (classification society) 

DOA direction of arrival (method of Cellphone positioning) 

DOC Department Of Commerce (US) 

DoD Department of Defense (US) 

Dolphin A UK TETRA system 

DOMNR Department of Marine and Natural Resources (Ireland) 

35 

March 2012

DOP dilution of precision 

A dimensionless number that accounts for the contribution of relative 

satellite geometry to errors in position determination. 

DORIS Doppler Orbitography and Radiopositioning by Satellite 

DOT Department of Transportation (US) 

DOTIS (D-OTIS) Digital Operational Terminal Information Service (air) 

DP dew-point 

DP dynamic positioning 

DPDR delta preliliminary design review (Galileo) 

dps degrees per second (eg in gyro spec) 

DPS dynamic positioning system 

DQI Digital Quartz Inertial Measurement Unit (Boeing, US) 

DQM data quality monitoring 

DR dead (deduced) reckoning 

DR drifting (met) 

DRA digital radio-altimeter 

DR cor 

corrected DR position 

Estimated position obtained by adding to the last fix course (track) 

and speed. 

DRG digital route guidance 

DRI driver restriction information (eg info on blocked roads) 

Drift angle Angular difference between: (Sea) course of advance and course 

through water; (Air) heading and track. 

DRISL Data Relay Inter-Satellite Links (part of WSN) 

DRIVE Dedicated Road Infrastructure for Vehicle Safety in Europe (EU) 

Also known as ‘Driving Implementation and Evaluation of C2X 

Communication Technology in Europe (DRIVE C2X)’. 

DRL data relay link (eg between satellite and ground) 

DRL daytime running light (vehicle) 

DRM data resource management (comms) 

DRM digital road map 

dRMS distance root-mean-square 

The root-mean-square of the radial distances from the true position to 

the observed positions obtained from a number of trials. 

DRN data radio network 

DRS dead reckoning system 

DRS differential reference station 

DRT demand responsive transport (small buses etc) 

DS duststorm (met) 

DS-CDMA direct-sequence code-division multiple access 

DS-UWB direct-sequence UWB 

DSAC Direction de la Sécurité de l’Aviation Civile (France) 

36 

March 2012

DSB Defense Science Board (US) 

DSB double sideband 

DSC Dangerous Goods, Solid Cargoes and Containers (IMO) 

DSC digital selective calling (GMDSS) 

DSC dynamically supported craft 

DSI detailed spectrum investigation 

DSLAM digital subscriber line access multiplexer (local for wideband users) 

DSM digital surface model (for charting) 

DSMAC digital scene matching area correlation (navigation technique) 

DSN Deep Space Network 

DSNA-DTI Direction de la Technique et de l'Innovation 

. . des Services de la Navigation Aérienne. 

DSP digital signal process(ing)(or) 

DSRC dedicated short-range communication (system) 

DSS decision support system 

DSS Digital Signal Standard (eg VHF data link RSA-DSS). 

DSSR Digital Short-Range Radio 

Direct connection between hand-portables over short distances. 

Typically use 880-890 and 933-935 MHz. 

DST data storage tag (used to record eg depth profiles of tagged fish) 

DST daylight saving time 

Dstl Defence Science and Technology Laboratory (UK - ex-DERA) 

Formed on 1 Apr 01 as the defence arm of what was DERA. 

DSTO Defence Science and Technology Organisation (Australia) 

DSV diving support vessel 

DT&E Development Test and Evaluation (comes before OT&E) 

DTE data terminal equipment 

DTED digital terrain elevation data(base) 

DTEO Defence Test and Evaluation Organisation (Division of DERA) 

DTG distance to go 

DTG dynamically tuned gyro 

DTI Department of Trade and Industry (UK) 

DTLR Department for Transport, Local Government & the Regions (UK) 

Formed from DETR in Jun 01. Now DfT. 

DTM digital terrain model/map 

DTOA difference in time of arrival (of events in 2 signals) 

DTS Digital Terrain System 

Predictive GPWS for military ac. 

DTT digital terrestrial television 

DU display unit 

DU dust (met) 

DUA dedicated user area (ATC) 

37 

March 2012

duplex use of separate radio channels for transmission and reception 

DUT1 value of predicted difference between UTC and UT1 

DVB digital video broadcast(ing) 

DVB-H digital video broadcasting for handhelds (standard for mobiles) 

DVD digital versatile disc 

Initially stood for ‘digital video disc’. Holds up to 17 Gigabytes. 

DVI direct voice input (eg cockpit) 

DVOR doppler VOR 

DVP Development Verification Platform (EGNOS) 

DWT (Dwt) deadweight tonnage 

DX.90 Format for digital cartographic data 

DZ drizzle (met) 

DZ dropping zone (parachutes) 

E-112 Enhanced 112 (inc automatic location of European mobile phones) 

E-119 Enhanced 119 (Japanese emergency no (= E112 or E-911) 

E-911 Enhanced 911 (inc automatic location of US mobile phones) 

Requires handset location to 150m (95%). 

E-band NATO radar band 2-3 GHz = 15-10 cm 

E-Call emergency call (GTP) 

E-CID Enhanced Cell ID (mobile phones) 

e-CMID Electronic Common Marine Inspection Document (IMCA) 

E-field electric-field (eg of aerial) 

E-LORAN Enhanced LORAN 

Modern transmitters & receivers giving all-in-view operation and 

carrying GNSS overlay data. Better than 20 m and 40 ns. 

E-MERGE ERTICO project for pan-European vehicle emergency call services 

Project completion March 2004. 

e-Navigation The harmonised creation, collection, integration, exchange and 

presentation of maritime information onboard and ashore by 

electronic means to enhance berth-to-berth navigation and 

related services, for safety and security at sea and protection 

of the marine environment (IMO). 

E-Navigator Single interface to organise, update, and unify all UKHO’s paper 

and digital info, inc tide and weather info. 

E-OTD enhanced observed time difference (100m accuracy from cellph’n) 

E1, E2 etc Galileo carrier frequencies 

Frequencies (MHz) are 1,590 (E1), 1,563 (E2), 1,216 (E3), 1,260 (E4), 

1,176 (E5A = GPS L5), 1,201 (E5B) and 1,280 (E6). 

E112 European requirement to provide location of emerg calls fm mobiles 

E2PROM electrically erasable programmable read-only memory 

E911 US requirement to provide location of emerg calls from mobiles 

38 

March 2012

EA (EA13) Euro Area (Jan 07) 

Austria, Belgium, Finland, France, Germany, Greece, Ireland, 

Italy, Luxembourg, the Netherlands, Portugal, Slovenia, Spain. 

EAAP European Association for Aviation Psychology 

EAD European Aeronautical Information Services Database 

Operational since Jun 03, provides a complete and up-to-date 

worldwide reference of quality-assured aeronautical information. 

EADI electronic attitude director indicator 

EADS European Aeronautic, Defence & Space Co 

EAG European ATFM Group (EUROCONTROL) 

EAL Echelle Atomique Libre (Free Atomic Time) 

The weighted mean of >260 international atomic clocks. 

EANPG European Air Navigation Planning Group (ICAO) 

EARSC European Association of Remote Sensing Companies 

EAS equivalent airspeed 

EASA European Aviation Safety Authority (EU - operational on 28 Sep 03) 

EASP European Aviation Safety Programme (EU) 

EAT estimated (or expected) approach time 

EATCHIP European ATC Harmonisation and Integration Prog (EUROCONTROL) 

EATMP European Air Traffic Management Programme (EUROCONTROL) 

EATMS European Air Traffic Management System 

Under EUROCONTROL's ATM2000 initiative. 

EBCDIC extended binary-coded decimal interchange code (8-bit) 

EBL electronic bearing line (radar) 

EBL Evolved Baseline (part of US National PNT Architecture) 

EBM electronic bearing marker 

EBOM (E-BOM) electronic bill of material 

EBU European Broadcasting Union 

66 member states in Europe and Mediterranean area plus 51 associate 

member states. 

EC European Commission 

ECA European Cockpit Association 

ECA European Common Frequency Allocation Table 

ECAA European Common Aviation Area (part of SES) 

ECAC European Civil Aviation Conference (42 European states in 2006) 

eCall Pan-European in-vehicle emergency call system (mandatory by 2015?) 

ECAM electronic centralised aircraft monitor 

ECASBA EU Association of Shipbrokers and Agents 

ECC electronic chart centre 

39 

March 2012

ECCG Experimental Centre Consultation Group (EUROCONTROL) 

ECD envelope-to-cycle delay (eg LORAN) 

ECDIS electronic chart display and information system 

Hardware and sofware that can display ENC data. 

ECEF earth-centred earth-fixed (coordinate frame) 

ECI earth-centred inertial (reference frame) 

ECINS electronic charting and integrated navigation system 

ECIP European Convergence and Implementation Plan (air) 

ECLAYR EGNOS Continuous Logging AnalYseR 

ECOMM European Conference on Mobility Management (EU) (eg ECOMM ‘97) 

eCompass electronic compass (usually solid-state) 

eConvoy Auomatic close separation between cars (to increase road occupancy) 

= Platooning or eTow-bar. 

ECOTTRIS European Collaboration on Transition Training for Improved Safety 

EC air transport (ATM) safety project to ensure that the human 

element is adequately trained for technical innovations, especially the 

‘glass cockpit’. 

ECP Engineering Change Proposal 

ECP European Common Proposal (for WRC) 

ECPINS Electronic Chart Precise Integrated Navigation System (US) 

ECR European Central Repository (EASA - for air occurrences) 

ECS electronic chart system 

ECSA European Community Shipowners’ Association 

ECTAA European Travel Agents and Tour Operators Associations 

Founded 1961, all EU states + Norway + Switzerland. Based Brussels. 

ECU electronic control unit (in vehicle) 

ED emission delay (of LORAN slave station = coding delay + transit time) 

ED European Datum 

Most commonly used is ED-50 (of 1950). This uses a non-geocentric 

geoid to express latitude & longitude within Europe. 

EDA European Defence Agency 

EDAS EGNOS Data Access System 

EDC early display configuation 

EDGE Enhanced Data-rate for GSM Evolution (mobile phones) 

EDI electronic data interchange 

EDM electronic distance measurement 

EDPG European Data Producers’ Group 

EDR event data recorder (vehicle) 

EDR excessive descent rate (TAWS alert) 

EDRM European digital road map 

EDU electronic display unit 

EE external ephemeris (file, eg for A-GNSS) 

40 

March 2012

EEA European Economic Area 

EEA European Environment Agency 

EEIG European Economic Interest Group (for ERTMS) 

EELV Evolved Expandable Launch Vehicle (USAF - covers GPS launches) 

EET estimated elapsed time 

EETES EGNOS End-to-End Simulator 

EETS European Electronic Toll Service 

EEZ exclusive economic zone 

EFB electronic flight bag (replaces paper charts & documentation) 

EFC electronic fee collection (includes ERP, ETC, RUC etc) 

EFCS electronic flight control system 

EFDR electronic flight data recorder 

EFF Electronic Flight Folder (software for EFB) 

EFI external functionality interface (Telematics Forum WAP interface) 

EFIS electronic flight instrument system 

EFT European Transport Workers' Federation 

EFT extended function timer 

EFTF European Frequency and Time Forum 

EGAS European Guaranteed Access to Space (ESA programme) 

Support for European launch service (2005-09). 

EGAST European General Aviation Safety Team 

EGATS European Guild of Air Traffic Services 

EGC enhanced group calling (eg Inmarsat) 

EGDOP extended geometric dilution of precision 

EGI embedded GPS inertial (eg US GPS JPO programme) 

EGII European Geographic Information Infrastructure 

EGIS European Conference on GIS 

EGNOS European Geostationary Navigation Overlay Service 

Space-based augmentation system providing augmentation to GPS and 

GLONASS. Initial ops 2009; full ops due in 2010. 

EGPS Enhanced GPS 

EGPWS Enhanced Ground Proximity Warning System 

EGR embedded GPS receiver 

EGS European Geophysical Society (Katlenberg-Lindau, Germany) 

EGS European GNSS Secretariat (to the ETG) 

EHF extremely high frequency (30-300 GHz) 

EHMA European Harbour Masters’ Association 

EHS enhanced surveillance mode SSR (Enhanced Mode S) 

Aircraft identification, airspeed, altitude,vertical velocity + other info 

via SSR Mode S. 

EHSI electronic horizontal situation indicator 

EIDS European Integrity Determination System 

41 

March 2012

EIFS Advanced Integrated Fare System (Motorola smart card system) 

EIRP (eirp) equivalent isotropically radiated power 

Theoretical measure of power of a transmitter that radiates equally in 

all directions. Usually in dBW. 

EIV errors in variables 

EJN European Journal of Navigation (DGON, NIN & NNF) 

EKF extended/enhanced Kalman filter 

ELA European Light Aircraft 

ELBA Emergency Location Beacon, Aircraft (ELT) 

ELFAA European Low Fares Airline Association 

ELL electrosensory lateral line lobe (of fish brains) 

ellipsoid A solid of which all plane sections through one axis are ellipses 

and all other plane sections are ellipses or circles. 

ELM extended length message (ATC Mode S) 

eLORAN (eLoran) Enhanced LORAN 

ELOS extended line-of-sight 

ELRM Enhanced LBS Reference Model 

ELRR Enhanced Loran Reference Receiver (Symmetricom) 

ELS elementary surveillance (aircraft identification via SSR Mode S) 

ELS Ensemble de Lancement Soyuz (at EU Spaceport, French Guiana) 

ELT emergency location terminal 

ELT emergency location transmitter 

Transmitter fixed to aircraft which transmits on emergency 

frequencies on impact or immersion. 

ELTIS European Local Transport Information Service (EU) 

Can be found at www.eltis.org. 

EM electromagnetic 

EM engineering model 

EMC electromagnetic compatibility 

Ability of equipment or systems to be used within designated 

environments without causing or receiving electromagnetic 

interference. 

EMCA European Maritime Core Area 

EMCON emission control 

EMDA East Midlands Development Authority 

EMEA Europe, Middle East and Africa (ICAO area) 

EMEC European Maritime Equipment Council 

emf electromotive force 

EMI electromagnetic interference 

EMILY Project for the hybridisation of satellite and cellular positioning (EC) 

Completion Dec 04. 

EMP electromagnetic pulse 

42 

March 2012

EMPA European Maritime Pilots’ Association 

EMRF European Maritime Radionavigation Forum 

Independent body formed December 1999 from the European GNSS 

Maritime Advisory Forum. 

EMRP equivalent monopole radiated power 

EMS EGNOS Message Server (archive of EGNOS broadcasted messages) 

EMSA European Maritime Safety Agency (EC - formed in 2002 post-’Erika’) 

EN Européen Normalisation (European Standard) 

ENAC Italian CAA 

ENAV Ente Nazionale di Assistenza al Volo (Italian ATSP) 

ENC electronic navigational chart 

Data is held as vectors and can be selectively displayed. When 

produced to IHO/IMO standard S57 Ed 3 the data is legally 

equivalent to a paper chart for vessels subject to SOLAS regulations. 

ENC electronic noise cancelling 

ENC European Navigation Conference 

ENISA European Network and Information Security Agency 

ENMA EGNOS Network Management Application 

ENoLL European Network of Living Labs (EU) 

ENRI Electronic Navigation Research Institute (Japan) 

ENS electronic navigation system 

ENSO El Niño/Southern Oscillation 

ENT EGNOS Network Time 

ENU East-North-Up (system of defining coordinates) 

ENVISAT Environmental Satellite (ERS follow-on) 

EO earth observation (from space) 

EO electro-optics 

EO2HEAVEN Earth Observation and ENVironmental modelling for the mitigation of 

HEAlth risks 

EOBR electronic on-board recorder (vehicles) 

EOD electric organ discharge (typically of fish) 

EOG EGNOS Operators’ Group 

Alliance between ATS providers of France, Germany, Italy, Spain and 

UK which are contributing to the EGNOS project. 

EOIG EGNOS Operations and Infrastructure Group 

Consortium of EU aviation administrations. 

EOR end-of-record (often 9999) 

EOR Extent of the Realm (for UK, the land within limit of mean low water) 

EOSI Earth Observation Science Initiative (NERC) 

EOTD enhanced observed time difference (cellphone location technique) 

Could give accuracy of

EOW end-of-week 

In GPS occurs approx midnight each Sat/Sun. Week no. defined by 10bit 

word and hence rolls-over to zero after each 1,024 weeks from 6 

Jan 80. First roll-over was 22 Aug 99. 

EP electronic protection (EW to ensure friendly use of spectrum) 

In GPS to ensure use in higher J/S ratios and intermittent access. 

EP estimated position (most probable position) 

Most probable position obtained by adding to the last fix course 

(track) and speed, considering all estimated influence. (After ISO) 

EP European Parliament 

EPA electronic plotting aid 

EPF energy-per-fix (eg in a GPS receiver) 

EPFD equivalent power flux density 

EPFS electronic position-fixing system 

EPGS electrical power generation system (aircraft) 

EPIC European Positioning, Navigation and Timing Industry Council 

Forum for organisations with an interest in all PNT systems inc GNSS. 

EPIRB Emergency Position-Indicating Radio Beacon 

EPN EUREF Permanent Network 

Selection of European permanent GPS tracking stations. Central 

Bureau in Brussels. 

EPNdB effective perceived noise decibel 

EPO EGNOS Project Office 

EPOMM European Platform on Mobility Management (EU) 

EPR electron paramagnetic resonance 

EPROM erasable programmable read-only memory 

EPS ECDIS Perfomance Standard (IMO) 

EPS Encapsulated Postscript (graphic file format) 

EPS EUMETSAT Polar System (operational met & climate monitoring) 

Comprises 3 Metop satellites. 

EPSRC Engineering and Physical Sciences Research Council (UK) 

EPVS electronic plotting video symbols (maritime) 

EPZ enhanced procedures zone (air) 

EQM electrical qualification model 

Equator primary great circle of the earth 

equatorial angle angle along the equator in the direction of earth rotation 

ER extended range 

ERA earth rotation angle 

ERA European Regional Airlines Association 

ERA European Research Area 

ERAA European Regional Airlines Association 

ERAM En Route Automation Modernisation (US FAA) 

44 

March 2012

ERASMUS A EC exchange programme for students in 31 European countries 

to study for part of their degree in another country. 

ERBL electronic range and bearing line (radar) 

ERC en-route chart 

ERC European Radiocommunications Committee 

ERD estimated range deviation (GPS) 

Diff between the current MCS Kalman Filter state estimate for the 

satellite's position and the satellite's position as broadcast in the 

Navigation Data, along the path between the receiver and the satellite. 

ERDM equation restore difference method (eg for DGPS) 

ERF European Union Road Federation (part of IRF) 

ERG Economic Regulation Group (UK CAA) 

ERGS electronic route guidance system 

ERIC European Road Information Centre 

ERIC3000 is system for cross-border sharing of dynamic and semistatic 

road info. 21 nations and 100,000 km of European roads. 

ERNP European Radionavigation Plan 

ERO European Radiocommunications Office (of the ERC) 

Based in Copenhagen. www.ero.dk. 

EROPS extended range operations (aircraft) 

ERP effective radiated power 

The product of power and gain of a transmitting aerial in a particular 

direction. 

ERP electronic road pricing (a form of EFC) 

ERP enterprise resource planning 

ERRI European Rail Research Institute (based in Uttrecht, NL) 

ERRV Emergency Response and Rescue Vessel 

ERRVA Emergency Response and Rescue Vessel Association 

Was the SSOA until May 2000. 

ERS En Route Supplement (for aircrew) 

ERS European Remote Sensing satellite 

ERTICO Euro Road Transport Telematics Implementation Coord Organisation 

Not-for-profit coordinating body based in Brussels. Custodian of the 

GATS Forum. www.ertico.com 

ERTMS European Rail Traffic Management System (EU) 

ETCS + GSM-R + ETML + HEROE. 

ES electronic support (form of EW) 

ES environmental surveillance 

ES Extended Squitter (Mode S 1,090 MHz) 

ESA electronic sub-assembly 

45 

March 2012

ESA European Space Agency 

Inter-government body promoting European space technology for 

peaceful applications. Formed 1974. Comprises (2010) Austria, 

Belgium, Czech Rep, Denmark, Finland, France, Germany, Greece, 

Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, 

Sweden, Switzerland & UK. Canada is an Associate Member. 

ESAF Eastern and Southern African Office (ICAO) 

eSafety EU initiative for in-vehicle systems (established 2001) 

ESARR EUROCONTROL Safety Regulatory Requirements 

ESD electro-static discharge 

ESDI European Spatial Data Infrastructure 

ESDP European Security and Defence Policy 

eSDS Electronic Safety Data Sheet (marine) 

ESERO European Space Education Resource Office 

ESGN electrically-suspended gyro navigator 

ESIG ECDIS security internet gate 

ESNC European Satellite Navigation Competition (ESA) 

ESNIS European Satellite Navigation Industries (was Galileo Industries) 

Owned by Alcatel Alenia Space SAS (FR), Finmeccanica SpA 

(IT), EADS Astrium GmbH (GE), EADS Astrium Ltd (UK), Galileo 

Sistemas y Servicios (7 companies fm SP) & 3 Thales subsidaries. 

ESNP European Satellite Navigation Programme (ETG) 

ESOC European Space Operations Centre 

ESoP European Statement of Principles 

ESP European Space Policy 

ESPI European Space Policy Institute 

ESPO European Sea Ports Organisation 

ESRG Electronic Systems Research Group (Brunel University) 

ESRO European Space Research Organisation 

ESSF EGNOS System Simulation Facility 

ESSI European Strategic Safety Initiative 

Aviation safety partnership between EASA, regulators and industry. 

ESSP European Satellite Service Provider 

Created in April 2001 to operate EGNOS. Shareholders are 

NATS (UK), DGAC/DSNA (F), AENA (E), ENAV (I), DFS (D), 

NAV-PT (P) and Skyguide (CH). 

ESTB EGNOS System Test Bed 

ESTEC ESA Technical Centre (Navigation Lab at Noordwijk, Netherlands) 

ESTMP European Space Technology Master Plan 

ESV earth station (located on a) vessel (for maritime comms) 

ESV EGNOS signal-in-space validation 

ESVS EGNOS Service Volume Simulator 

ETA estimated time of arrival 

46 

March 2012

ETACS Extended Total Access Communication System (cellphone standard) 

ETC electronic toll collection (a form of EFC) 

ETCS European Train Control System (part of ERTMS) 

Internationally Interoperable signalling and safety system. 

3 funtional levels. 

ETD estimated time of departure 

ETE estimated time en route 

eTEN Electronic Trans-European (Transport) Networks (EU programme) 

ETF European Transport Workers’ Federation 

ETG European Tripartite Group 

Was a cooperation between EC, ESA and EUROCONTROL to develop 

EGNOS and perform preliminary work on GNSS-2. 

ETML European Traffic Management Layer (part of ERTMS) 

ETOPS extended-range twin-engine operations 

eTow-bar Auomatic close separation between cars (to increase road occupancy) 

= Platooning or eConvoy. 

ETRF European Terrestrial Reference Frame 

Almost identical to WGS-84, but accommodates European continental 

drift. 

ETRO estimated time to return of operations (eg of GPS satellite) 

ETRS89 European Terrestrial Reference System 1989 

ETS Emissions Trading Scheme (EU) 

ETS European Telecommunications Standard 

ETSI European Telecommunications Standards Institute 

ETSO European Technical Standard Order (air) 

ETV emergency towing vessel 

EU (EU27) European Union (27 states) 

Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, 

Finland, France, Germany, Greece, Hungary, Irish Republic, Italy, 

Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, 

Romania, Slovakia, Slovenia, Spain, Sweden & UK. 

EU ETS European Union Emissions Trading Scheme 

EUCAR European Council for Automotive R&D 

EUFRANET European Freight Railway Network (EU) 

EUGIN European Group of Institutes of Navigation 

Institutes (2010): Austria, Czech Rep, France, Germany, Italy, 

Netherlands, Nordic, Poland, Portugal, Spain, Switzerland, UK. 

Eumetsat European Organisation for the Exploitation of Met Satellites 

17 European member states, formed in 1986 to run op met satellites. 

EUPOS European Position Determination System 

EUR European Region (of ICAO) 

EURAN European Radionavigation Systems and Services (DGON conf series) 

EUREF Reference Frame Sub-Commission for Europe (IAG - created ED-50) 

47 

March 2012

EUREKA Coordinated EU R&D programme for collaboration between industries 

Eureka 147 A standard for digital audio broadcasting 

Eurely Consortium bidding for Galileo concession 

Alcatel, Finmeccanica & Vinci Concessions & Capgemini. 

Eurisy Paris-based European non-profit organisation whose members are 

space agencies or governmental offices in charge of space affairs in 

Europe, and international organizations dealing with space matters. 

Euro NCAP European New Car Assessment Programme (Brussels-based) 

EUROAT Body to harmonise national rules for OAT under IFR inside controlled 

airspace on European level. 

EUROBALISE Use of magnetic transponders (balises) for comms between track and 

train. Part of ETCS. 

EUROCAE European Organisation for Civil Aviation Electronics 

EUROCONTROL European Organisation for the Safety of Air Navigation 

Albania, Armenia, Austria, Belgium, Bosnia & Herzegovina, Bulgaria, 

Croatia, Cyprus, Czech Rep, Denmark, Finland, France, Germany, 

Greece, Hungary, Ireland, Italy, Lithuania, Luxembourg, Macedonia, 

Malta, Moldova, Monaco, Montenegro, Netherlands, Norway, Poland, 

Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, 

Switzerland,Turkey, Ukraine and UK. (2010) 

Eurofix Datalink system whereby GNSS differential and integrity data is 

transmitted by Loran-C, eLoran and Chayka. 

EuroGeographics Represents 46 organisations from 41 countries of European 

National Mapping and Cadastral Agencies (NMCAs). 

EUROGI European Umbrella Organisation for Geographic Information 

EUROLOOP semi-continuous transmission system for trains (part of ETCS) 

Europrice EC DG VII (TREN) project for deployment of road pricing in Europe 

Linked to Intercept Project. 

EURORADIO Based on GSM-R, will replace optical train signalling (part of ETCS) 

EuroRAP European Road Assessment Programme 

EUROSCOPE Efficient Urban Transport Ops Services Co-op of Port Cities in Eur 

Development of ROMANSE and SCOPE. 

EUROSUR European Border Surveillance System 

EUSC European Union Satellite Centre (Torrejón de Ardoz, Spain) 

EUT equipment under test 

EUTELSAT European Telecommunications Satellite Organisation 

EUTELTRACS European Telecommunication and Tracking System 

EUTM Emergency Unusable Time (NELS Loran-C - see also UTM and AUTM) 

Scheduled and authorised UTM but with less than 72 hrs of notice. 

EUTP European Transfer Point (for intermodal transport)(EU) 

EV Eigenvalue 

EVA autonomous route guidance system from Robert Bosch 

EVI electronic vehicle identification (also EC DG TREN project) 

EVIS Electronic Vehicle Identification System (chip fitted to every car) 

48 

March 2012

EVS enhanced vision system 

EVSC External Vehicle Speed Control (MIRA project 1997-2001, now ISA) 

EW Electronic Warfare 

EWAAS End-State WAAS 

Final stage of WAAS, capable of supporting navigation and CAT I 

precision approach. 

EWAN EGNOS Wide Area Network 

EWG evil waveform generator 

EXM executive monitoring (GBAS processing) 

Expandable-24 Reconfiguration for GPS constellation to use >30 sats (by mid-2011) 

f Earth’s flattening (typically 1/298) 

f femto (SI unit multiplier of 10 -15 ) 

f frequency 

F-a farad (capacitance) 

F-band NATO radar band 3-4 GHz = 10-7.5 cm 

F, ºFahrenheit 

FA fix to an altitude 

FAA Federal Aviation Administration (US) 

FAA Fleet Air Arm (RN) 

FAB fast adaptable bandwidth (of loop filter for tracking GPS signals) 

FAB functional airspace block (ignores national boundaries - part of SES) 

FABA Functional Airspace Block Approach (part of SES) 

FADEC full-authority digital engine control 

FAF final approach fix 

FAI Fédération Aéronautique Internationale 

Body for verification of aeronautical record attempts and sporting 

activities. 

failure The unintended termination of the ability of a system, or part of a 

system, to perform its required function. 

failure rate The average number of failures of a system, or part of a system, per 

unit time. 

FANG Flight Management System Air Traffic Management Next Generation 

FANS Future Air Navigation System (ICAO) 

FANS-1/A air-to-ground datalink (ICAO) 

FAR Federal Air Regulation (US) 

FASS FAst Ship Safety (EU Framework project) 

FAST Final Approach Sequencing Tool (for air traffic)(US) 

FASTEST Facilitating Smart Card Technology for Electronic Ticketing & 

Seamless Travel 

FASTI First Air Traffic Control Support Tools Implementation 

EUROCONTROL concept to provide additional ATC capacity. 

FAT factory acceptance check 

49 

March 2012

FAT final approach track 

FAT free air temperature 

FATDMA fixed allocation time division multiple access 

FAU fast acquisition unit (rx) 

FAWP final approach waypoint 

FB FleetBroadband (Inmarsat) 

FBAR film bulk acoustic resonator (filter) 

FBG fibre Bragg grating (type of accelerometer for solid-state IMU) 

FBW fly-by-wire 

FC funnel cloud (met) 

FCC Federal Communications Commission (US) 

FCC flight control computer 

FCC fully cellular containership 

FCD floating car data (from ‘probe’ vehicles that can create mapping data) 

FCL flight crew licensing 

FCO financed, constructed and operated 

FCS Federation of Communications Services (UK) 

Fcst forecast 

FCU flight control unit 

FD fault (failure) detection (algorithm) 

FD flight director 

FDA flight data analysis 

Use of FDR data to monitor quality of operations. 

FDAU flight data acquisition unit 

FDC France Developpement Conseil (involved with Galileo) 

FDDI fibre distributed data interface 

FDE fault (failure) detection and exclusion 

FDI fault/failure detection and isolation 

FDIR failure detection , isolation and recovery 

FDM flight data monitoring (FOQA in US) 

The use of an electronic flight data recorder to routinely monitor crew 

performance (not jus when an incident occurs). Mandatory in Europe 

(>27,000 kg) from 2004; is voluntary in US. 

FDMA frequency division multiple access 

FDP Flight Dynamics Facility (Galileo) 

FDP(S) flight data processing (system) 

FDPS flight data processing system 

FDR flight data recorder 

FDRS flight data recorder system 

FDU flux detector unit 

FDX full duplex 

FEC forward error correction 

50 

March 2012

FEE front end equipment 

FEI Federation of Electronics Industries (UK) 

Changed name to ‘INTELLECT’ in 2002. 

FEM finite element mesh 

femtocell Small cellular base station, typically for home or small business ~10 m 

Fengyun (also FY) Chinese metsats (means ‘wind and cloud') 

FERNS Far East RadioNavigation System 

LORAN-C and Chayka system similar to NELS. 

FET field effect transistor 

FEW few clouds (1-2 oktas) 

FF fault free 

FFI Norwegian Defence Research Establishment 

FFL fixed and flashing light 

FFM far field monitor 

FFSK fast frequency-shift keying 

FFT Fast Fourier Transform 

FG fog (met) 

FGDC Federal Geographic Data Committee (US) 

FGMU Frequency Generation and Modulation Unit (Galileo) 

FHA functional hazard assessment/analysis 

FHWA Federal Highway Administration (US) 

FIATA International Federation of Freight Forwarders Associations 

FIB flying infalatable boat (a RIB under a microlight wing) 

FIBE Fully Internet Based ESTB 

FIC Flight Information Centre 

FID Field Identifying Number (for farming, created in UK in 1995) 

FIG Fédération Internationale des Géomètres 

International Federation of Surveyors. 

FIR Flight Information Region 

Firewire Computer connection at up to 400 Mbps (IEEE-1394) 

FIS Field Identification System (of farming maps) 

FIS Flight Information Service (ATC) 

FISG Fishing Industry Safety Group 

FISO Flight Information Service Officer 

fix A position established by processing information from a number of 

navigation observations. Determined without reference to any other 

former position. 

fix interval Maximum time between fixes. 

fix rate The number of fixes per unit time. 

FIX_8 Decimetre-level positioning project using a stand-alone GNSS rx 

using only free-to-air signals (GJU). 

FKP Flächen Korrektur Parameter (in RTK to calculate area corrections) 

51 

March 2012

FL flight level 

Altitude expressed in hundreds of ft, with ISA pressure setting of 

1013.2mb set on altimeter. 

FLARM Flight alarm system for gliders 

Uses position and movement info from embedded GPS and altitude 

sensor which is transmitted over short-range radio to other FLARM 

aircraft. Displays the position of other FLARMs and audio warnings. 

FLAS Flight Level Allocation Scheme 

FLIP Flight Information Publication 

FLIR forward-looking infrared 

FLL frequency-locked loop 

FLPFM foot-launched powered flying machine 

flt flight 

FLTA forward looking terrain avoidance (eg TAWS) 

FM faulty mode 

FM flight model 

FM frequency modulation 

FM from (met) 

FMC fixed-mobile convergencenew (using a dual-mode phone handset) 

FMC flight management computer 

FMCS flight management computer system 

FMEA failure modes and effects analysis 

FMECA failure mode effects criticality analysis 

FMES failure modes and effects summary 

FMG Frequency Management Group (ICAO) 

FMGS flight management and guidance system 

FMOD fuzzy model 

FMS fleet management system 

FMS flight management system 

FMSP flight mode selector panel 

FNPT flight and navigation procedure trainer 

FO fibre optic 

FO fuel oil 

FOA frequency-of-arrival 

FOC Final Operating Capability (WAAS - by Dec 2007) 

FOC flag of convenience 

FOC Full Operational Capability 

For GPS defined as 24 Block II/IIA satellites operating in assigned 

orbits, tested for military functionality and meeting military 

requirements (17 Jul 95). For Galileo will follow on from AOC. 

FOD foreign object debris/damage 

FODCOMS Flight Operations Department Communications (CAA SRG) 

52 

March 2012

FOG fibre-optic gyro (introduced ~ 1985) 

FOM figure of merit 

FOM flying operations manual 

FONA Flag Office Naval Aviation 

FOP Final Operational Phase (of GAGAN - 1 year after IEP) 

FOQA Flight Operations Quality Assurance (US - FDM in Europe) 

Foreshore area between mean high water and mean low water (Springs in Scot) 

FORS fibre-optic rate sensor 

FP Framework Programme (EU) 

6th FP (FP6) 2002-06. 

FPA Flight Procedures Analysis (EGNOS) 

FPBGA fine-pitch ball-grid array (package format of chip, eg GPS rx) 

FPD flat panel display 

FPGA field-programmable gate array 

FPM flicker phase modulation 

FPS flight progress strip (ATC) 

FPU floating point unit (maths co-processor to speed up arithmetic tasks) 

FQIS fuel quantity indicator system (air) 

FQR factory qualification review 

FRA Federal Railroad Administration (US) 

FRAME EC project to encourage implementation of Euro ITS Framework 

Framework 

Directive 

FRC fast rescue craft 

Directive 2002/21/EC of the Euro Parliment and Council of 7 Mar 02 

on a common regulatory framework for electronic comms networks and 

services. 

FRC flight reference card (check-list) 

FREER Free Route Experim'tal Encounter Resolution (EUROCONTROL Prog) 

FREER-3 (1999) investigating delegation of ATC to a’craft via VDL-4. 

FRIN Fellow of the Royal Institute of Navigation 

FRMS fatigue risk management systems (for crews) 

FRP Federal Radionavigation Plan (US) 

Usually produced each even year. 

FRPA fixed radiation/reception pattern antenna 

FRPA-GP FRPA ground plane 

FRS Federal Radionavigation Systems (US) 

FRUIT false replies unsynchronised in time (SSR garbling problem) 

FS fixed service (transmitter) (ITU) 

Fs fractostratus cloud 

FSA Formal Safety Assessment (shipping) 

FSD full-scale development 

FSDPS flight service data processing system 

FSF Flight Safety Foundation (US) 

53 

March 2012

FSINS FOG-based strapdown inerial navigation system 

FSIX Flight Safety Information Exchange (ICAO) 

FSK frequency-shift keying 

FSS fixed satellite services 

FSS frequency-selective surface (for rf selection in nav/com systems) 

FST fuzzy set theory 

FTA fault tree analysis 

FTA Federal Transit Administration (US) 

FTA Freight Transport Association (UK) 

FTD flight training device 

FTE flight technical error 

FTK freight tonne kilometres (measures civil air actual freight traffic) 

FTL Flight Time Limitations (for aircrew - CAP 371 & EU OPS define) 

FTP File Transfer Protocol (Internet) 

FU smoke (met) 

FUA flexible use of airspace 

FVD floating vehicle data (from road vehicle gathering info) 

FWT fixed wireless terminal (eg for WiFi) 

FY Fengyun metsat system (China) 

FZ freezing (met) 

G giga (SI unit multiplier of 10 9 ) 

G-band NATO radar band 4-6 GHz = 7.5-5 cm 

G-STAR GPS Spacial Temporal Anti-jam Receiver 

G/S groundspeed 

G1, G2 GLONASS carrier frequencies/bands 

Frequencies (MHz) are 1,591-1,610 (G1) and 1,240-1,256 (G2). 

G3 (or GPS+) GPS, GLONASS and Galileo 

GA general aviation 

Executive and company aircraft; private and flying club aircraft; 

gliders, sport aviation and airships/balloons; aerial work. 

GA ground antenna 

GAAC General Aviation Awareness Council (UK) 

GAARDIAN GNSS Availability, Accuracy, Reliability anD Integrity Assessment for 

Timing and Navigation. Chronos Technology, U of Bath, GLAs, BT, 

OS, NPL, Imperial Coll London. 

GaAs gallium arsenide 

GACC General Aviation Consultative Committee (CAA) 

GACF Ground Assets Control Facility (Galileo) 

GAD General Aviation Department (CAA SRG) 

GADEROS Galileo Demonstrator for Railway Operation System (ERTMS) 

GAFLEX Galileo Flight Experiment (Germany-Russia industrial team) 

Trial of Galileo signal structure on a GLONASS-M in late 2002. 

54 

March 2012

GAGAN GPS Aided GEO Augmented Navigation (Indian WAAS) 

GAGAN-TDS GAGAN Technology Demonstration System (ISRO and AAI) 

GAGE GPS at Geostationary Transfer Orbit Experiment 

NASA/GPS JPO/DERA project using UK STRV (Oct 2000?). 

GAIN Galileo Industries SA 

Alcatel-Alenia (F) - 19%, Alcatel-Alenia (I) - 19%, Astrium GmbH (G) - 

19%, Astrium Ltd (UK) - 19%, GSS (Sp) - 12%, Thales (F/G/UK) - 12%. 

GAINR GPS-Aided Inertial Navigation Reference System 

GALA GALileo overall Architecture definition (Nov 99 - Dec 00) 

GALEWAT Galileo & EGNOS for Waterway Transport (part of RIS) 

GALILEAN Galileo Application Network (EC) 

To foster the competitiveness of European manufacturers and service 

providers. 

Galilei EC study on interoperability of Galileo with other nav/comms systems 

Galileo European GNSS (GNSS-2) 

Proposed by EU in Feb 99. IOC was to have been 06, now likely to be 

14, with FOC in 20. To inc Open, Safety-of-Life, Commercial, Public 

Regulated (mil) services. 

GalileoSat ESA definition study contract (Nov 99 - Dec 00) 

GALLANT EC project to integrate GNSS for road safety and mobility 

GAMA General Aviation Manufacturers Association (US) 

GAMMA Project to produce an assisted L1 Galileo/GPS/EGNOS rx (GJU) 

GAMTA General Aviation Manufacturers and Traders Association (UK) 

GAN global area network (the ultimate wide area network) 

GAO Government Accountability Office (US) 

GAP Ground Accident Prevention (FSF initiative) 

GAPAN Guild of Air Pilots and Air Navigators 

GARDA Project to develop GPS/Galileo rx (GJU) 

GARMIS Galileo project for support actions (GJU, May 05 - May 07) 

GARNET Galileo Applications and Research Network (EC NoE) 

GAS Government Access Service (of Galileo) 

GASCo General Aviation Safety Council (UK) 

GASG General Aviation Steering Group (CAA) 

GASIL General Aviation Safety Information Leaflet (CAA) 

GASP General Aviation Safety Plan 

GASRWG General Aviation Safety Review Working Group (CAA) 

GAST Galileo Architecture Support Team (Dec 99 - Apr 01) 

GAT general air traffic 

GATCA ATCOs’ union in Greece 

GATCO Guild of Air Traffic Control Officers (UK) 

GATE Galileo Test and Development Environment (Germany) 

GATM Global Air Traffic Management (USAF programme) 

55 

March 2012

GATS Global Automotive Telematics Standard 

Decided by the GATS Forum (23 companies, service-providers and 

universities). GATS 2 (1999) is an open standard for transferring 

traffic info, emergency call, breakdown, dynamic navigation and general 

info using GPS and GSM. Submitted for inclusion in CEN TC 278 

GAUA Galileo adaptive user algorithm 

GAUSS Global AUgmentation for Satellite Systems 

Concept of integratd navigation using core satellite-based and 

augmentation systems eg NELS. 

Gauss-Markov Component used to refine GPS ionospheric delay model 

GAWG General Aviation Working Group (CAA) 

Gb gigabyte (= 1,024 megabytes) 

GB gyro bearing (angular distance from GN to the object) 

GBAS Ground-Based Augmentation System 

GBAS-B Ground-Based Augmentation System Broadcast 

GBCN ground-based communications network 

GBEN ground-based external navigation (system) 

GBT ground-based transmitter 

GC great circle (orthodrome) 

The intersection of a sphere on the earth and a plane through its 

centre. 

GC gyro course 


between gyro north and the fore-and-aft line (of the ship), expressed 

in angular units from gyro north (000º). 

GCA ground-controlled approach 

GCAS ground collision avoidance system 

GCC Galileo Control Centre 

GCI ground-controlled interception 

GCOS Global Climate Observing System 

GCS Ground Control Segment (Galileo) 

GDA GEBCO Digital Atlas 

GDF Geographic Data File 

The European standard used to describe and transfer road networks 

and road-related data for the mapping industry. 

GDGPS Global Differential GPS (US) 

GDOP geometric dilution of precision 

The factor by which the accuracy of a 3-D fix and time are degraded 

by geometrical considerations. 

GE gyro error correction 

Correction of gyro heading error (inc speed error) of a gyro compass. 

Angle between TN and GN, from TN eastwards named E (+), westwards 

named W (-). 

GEBCO General Bathymetric Chart of the Ocean (IHO project) 

56 

March 2012

GEC groundtrack equatorial crossing 

Equatorial angle from the prime meridian to the location that a 

groundtrack intersects the equator when crossing from the southern 

to northern hemisphere. 

GEMINUS Galileo European Multimodal Integrated Navigation User System 

EC study to define Galileo services. Consortium led by Racal. Nov 99 - 

Dec 00. 

GEMS GPS Environment Monitoring System (spectrum analyser for GPS 

GENESIS Galileo Euro Network of Experts to Support the Euro CommISsion 

Nov 99 - Nov 03. 

GEO geosychonous equatorial orbit 

Satellite height of 35,786 km in equatorial plane. 

GEO Group on Earth Observations 

International group formed in 2003 to coordinate other EO groups. 

Geocentric lat Angle at the centre of of the reference ellipsoid between the celestial 

equator and the radius vector to a point on the ellipsoid. 

Geocentric lon Angle between the plane of the geocentric prime meridian and the 

plane of a point’s geocentric meridian. 

Geodesy Science concerned with surveying and mapping the earth's 

surface to determine, e.g., its exact size, shape and gravitational 

field. 

Geodetic accuracy The accuracy of a position with respect to the geodetic coordinates of 

the earth (IMO). 

Geodetic datum A set of parameters specifying the reference coordinate system used 

for geodetic control in the calculation of coordinates of points on the 

earth (ISO). 

Geodetic lat Angular distance between the plane of the geodetic equator and the 

normal to a point on the earth ellipsoid. 

Geodetic lon Angular distance between the plane of the geodetic prime meridian and 

the plane of a point’s geodetic meridian. 

Geographic 

accuracy 

The accuracy of a position with respect to the geographic coordinates 

of the earth (IMO). 

GEOLUT GEostationary Orbit Local User Terminal 

GeoRSS Geospacial Really Simple Syndication (for position-related data) 

GEOSAR geostationary satellites of COSPAS-SARSAT 

GES ground earth station 

GETR Galileo Experimental Test Receiver (for GIOVE satellites) 

GFE government-furnished equipment 

GFS Galvani-Faraday-Sense (of earth's magnetic field) 

GGC Galileo Global Component 

GGS GPS ground station 

GGTO GPS-Galileo Time Offset 

57 

March 2012

GH gyro heading 


defined by the angle between gyro north and the fore-and-aft line (of 

the ship), expressed in angular units from gyro north (000º). 

GHA Greenwich Hour Angle 

GHRSST-PP Global High-Resolution Sea Surface Temperature Pilot Project 

GHS Globally Harmonised System (marine regulations) 

GHz gigahertz (1,000,000,000 cycles per second) 

GI geographic information 

GIA GBAS Interoperability Analysis (EGNOS) 

GIAC GPS Interagency Advisory Council (US) 

GIACC Group on International Aviation and Climate Change (ICAO) 

GIANT Geodetic Infrastructure for Antarctica 

GIANT GNSS Introduction in the AviatioN SecTor (EC proj from Jul 05) 

GIANT GPS Interference and Navigation Tool (US) 

GIC GALILEO Information Centre 

GIC GNSS/Ground Integrity Channel 

GIF Graphics Interchange Format (used on Web) 

GIFTSS Government Information from the Space Sector (UK BNSC) 

GIM global ionosphere map (from IGS) 

GIMOS GNSS Interference Monitoring System 

GINS global inertial navigation system (GPS and inertial) 

GIOVE Galileo In-Orbit Validation Element (GSTBV2A/B) 

GIP Government Industry Partnership (US) (=PPP) 

GIPA Galileo Integrity Performance Assessment 

GIR groundwave-to-interference ratio 

GIRASOLE SoL GPS/EGNOS/Galileo 24 ch rx for air, maritime and rail (GJU) 

GIRT Geospatial Information Response Team (USGS) 

GIS geographical information system 

GISIC Geographical Information Systems International Group 

GISIS Global Integrated Shipping Information System (IMO) 

GISM GPS Scintillation Model/Monitor 

GISMO GNSS Integrity and Signal Monitoring Observatory 

System to monitor and record GPS accuracy and outages. 

GISPE Geographic Information Service Providers in Europe 

GISS Galileo Interim (management) Support Structure 

GITA GPS Interference Testing Approval 

GIVD grid ionospheric vertical delay (eg in WAAS) 

GIVE Geographical Information Vendors Europe 

GIVE grid ionospheric vertical error (eg in WAAS/EGNOS) 

GIWA Global International Waters Assessment 

58 

March 2012

GIWG GPS International Working Group (US, State Dept chair) 

GJU Galileo Joint Undertaking (to become GSA) 

GL Germanischer Lloyd (classification society) 

GLA General Lighthouse Authority (CIL, NLB, TH) 

GLAN geographic longitude of the ascending node (of a satellite orbit) 

Equatorial angle from the prime meridian to the ascending node. 

GLESOC Generic Local Element Service and Operating Centre (GNSS) 

GLF General Lighthouse Fund 

Meets the costs of the GLAs. Derives income mainly from light dues 

charged on commercial shipping calling at UK & Rep of Ireland ports. 

GLNS GPS landing and navigation system 

GLNU GPS landing and navigation unit 

GLONASS GLObal NAvigation Satellite System 

Russian Federation’s GLObal’naya NAvigatsionaya Sputnikova Sistema. 

Equivalent of GPS. Spec is 24 sats in 3 x 64.8º orbital planes at 19,100 

km altitude giving 11 h 15 m orbit time. Operational late 2012? 

GLONASS-K Third generation GLONASS system 

Satellites are smaller and lighter with 10-year operational life. 2005 

-22. 

GLONASS-KM Fourth generation GLONASS system 

Requirement generated in 2002 for deployment 2015-35. 

GLONASS-M Second generation GLONASS system 

Satellites are smaller and lighter with 7-year operational life. First 

launch of 1 sat on 1 Dec 01. Op deployment 2003-13. 

GLORIA GNSS & Loran-C in Road & Rail Applications (EC) 

GLOSS Global Sea Level Observing System 

Research programme coordinated by the IOC. 

GLRT generalised likelihood ratio test 

GLS GPS/GNSS Landing System 

Precision approach equivalent to ILS. Requires 40 m HAL and 12 m 

VAL protection and will be available from LAAS (or WAAS with L5 

frequency available). 

GLS GPS/GNSS Landing Unit 

GLT guided light transit (eg guided bus) 

GM Gauss-Markov (form of Kalman filter) 

GMC ground movement controller (ATC) 

GMDSS Global Maritime Distress & Safety System (see Sea Areas) 

GMES Global Monitoring on Environment and Security (EU/ESA sats) 

GML Geography Mark-up Language 

Format for digital mapping - eg OS MasterMap Address Layer 2. 

GMO Geospatial Management Office (US) 

GMS Ground Mission Segment (Galileo) 

59 

March 2012

GMS Ground Monitor Station (MSAS) 

GMSK gaussian minimum shift keying 

Typically allows 8 kbps to be transmitted over a 12.5 kHz channel. 

GMSP Global Multimission Service Platform (USA) 

Could represent 8 satellites giving both higher-power GPS and comms. 

The 8 could replace the same number of current GPS sats at about the 

time of introduction of GPS III. 

GMT Greenwich Mean Time 

May be regarded as the general equivalent of UT1. 

GMU GPS-based monitoring unit 

US system for checking aircraft navigation performance. 

GN grid north 

Northerly direction indicated by the gyro-compass 000º index. 

gnd ground 

GNE gross navigational error 

GNS Ground Network System (US ATC) 

GNSS Global Navigation Satellite System 

Generic term for satellite navigation systems. GNSS-1 covers GPS and 

GLONASS augmented with additional ranging, differential and 

integrity signals (eg EGNOS, MSAS, WAAS). GNSS-2 should include 

Galileo & Compass. Covered by IMO Res. A.860(20) ‘Maritime Policy 

for the Future GNSS’. 

GNSS/CN Global Navigation Satellite System/Cellular Network 

GNSS/GSM Global Navigation Satellite System/Global System for Mobile Comms 

GNSSP Global Navigation Satellite Systems Panel (ICAO) 

GNST Non-Flight Satellite Testbed (GPS) 

GO geometrical optics 

GOC Galileo Operating Company (concessionaire) 

GOC General Operator’s Certificate (GMDSS) 

GOCE Gravity Filed and Steady State Ocean Circulation Explorer (ESA) 

GODAE Global Ocean Data Assimilation Experiment 

GOERS GPS Outage En Route Simulation (FAA experiment 2002) 

GOES Geostationary Operational Environmental Satellite 

GOES-M carries the SXI. GOES-P is the 16th. 

Gold Code Unique pseudo-random code used by each GPS satellite 

GONG Global Oscillation Network Group (track sunspots) 

GOOS Global Ocean Observing System 

GOTS GPS Outage Terminal Simulation (FAA experiment 2003) 

GOV GNSS-1 Operational Validation (EUROCONTROL) 

GP general purpose 

GP glidepath 

GP&C global position & communication 

GPAT Generic Performance Analysis and Trending (EGNOS) 

60 

March 2012

GPC GIOVE Processing Centre 

Located at ESA’s European Space Research and Technology 

Centre (ESTEC) in Noordwijk, Netherlands. 

GPIAA Gabinete de Prevenção e Investigação de Acidentes com Aeronaves 

Portugese air accident board. 

GPIP glidepath intercept point (of landing aircraft) 

GPMS GPS Perfomance Monitoring System (UK NATS) 

GPNTS GPS-based Positioning, Navigation and Timing Service (USN) 

GPO GPS (Joint) Program Office (US) 

GPRS General Packet Radio Service (GSM-based protocol; ‘2.5G’) 

Mobile phone protocol from 2000 using packet switching at 171.2 kbps. 

GPS Global Positioning System (NAVSTAR) 

Spec is 21 + 3 sats in 6 orbital planes at 55º inclination and 20,200 km 

altitude, giving 12 h orbits. 

GPS III Next generation GPS (first launch 2013?) 

GPS Time Time to which GPS signals are referred 

A composite of all monitor and satellite system clocks, steered over a 

period to keep within 1 microsec of UTC, ignoring UTC leap seconds. 

Equalled UTC in Jan 80; on 1 Jan 06 was ahead of UTC by 14 secs. 

GPS Week Modulo 1,024 number of elapsed GPS weeks 

Began 6 Jan 80 with first roll-over on 22 Aug 99. 

GPS-CV GPS Common View (mode of operating for time transfer) 

GPS/GSM Global Positioning System/Global System for Mobile Communication 

GPS+ (or G3) GPS, GLONASS and Galileo 

GPSDO GPS disciplined oscillator (free runs if GPS unavailable) 

GPSOC GPS Operations Center (USAF - SCHRIEVER AFB) 

GPTS Global Positioning and Timing Service 

GPU graphics processing unit 

GPWC ground proximity warning computer 

GPWS Ground Proximity Warning System 

GR hail >5 mm (met) 

GRACE Generalised Rules for Advanced Constellation Evaluation 

GRACE GNSS Research & Applications Centre of Excellence (Nottingham) 

GRACE Gravity Recovery and Climate Experiment (2 sats - NASA) 

GRADU gradual (met reports) 

GRAIL Galileo introduction in the RAIL sector 

GRAM GPS receiver application module 

GRAPE GPS Routine for Attitude Parameter Estimation 

Software package for processing GPS signals. 

GRAS GPS Receiver for Atmospheric Sounding 

GRAS Ground-based Regional Augmentation System (GPS)(Australia, Russia) 

GRASP Geodetic Reference Antenna in Space 

To enhance GNSS, particularly to measure sea and ice level ht changes. 

61 

March 2012

GRC Geospacial Research Centre (Christchurch, NZ) 

Joint venture between U of Nottingham (UK) and U of Canterbury 

(NZ). Formed Nov 06. 

GREAT Galileo REceiver for the mAss markeT 

2-year, E6 million project under EC FP6. Led by PA Consulting Gp. 

GRI Group Repetition Interval (LORAN-C/eLORAN) 

Integer in range 4,000 to 9,999. Time interval between pulse groups in 

10s of microseconds. 

GRINGO GPS RINEX Generator (IESSG) 

GRM GPS receiver module 

gross error Or ‘outlier’ is error other than random or systematic error. Often 

large and, by definition, unpredictable (After IMO). 

GRP glass reinforced plastic 

GRR ground reference receiver 

GRT gross registered tonnage 

GS glideslope 

GSA European GNSS Agency (took over from GJU) 

GSB Galileo Security Board 

GSC Galileo Security Committee 

GSDI Global Spacial Data Infrastructure 

GSE ground support equipment 

GSI Geographical Survey Institute (Japan) 

GSM Groupe Speciale Mobile or Global System for Mobile 

Digital mobile phone structure also allowing 160-character alphanumeric 

messages (SMS). Uses narrow-band TDMA giving 8 slots per 

frequency at 9.6 kbps. 

GSM-R GSM-Railway (part of ERTMS) 

Secure voice/data comms between drivers & signallers (UK in 2013?). 

GSO geo-synchronous orbit 

GSOS GPS Surface Observing System (US) 

GSPS Global System Performance Specifications (ICAO) 

GSS Galileo Sensor Station 

GSS geospatial server (central server for real-time traffic guidance) 

GSSB Galileo System Security Board 

GSSF Galileo System Simulation Facility (ESA) 

GST Galileo System Time (spec within 50 ns 95%) 

GST Greenwich Siderial Time 

GSTARS Ground Safety Tracking and Reporting System (for airfields) 

GSTB Galileo System Test Bed 

GSTBV2A Galileo System Test Bed Vehicle 2A (GIOVE-A) 

To secure Galileo frequency filing and provide a test SIS. Soyuz 

launched Dec 05. SSTL. 

62 

March 2012

GSTBV2B Galileo System Test Bed Vehicle 2B (GIOVE-B) 

To continue Galileo freq filing and provide a test SIS. EADS Astrium. 

GSVF Galileo Signal Validation Facility 

GSVF Galileo Signal Validation Facility (ESA) 

GT gross tonnage/tons 

GT ground track (intended path of ship’s movement over ground) 

GTO geostationary transfer orbit 

GTP Global Telematics Protocol 

GTP GPS translator processor (of TGRS) 

GTR Group Time Reference (LORAN-C) 

GTRF Galileo Terrestrial Reference Frame (based on ITRF96) 

GTRS Galileo Terrestrial Reference System 

GTS Global Telecommunications System 

GTSP Galileo Time Service Provider 

GUI graphical user interface 

GUST Galileo User Support Transport 

EC project for Galileo receivers. 

GVA gross value added 

GWGGTI GalileoSat WG on the Galileo Time Interface 

GWS GPS wavefront simulator 

h hecto (SI unit multiplier of 10 2 ) 

H henry (inductance in Wb/A) 

H-band NATO radar band 6-8 GHz = 5-3.75 cm 

H-field magnetic-field (eg of aerial) 

H24 continuous round-the-clock operation 

HA harbour authority 

HA Highways Agency (established by UK Government in 1994) 

HA-NDGPS High Accuracy Nationwide DGPS (US) 

HAGR high-gain GPS receiver 

HAL horizontal alert limit/level (eg for WAAS precision approach etc) 

HALE high altitude long endurance (vehicle such as UAV, balloon or airship) 

HAMSR High Altitude MMIC Sounding Radiometer (atmospheric sounder) 

HAP high altitude platform (stratospheric GNSS augmentation platform) 

eg Helios UAV at 20 km altitude. 

HAT height above terrain 

HAZMAT hazardous material 

HAZREP Hazardous Incident Report (shipping) 

HBL hydrostatic balanced loading 

HBP Harvard bi-phase (digital channel) 

HCAA Helenic Civil Aviation Authority 

HCMM The Honourable Company of Master Mariners 

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March 2012

HCRF hydrographic chart raster format 

HCS heading control system 

HD head direction (used in animal navigation) 

HDC Hydrographic Data Centre (UK) 

HDD head-down display 

HDG heading (course) 

Angle measured in horizontal plane from a reference direction, counted 

clockwise from 000º through 360º, written as a 3 digit number. 

HDLC high-level data link control/communication 

HDOP horizontal dilution of precision 

The factor by which a two-dimensional fix in a horizontal plane is 

degraded by geometrical considerations. 

HDX half duplex 

HEA harbour entrance and approach 

HEAP Human Element Analysing Process (IMO) 

HELCOM Helsinki Commission (Baltic Marine Environment Protection Comm) 

To protect marine environment. Denmark, Estonia, EU, Finland, 

Germany, Latvia, Lithuania, Poland, Russia & Sweden. 

HeliNet Proposed network of unmanned solar-powered stratospheric 

Project funded by EC Fifth Framework for environmental surveillance, 

broadband services and positioning. 

HEO highly-elliptical orbit (typically 1,500-40,000 km) 

HEROE Harmonisation of European Rail Rules for Operating ERTMS (EU) 

HEX Horizontal Expansion (programme - eg coverage of 8.33 kHz chnls) 

HF high frequency (3-30 MHz) (decametric waves) 

HF human factors 

HFACS human factors 

HFDL high frequency datalink 

HFM Human Factors andMedicine Panel (NATO RTO) 

Hg Refers to inches of mercury for atmospheric pressure 

ISA 1013.2 mB or hPa = 29.92 ins Hg. 

HGA high gain antenna 

HGE Harmonisation Group on ECDIS 

HGMIO Harmonisation Group on Marine Information Objects (IHO-IEC) 

HGS head-up guidance system 

HGV heavy goods vehicle 

HHP high holding power (anchors) 

HHS Hodgkin-Huxley-Sense (of earth's magnetic field) 

HI High Integrity (Galileo sevice) 

HIAL high intensity approach lighting 

HIDSS helmet integrated display sighting system (for aircrew) 

64 

March 2012

HIPS Highly-Interactive Problem Solver (EUROCONTROL) 

Software for real-time air traffic management. 

HIRF high intensity radio frequency 

HIRL high intensity runway lighting 

HIRLAM High Resolution Limited Area Model (to estimate tropospheric delay) 

HISL high-intensity strobe light 

HITL hardware-in-the-loop 

HL heading line (radar) 

HLD high level definition (document) 

HLG High Level Group 

HLS helicopter landing site 

HMAC Hazardous Materials Advisory Council 

HMD helmet-mounted display 

HMI hazardously misleading information 

HMI human-machine interface/interaction 

HMLR Her Majesty’s Land Registry (UK) 

HMR helicopter main route 

Hmr homer 

HMSD helmet-mounted sight display 

HMU health monitoring unit 

HMU height-monitoring unit 

Ground-based unit for very accurately checking on aircraft height. 

HNS Hazardous and Noxious Substances (IMO Protocol) 

HNSE horizontal navigation system error 

HO height observed 

HO hydrographic office 

HOB Hydrographic Office Board (UK) 

HoE height of eye 

HOL high order language 

HOMER homing marine environmental recorder 

Hon FRIN Honorary Fellow of the Royal Institute of Navigation 

HOT High Occupancy/Toll (eg lanes on motorway) 

HOTAS hands on throttle and stick (ergonomic cockpit technology) 

HOW hand-over word 

HP High Precision (GLONASS military service) 

HP high pressure 

HP holding point 

hPa hectopascal 

Supersedes the millibar. 1mB = 100 pascals = 1 hPa. 

HPA high power amplifier 

HPC high-performance computing 

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March 2012

HPL horizontal protection limit 

HPZ helicopter protected zone 

HR high risk (marine) 

hr hour 

HRA high risk area (marine) 

HRA human reliability analysis 

HRG Hemispherical Resonator Gyro (vibratory gyro for IMU - N Grumman) 

HRS height reference surface 

HRU hydrostatic release unit 

HRV high risk vessel (marine) 

HS high sensitivity (eg GPS receiver) 

HSB hue, saturation, brightness (system of specifying display colours) 

HSC high speed craft 

HSC Homeland Security Council (US) 

HSC Code International Code of Safety for High Speed Craft (IMO) 

HSE Health and Safety Executive (UK) 

HSE health, safety and environmental 

HSEQ health, safety, environment & quality (elements of marine IMS) 

HSGPS high sensitivity GPS 

HSI Homeland Security Institute (US) 

HSI horizontal situation indicator 

HSPDA high speed downlink packet access (mobile phones) 

HSSC Hydrographic Services and Standards Committee (IHO) 

HSWA Health and Safety at Work Act (UK) 

HTML HyperText Mark-up Language (for Web pages) 

HTTP HyperText Transfer Protocol 

HTZ helicopter traffic zone 

HUD head-up display (HUD-LCD uses liquid crystal display) 

HUNE horizontal component of the user navigation error 

HUNGAGI Hungarian Association for Geo-information 

HV host vehicle 

HW hardware 

HW high water 

HX holding to fix 

HZ haze (met) 

Hz Hertz (cycles per second) 

HZA high zenith antenna (eg GPS for elevation >35º) 

I in-phase component 

I-3, I-4 Inmarsat 3rd or 4th generation satellites 

I-4s at 98ºW (Americas), 25ºE (EMEA) & 143.5ºE (Asia-Pacific) 2010. 

Carry navigation package, 200 spot beams and comms up to 432 kbps. 

66 

March 2012

I-band NATO radar band 8-10 GHz = 3.75-3 cm 

I-Level intermediate level 

I-NMF Integrity Network Management Facility (Galileo) 

I&D integrate and dump (correlator function in satnav rx) 

I 2 S 

integrated information system 

IAA International Academy of Astronautics 

IAA Irish Aviation Authority 

IaaS Infrastructure as a Service (cloud computing) 

IAC Information-Analytical Center (Russia - for satnav) 

IACA International Air Carriers Association (of non-scheduled airlines) 

IACS International Association of Classification Societies (London) 

IADC International Association of Dredging Companies 

IAEA International Atomic Energy Agency 

IAF International Astronautical Federation 

Founded in 1951, now has 165 non-governmental corporate members 

from 44 states (2003). Based in Paris. 

IAG International Association of Geodesy 

IAIN International Association of Institutes of Navigation 

Institutes (2007): Australia, Austria, China, Czech Republic, DPR 

Korea, Egypt, France, Germany, Italy, Japan, Korea, Netherlands, 

Nordic, Poland, Portugal, Russia, Spain, Switzerland, UK, US. 

IALA International Association of Lighthouse Authorities 

Comprises some 82 national lighthouse authorities plus associate and 

industrial members. UK represented by Trinity House, Northern 

Lighthouse Board & Irish Lights. Formed 1957. Full title 

‘International Association of Marine Aids to Navigation and Lighthouse 

Authorities’. AISM in French. 

IALPA Irish Air Line Pilots’ Association 

IAMF International Aeronautical Monetary Fund (ICAO) 

Proposal to pay for the implementation of CNS/ATM in poorer 

countries. 

IAN Instituto Argentino de Navegacion 

IAOPA International Aircraft Owners and Pilots Association (55 states 01) 

IAP instrument approach procedure 

IAPH International Association of Ports and Harbours 

IAPP International Air Pollution Prevention Certificate (IMO) 

IAPSO International Association for the Physical Sciences of the Ocean 

IARO International Air Rail Organisation (London registered) 

IAS indicated airspeed 

IASA International Aviation Safety Assessment (FAA programme) 

IASC International Arctic Science Committee 

IASST International Association for Safety and Survival Training 

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March 2012

IATA International Air Transport Association 

IAWP initial approach waypoint 

Based in Montreal. Founded in 1947. Represents some 230 airlines 

comprising 93% of scheduled international air traffic (2010). 

IBAN Internet-Based Augmentation System (a WAAS using www) 

IBC International Bathymetric Chart 

IBC Code International Bulk Carriers’ Code 

Includes equipment in ships carrying dangerous chemicals in bulk. 

IBCS integrated bridge control system 

IBCU inboard computer unit 

IBIS intelligent bus for inertial sensor 

IBIT initiated built-in test 

IBLS Integrity Beacon Landing System (using pseudolite) 

IBn identification beacon 

IBRD International Beacon Registration Database (COSPAS-SARSAT) 

IBS integrated bridge system 

IBW in-building wireless systems 

IC ice crystals (met) 

IC interrogator code (SSR Mode S) 

ICA International Cartographic Association 

ICAA Iceland Civil Aviation Administration 

ICAM Integrated Coastal Area Management 

ICAO International Civil Aviation Organisation (188 nations in 2003) 

ICAO (EUR/NAT) ICAO (European & North Atlantic Region)(ECAC + 11 = 49 states) 

iCAV Integrated Common Analytical Viewer (US - for GPS interference) 

ICB Industry Consultation Body (SESAR) 

ICC integrated control system 

ICC integrity control centre (Galileo) 

ICC International Cartographic Conference (ICA) 

ICC International Certificate of Competence 

ICC International Chamber of Commerce 

ICCL International Council of Cruise Lines 

ICCS Integrated Coastguard Communications System 

ICD interface control document 

ICES International Council for the Exploration of the Sea 

ICeSAT Ice Cloud and land Elevation Satellite 

ICF initial contact frequency (ATC) 

ICF Integrity Control Facility (Galileo) 

ICFTU International Confederation of Free Trade Unions 

68 

March 2012

ICG International Committee on Global Navigation Satellite Systems 

China, India, Italy, Japan, Nigeria, Russia, US, BIPM, CGSIC, 

COSPAR, EUPOS, ESA, FIG, IAG, IAIN, ICA, ICSU, IERS, IGS, 

ISPRS, ITU, URSI, UNOOSA (2008). 

ICHCA International Cargo Handling Co-ordination Association 

ICI inter-carrier interference (comms etc) 

ICMA International Christian Maritime Association 

ICNS integrated communication, navigation and surveillance 

ICOMIA International Council of Marine Industry Associations 

ICS initial control system 

ICS Institute of Chartered Shipbrokers 

ICS International Chamber of Shipping (London-based) 

ICS International Code of Signals 

ICS International Commission on Shipping 

ICSU International Council for Science 

ICT information and communication technology 

UK Government ICT Strategy is prog of shared data centres. 

ICZM Integrated Coastal Zone Management (UK) 

ICZMap Integrated Coastal Zone Mapping (UK OS project 2004-06) 

ID identify, identification, identifier 

IDA Institute for Defense Analysis (US) 

IDDN Integrity Data Dissemination Network (Galileo) 

IDIQ indefinite delivery, indefinite quantity (contract) 

IDM improved data modem 

IDM interference, detection and mitigation (eg GPS) 

IDP information data processing 

IDS integrated display system 

IDS integrity determination system 

IEC International Electrotechnical Commission (est 1906) 

Based in Geneva. Sets standards for electrotechnical devices. 

IEC 61108-1 (1996-06) applies to GPS. Members from 65 

countries, 172 Tech Ctees, 5,000 international stds published. 

IEE Institute of Electrical Engineers (became IET) (UK) 

IEEE Institute of Electrical and Electronic Engineers (US) 

IEG Information Exchange Group (CIL, THLS and NLB) 

IEP Initial Experimental Phase (of GAGAN - 1 year after TDS) 

IERS International Earth Rotation Service 

IES inverted echo sounder 

IESSG Institute of Engineering Surveying and Space Geodesy 

At the University of Nottingham. 

IET Institute of Engineering Technology (was IEE) 

IETF Internet Engineering Task Force 

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March 2012

IETT Institute of European Trade and Technology 

IF inertial frame 

IF initial fix 

IF instrument flying 

IF integrity flag (GNSS) 

IF intermediate frequency 

iFACTS Interim Future Area Control Tools Support (UK NATS) 

Advanced support tools to enable ATC controllers to increase 

amount of traffic they can handle. 

IFALPA International Federation of Airline Pilots’ Associations 

IFATCA International Federation of Air Traffic Controllers' Associations 

Represents ~ 40,000 air traffic controllers in >100 countries. 

IFCS integrated flight control system 

IfEN Institute of Geodesy and Navigation (Univ FAF Munich, Germany) 

IFF Identification Friend or Foe (system) 

IFFAS International Financial Facility for Aviation Safety 

IFFT Inverse Fast Fourier Transform 

IFN Institut Français de Navigation 

IFO intermediate fuel oil 

IFOG interferometric fibre-optic gyro 

IFR instrument flight rules 

IFSMA International Federation of Shipmasters’ Associations (London base) 

IFTA instrument flying training area 

IGA international general aviation 

All international civil aviation ops other than scheduled air services and 

non-scheduled air transport ops for remuneration or hire. 

IGC Code International Gas Carriers’ Code 

Includes equipment in ships carrying liquified gases in bulk. 

IGEB Interagency GPS Executive Board (disestablished) 

Replaced by the National Space-Based Positioning, Navigation 

and Timing (PNT) Executive Committee Aug 05. 

IGEMS Improved GEMS 

IGEX International GLONASS Experiment 

IGN French National Geographic Institute 

IGO inter-governmental organisation 

IGP ionospheric grid point (eg for SBAS) 

IGS Innovation and Growth Strategy (eg Space IGS) 

IGS instrument guidance system 

IGS International GNSS Service 

IGSAGS Integrated Global Surveillance and Guidance System 

IGSO inclined geosynchronous orbit 

Satellite height of ~36,000 km inclined to equatorial plane. 

70 

March 2012

IHB International Hydrographic Bureau 

IHO International Hydrographic Organisation 

Inter-governmental organisation established in 1921. 73 nations in Feb 

01. Based in Monaco. 

IHPT Instituto Hidrográfico (Portugese Navy Hydrographic Institute) 

II Interrogator Identifier (SSR Mode S code) 

IIAR instantaneous integer ambiguity resolution 

IIM Instituto Idrografico della Marina (Italian Hydrographic Office) 

IIMS International Institute of Marine Surveyors 

IIN Italian Institue of Navigation 

IISC International Information Sub-Committee (of CGSIC) 

IISL International Institute of Space Law 

IKD in-kind delivery 

Contribution to a project in-kind rather than by direct funding. 

IKLT Inverse-Karthunen-Loève-Transformation 

ILA International Loran Association 

ILAMA International Life-saving Appliances Manufacturers’ Association 

ILDF Independent Light Dues Forum (UK) 

ILF International Lifeboat Federation 

ILO International Labour Organisation (deals with marine crewing issues) 

ILS Instrument Landing System 

ILS International Launch Services (Russia - use Baikonur Cosmodrome) 

ILT Institute of Logistics and Transport (UK - CILT from May 2004) 

IM integrity monitoring 

IMA integrated modular avionics 

IMarE Institute of Marine Engineers (became IMarEST in 2001) 

IMarEST Institute of Marine Engineering, Science and Technology (was 

IMB International Maritime Bureau 

IMC instrument meteorological conditions 

IMCA International Marine Contractors Association 

IMDG Code International Maritime Dangerous Goods Code (IMO) 

IMEC International Maritime Employers' Committee 

IMERP Implementation of the European Radionavigation Policy 

IMLA integrated multipath-limiting antenna 

IMLA International Maritime Lecturers Association 

IMO International Maritime Organisation 

A UN body formed in 1959 and based in London. 168 members (2008). 

IMP Integrated Maritime Policy (EU) 

IMPA International Maritime Pilots’ Association 

IMPACT ATCOs’ union in Ireland 

IMS Incident Management System 

IMS Integrated Management System (shipping) 

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March 2012

IMS integrity monitor station (eg Galileo) 

IMSO International Mobile Satellite Organisation 

An intergovernmental body to oversee Inmarsat’s delivery of its public 

service obligations, including GMDSS. 

IMT 2000 International Mobile Telecommunications for 2000 and beyond 

An ITU cellphone standard better known as 3G or 3rd Generation. 

IMTA International Map Trade Association 

IMU inertial measurement unit 

IN Information Notice (UK CAA) 

IN-RAR interferometric real aperture radar 

IN-SAR interferometric symthetic aperture radar 

INA International Navigation Association 

iNavSat Consortium bidding for Galileo concession 

EADS Space, Inmarsat & Thales. 

INCOSE International Council on Systems Engineering 

INE Instituto de Navegacion de Espana 

InHg inches of mercury (pressure) 

INITIATIVE EU Project for electronic fee collection using GNSS 

INLS-Code International Noxious Liquid Substances Code 

INLUS Indian Navigation Land Uplink Station (3 for GAGAN) 

INM Internet Notices to Mariners 

Inmarsat INternational MARitime SATellite Organisation 

Established by convention on 3 Sep 76, with 86 member governments 

by 1999. Became a two-tier private company (Inmarsat Holdings and 

Inmarsat Ltd) on 15 Apr 99. 

INMCC Indian Mission Control Centre (3 for GAGAN) 

INPHORMM Info & Pub Helping the Objective of Reducing Motorised Mobility 

INRES Indian Reference Station (15 for GAGAN) 

INS Indian Navigation System (satnav) 

INS inertial navigation system 

INS integrated navigation system 

INSPIRE Infrastructure for Spacial Information in the EU 

A database with consistent geographical data to improve mapping in 

Europe. 

INTEG EGNOS Integration into Galileo 

EC study to analyse a seamless transition from EGNOS to Galileo from 

tech, economical, ops and institutional views. Nov 99 - Dec 00. 

integrated 

navigation system 

A system in which the information from 2 or more navigation aids is 

combined in a symbiotic manner to provide an output which is superior 

to any one of the component aids (IMO). 

integrity The ability to provide users with warnings within a specified time when 

the system should not be usd for navigation (IMO). 

72 

March 2012

integrity risk Probability that a user will experience a position error larger than the 

threshold value without an alarm being raised within specified time-toalarm 

at any instant of time at any location within the coverage area 

(IMO). A typical figure is 10 -7 . 

INTELFRET intelligent freight train 

INTELLECT New name (2002) for FEI - Electronic Industry Trade Organisation 

INTER intermittent or fluctuating (met) 

Intercargo International Association of Dry Cargo Shipowners 

Intercept Intermodal Concepts in European Passenger Transport 

EC DG TREN & DG XIII project. 

Interdecadal Between ten years or in groups of ten 

International 

NAVTEX 

Co-ordinated broadcast and automatic reception on 518 kHz 

‘of marine safety information by means of narrow-band direct-printing 

telegraphy using the English language.’ 

interoperability The ability to communicate or transfer data between functional 

units running on different platforms, implemented in different 

technologies, using industry standard or widely accepted data 

description and communication protocols. 

Intertanko International Association of Independent Tanker Owners 

INWAAS Indian WAAS 

IOC Initial Operational Capability 

For GPS, 24 Block I/II/III satellites operating in assigned orbits and 

available for navigation use. Declared in 1994 for GPS, implying 

suitability for civil use. 

IOC Intergovernmental Oceanographic Commission 

IOD issue of data 

IODC issue of data, clock (GPS) 

IODE issue of data, ephemeris (GPS) 

IOG integrated optics gyro (technology beyond MEMS) 

IOI imminent obstacle impact (TAWS alert) 

IOLT Institue of Logistics and Transport 

IOM input/output module 

ION Institute of Navigation (US) 

ION-CH Swiss Institute of Navigation 

Ionosphere Part of atmosphere from ~ 120-350 km 

IOP Initial Operations Phase (eg EGNOS) 

IOPC International Oil Pollution Compensation Fund 

IOR Indian Ocean Region 

Inmarsat III satellite at 64.5ºE. 

IORS integrated optical rotation sensor 

IOSA IATA Operational Safety Audit 

IOT&E Initial Operational Test & Evaluation 

IOV in-orbit validation 

IP initial point (eg fix before run-in to target) 

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March 2012

IP instrumentation port 

IP Integrated Project (EU FP6) 

IP interlectual property 

IP Internet Protocol 

IPAB International Programme for Antarctic Buoys 

IPAX in-plane accelerometer 

IPC Industrial Policy Committee (ESA) 

IPCC Intergovernmental Panel on Climate Change 

IPF Integrity Processing Facility (eg EGNOS, Galileo) 

IPIN Indoor Positioning and Indoor Navigation (conferences) 

iPLOT Intelligent Pervasive Location and Tracking (Leeds U) 

IPP ionospheric pierce point (for measuring ionospheric delay eg GPS) 

IPPA Innovative Portable Pilot Assistance (marine project) 

IPPS Intelligent Pedestrian Protection System (on cars) 

IPR intellectual property right 

IPTS International Port Traffic Signals 

IPTV Internet Protocol TV 

IPV instrument approach with vertical guidance 

IQ in-phase quadrature 

IR Implementing Rule (EASA) 

IR impulse radio (UWB) 

IR inertial reference 

IR infrared 

IR Instrument Rating 

IRAC Interdepartmental Radio Advisory Committee (US) 

IRAC/SPS IRAC Spectrum Planning Sub-committee (US) 

IRAC/SSG IRAC Space Systems Group (US) 

IRB indoor reference beacon 

IRD interface requirements document 

IRF International Road Federation 

IRI International Reference Ionosphere 

IRIG Inter Range Radio International Group 

Provides continuous worldwide time coverage for navigation, time 

and frequency requirements. 

IRLOGI Irish Organisation for Geographic Information 

IRNSS Indian Regional Navigation Satellite System 

8 satellites operational in 2012? 

IRPCS International Reglations for Preventing Collisions at Sea (1972) 

Also known as COLREGs. 

IRS inertial reference system 

IRT Independent Review Team (USAF) 

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March 2012

IRU inertial reference unit 

IRU International Road Transport Union 

IRVR instrumented runway visual range 

IS information system 

IS intrinsically safe (eg can be used near flamable materials etc) 

ISA Intelligent Speed Adaption (MIRA project 2002) 

ISA International Standard Atmosphere 

In basic terms sea-level pressure of 1013.2mb and temperature of 

+15ºC, with temperature lapse rate of -1.98ºC per 1,000ft to 36,090ft. 

ISAF International Sailing Federation 

ISAGO IATA Safety Audit for Ground Operations 

ISATA International Symposium on Automotive Technology & Automation 

ISDN Integrated Services Digital Network 

ISF International Shipping Federation Ltd (London-based) 

ISGOTT International Safety Guide for Oil Tankers and Terminals 

ISI inter-symbol interference (comms etc) 

ISIS integrated standby instrument system 

ISL inter-satellite link 

ISM Industrial, Scientific and Medical (freq band, typically ~2.4 GHz) 

ISM International Safety Management (Code)(IMO) 

Code for safe operation of ships and for polution prevention. 

ISMA International Ship Managers' Association 

ISMASS Ice Sheet Mass Balance and Sea Level 

ISMS In-flight Safety Monitoring System (data transmission fm aircraft) 

ISO independent system operator 

ISO International Organisation for Standardisation (est 1946) 

Members from 157 countries, 190 Tech Ctees, 15,000 

international standards published. Based Geneva. 

ISO International Security Organisation 

isochrone Contour of equal travelling time from a point (for routeing software) 

ISOL isolated (met) 

Isostatic In hydrostatic equilibrium from equality of pressure 

ISOTOPE Improved Structure & Organisation for Trans Ops of Pax in Europe 

ISP internet service provider 

ISPP International Sewage Pollution Prevention Certificate (IMO) 

ISPRS International Society of Photogrammetry and Remaote Sensing 

ISPS International Ship and Port Security Code 

ISR intelligence, surveillance and reconnaissance 

ISRO Indian Space Research Organisation 

ISS integrated sensor suite 

ISSA International Shipsuppliers & Services Association 

ISSN international standard serial number 

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March 2012

IST Information Society Technologies (EC) 

IST integrated satellite test 

ISTB International Satellite Test Bed (EU initiative) 

ISU International Salvage Union 

ISWG Intersessional Working Group (IMO) 

IT information technology 

ITAS Integrated Topographic Analysis System (to predict GPS Jamming) 

ITC International Trade Commission (US) 

iTEC-eFDP interoperability Through European Collaboration – european 

Flight Data Processing 

ITF International Transport (Workers) Federation 

ITI imminent terrain impact (TAWS alert) 

ITIS Integrated Transport Information Services (travel inf for logistics) 

ITM Institue of Transport Management 

ITN Integrated Transport Network (data layer of OSMM) 

Comprises Roads Network and Road Routing Information (RRI). 

ITOFAR Interrogated Time Offset Frequency Agile Racon 

ITRF IERS Terrestrial Reference Frame (currently ITRF2000) 

ITS Intelligent Transport Society 

ITS intelligent transport(ation) system 

The application of IT and comms to all surface transport modes. 

ITS intermediate level test set 

ITSF International Telecom Sync Forum 

ITSUK Intelligent Transport Society for the UK ( >130 members) 

ITU Intermodal Transport Unit (EU container for any form of transport) 

ITU International Telecommunication Union 

ITU-R is Radiocommunication Sector (ex-CCIR) and ITU-T is 

Telephony and Telegraphy (ex-CCITT). ITU is a UN Agency. 

ITWS Integrated Terminal Weather System (gives ATC 20-min wx)(US) 

ITZ Inshore Traffic Zone 

IUGG International Union of Geodesy and Geophysics 

IUGS International Union of Geological Sciences 

IULS Integrity Uplink Station (Galileo) 

IUSM International Union for Surveys and Mapping 

IVHS intelligent vehicle highway system 

IVI Intelligent Vehicle Initiative (US) 

IVIS in-vehicle information system 

IVMS Integrated Vessel Management System 

IVR interactive voice response (phones/computers) 

IVS in-vehicle system 

IVSI instantaneous vertical speed indicator (air) 

IVTF International Volcanic Ash Task Force (IVTF) 

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March 2012

IVU in-vehicle unit 

IWAAS Initial WAAS 

Capable of supporting navigation and CAT I precision approach but 

lacking internal redundancy and guaranteed availability. 

IWAN internal wide area network 

IWP intermediate waypoint 

IWV integrated water vapour 

J-band NATO radar band 10-20 GHz = 3-1.5 cm 

J/S jamming-to-signal ratio 

JAA Joint Aviation Authorities (40 members in 2006) 

JANE Joint Air Navigation Experiments (EU) 

JANSC Joint Air Navigation Services Council (MOD/NATS) 

JAR Joint Aviation Requirement (of the JAA) 

JAR-OPS Joint Aviation Requirement Operations Manuals 

JARUS Joint Authorities for Rulemaking on Unmanned Systems (EU) 

JAXA Japanese Aerospace Exploration Agency 

JCAB Japanese Civil Aviation Bureau 

JCG Joint Coordinating Group 

Comprising chairmen & chief executives of the GLAs. 

JCMACC Joint Civil Military Airspace Coordination Committee (EU SES) 

JD Julian Day (count of days from midday on 1 January 4713 BC) 

JDRMA Japan Digital Road Map Association 

JERICHO Impact of a Changing Wave Climate on our Coasts (BNSC project) 

JGPSC Japan GPS Council 

JIBS Joint Irish Bathymetric Survey (Project under INTERREG IIIA) 

JIN Japan Institute of Navigation 

JLOC Jammer Detection and Location System (US for GPS) 

JMC Joint Maritime Commission (of ILO) 

JMSA Japan Maritime Safety Agency 

JNRP Joint Navigation Requirements Policy (GLAs) 

JOI Joint Operating Instruction 

JOS Joint Operation Schedule (EGNOS) 

JPALS Joint Precision Approach and Landing System 

Rapidly-deployable military system. Was extended (2003) to use LAAS 

to get to CAT III. Joint US Forces. 

JPEG Joint Photographic Expert Group 

Standard for digital image compression. 

JPL Joint Propulsion Laboratory (Pasadena CA, USA) 

JPO Joint Program Office (US) 

JRANS Japan Regional Air Navigation System (planned for much of S Asia) 

JRC Joint Research Centre (EC) 

JRCC joint rescue co-ordination centre 

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March 2012

JRSC joint rescue secondary centre 

JSC Joint Spectrum Centre (US) 

JSR jamming-to-signal ratio 

JSR Java Specification Request 

An optional package that enables developers to write mobile 

location-based applications for resource-limited devices. 

JTC Joint Tripartite Committee (EGNOS) 

JTIDS Joint Tactical Information Distribution System (US/NATO DL) 

Also known as NATO Link 16. 

JTSO Joint Technical Standard Order (JAA) 

JU Joint Undertaking (Galileo management) 

JUCG Joint User Consultative Group on Aids to Navigation 

Set up in 1988 by the then Dept of Transport. Now run by the GLAs 

with secretariat at TH. 

JWG Joint Working Group (ICAO and IMO) 

k kilo (SI unit multiplier of 10 3 ) 

K-band NATO radar band 20-40 GHz = 1.5-0.75 cm 

K-band Old radar band 18-27 GHz (ITU assigned 24.05-24.25 GHz) ~ 1.5 cm 

K a -band Old radar band 27-40 GHz (ITU assigned 33.4-36.0 GHz) ~ 1 cm 

Kalman Filtering Mathematical method of combining data to give optimal position 

(velcity etc) solutions whilst on the move. 

KAREN European ITS framework architecture 

kbit kilobit 

1,024 bits or 128 8-bit bytes. 

kbps kilobits per second 

KCP Crew Knowledge and Proficiency (marine) 

KF Kalman filter 

kg kilogram (1,000 grams) 

kHz kilohertz (1,000 cycles per second) 

KIAS knots indicated airspeed 

KIN Korean Institute of Navigation 

KinPos GPS/INS integration software package (Nottingham University, UK) 

Klobuchar model to calculate slant ionospheric delay (eg GPS) 

KLT Karthunen-Loève-Transformation 

km kilometre (1,000 metres) 

KMF key management facility 

kn knot (unit of velocity and speed) 

1 kn = 1 NM/h = 0.514444 m/s. 

KNAG Royal Dutch Geographical Society 

KPI key performance indicator 

KR Korean Register of Shipping (classification society) 

KSI killed or seriously injured (accident stats) 

78 

March 2012

kt knot 

KTA key technical advisor 

KTN Knowledge Transfer Network (eg Location and Timing) 

KTP Knowledge Transfer Partnership 

Scheme to bring in tech expert to help devel product or business. 

K u -band Old radar band 12-18 GHz ~ 2 cm 

(ITU assigned 13.4-14.0 & 15.7-17.7 GHz) 

kVA kilo volt-amps 

kW kilowatt (1,000 watts = 1.341 horsepower) 

L-band NATO radar band 40-60 GHz = 7.5-5 mm 

L-band Old radar band 1-2 GHz (ITU assigned 1,215-1,400 MHz) = 30-15 cm 

L/L latitude and longitude 

L1, L2, L5 GPS carrier frequencies (in the old L-band) 

Frequencies (MHz) are 1,575.42 (L1), 1,227.60 (L2) & 1,176.45 (L5). 

L2C second civil signal (GPS - carries CNAV) 

L2CCO Level 2 Certificate in Coaching Orienteering 

LA Local Authority 

LAADR Low-Altitude Arrival/Departure Route 

LAAS Local Area Augmentation System (GPS etc) 

Operational date in USA 2004. 

LAC Lights Advisory Committee (GLAs) 

LAC location area code (phone network) 

LAD 

linear averaging digital (Loran technique from Locus Inc) 

LADGNSS Local Area Differential GNSS 

LADGPS Local Area Differential GPS 

LAHSO land and hold short operation (to expand runway capacity) 

LAL lateral alert limit/level (eg for WAAS precision approach etc) 

LAL LBS Application Level 

LAMBDA least-squares ambiguity decorrelation adjustment (algorithm) 

LAN local apparent noon 

LAN local area network 

LAN longitude of the ascending node 

The point where an orbit intersects the equator when crossing from 

south to north. 

LANBY Large Automatic Navigation Buoy 

LARS Lower Airspace Radar Service 

LAS local area system 

LAS lower airspace service 

laser light amplification by stimulated emission of radiation 

LASOIS Lunar Astronaut Spatial Orientation and Information System 

LAST Light Aviation SSR Transponder (Mode S proposed for UK) 

79 

March 2012

Lat (LAT) (j) latitude (angular distance from equator, labelled N or S) 

May be geographic, geodetic, geocentric or astronomical. 

LAT local apparent time 

LAT lowest astronomical tide 

LATCC London Area and Terminal Control Centre (ATC) 

LATN Low Altitude Tactical Navigation (USAF) 

LATS London Area Traffic Survey (UK DTLR) 

LAVIA Limiteur s’Adaptant à la Vitesse Autorisée (French EVSC) 

LB lighted buoy 

LBA Luftfahrt Bundesamt (German CAA) 

LBMON L-Band Monitor (computer program) 

LBS lifeboat station 

LBS location-based service(s) 

LBSN location based social network 

LBSP location-based services provider 

LC liquid crystal 

LCA liquid crystal transmissive array 

LCC Low Cost Carrier (airline) 

LCCC leadless ceramic chip carrier 

LCD liquid crystal display 

LCLA Local Cave Leader Award 

LCN low-cost navigator 

LCoS liquid crystal on silicon 

LDA landing distance available 

LDGPS Local Differential GPS (or LADGPS) 

LDT light displacement tonnage 

LDTL low-density traffic line (railway) 

LDW lane departure warning (ADAS feature) 

LE local element 

LEA location enabled technology 

LED light-emitting diode 

leeway angle Angular difference between course through water and course to steer. 

Leg intended ground track between 2 waypoints 

LEO low earth orbit 

Satellite orbit of up to 3,000 km. 

LEOLUT low earth orbit local user terminal 

LEOSAR low earth orbit stellites of COSPAS-SARSAT 

LEP linear error probable 

Half of the interval containing half of the results of the trials in a 

series of one-dimensional measurements. 

LES land earth station (same as CES operationally) 

LESO land earth station operators 

80 

March 2012

LETFEL leteral emitting thin film electroluminescent device (for displays) 

LEUT local element user terminal (GNSS) 

LEX Unique experimental signal from the Michibiki QZSS (Japan) 

LF light float 

LF low frequency (30-300 kHz) 

LFA low/local flying area 

LFC Lighthouse Finance Committee (GLAs) 

LFC low flying chart 

LFS low flying system 

LFSR linear feedback shift register 

LFV Luftfartsverket (Swedish CAA) 

LGA land grid array (type of chip) 

LGF LAAS ground facility 

LH lighthouse 

LHA local hour angle 

LHCP left hand circularly polarised 

LHS left hand seat (cockpit) 

LIBERAIL Liberalised and Interoperable Railways (EU) 

LICTA ATCOs’ union in Italy 

LIDAR Laser Induced Direction and Range (airborne scanning sys for DEMs) 

LIFSZ ATCOs’ union in Hungary 

Light aircraft aircraft with a max takeoff weight of 12,500 lbs (5,700 kg) or less 

LIM local integrity monitor 

LINCS Low-cost Identification, Navigation, Communication, Surveillance 

LINK2000+ Critical step in data-link tech & applications (precursor to SESAR) 

LINS laser inertial navigation system 

LIP limited installation program(me) 

LISA limited instruction set architecture 

LISP Local Integrated Service Package (Galileo) 

LITAS low-intensity two-colour approach system 

LJAO London Joint Area Organisation (ATC) 

LKLY likely (met) 

LLA local lighthouse authority 

LLI loss of lock index 

LLN laser linescan navigation 

LLPG local land and property gazetteer 

lm lumen (luminus flux in cd sr) 

Lm Mean latitude (half the sum of the latitudes of 2 places) 

LMDS local-multipoint distribution service 

81 

March 2012

LMES land mobile earth station 

LMM locator middle marker (ILS) 

LMSE least mean square error 

LMT local mean time 

The arc of the celestial equator between the lower branch of the local 

celestial meridian and the hour circle of the true sun. 

LMU location measurement unit 

LMU location monitoring unit (to synch ‘time’ in a cellular system for nav) 

LNA low noise amplifier 

LNAV lateral navigation 

An initial WAAS service to give non-precision approach down to 400 

-500ft. No vertical guidance. Requires 556 m HAL protection. 

LNAV/VNAV lateral and vertical navigation 

An initial WAAS service to give precision approach down to 350ft and 

1 n mile. May also be referred to as non-precision approach with 

vertical guidance. Requires 40 m HAL and 12 m VAL protection. 

LNB low-noise block (antenna component) 

LNM Local Notice to Mariners 

LNV land navigation vehicle (for testing airborne systems - USAF) 

LO local oscillator 

LOA length overall 

LOA letter of agreement 

LOC localiser (azimuth guidance portion of ILS) 

LOCOG London Organising Committee of the Olympic Games 

LOCOLOC LOw-COst LOCcalisation (for train integrity (ESA)) 

LOCOPROL (or just LOCO) 

LOw-COst satellite-based train location system for signalling and train 

PROtection for Low density traffic railway lines. EC FP 5, 2001-04. 

Locus Pinpoint project on location contect tools for 3G services 

City University & The Geoinformation Group. 

LOGIC Loran GNSS interoperability channel 

LOIS Land Ocean Interaction Study 

LOM locator outer marker (ILS) 

Lon (LON) (l) longitude 

Angle at the pole between prime meridian and meridian of a point, 

labelled E or W. May be geographic, geodetic, geocentric or 

astronomical. 

LOP line of position (also PL) 

LOPAS London Olympics and Paralympics Airspace Steering Group (CAA) 

LOR legal and organisational review (EC) 

LOR Long-term Operations & Replenishment (phase of Galileo fm 2008) 

LORADD eLoran receiver (Reelektronika) 

82 

March 2012

LORAN LOng RAnge Navigation 

LORAN-C is a terrestrial pulsed hyperbolic system in band 90-110kHz. 

LORAPP Loran Accuracy Panel (US FAA) 

LOREG Loran/Eurofix/EGNOS (Norwegian test and evaluation plan) 

LORIPP Loran Integrity Panel (US FAA) 

LORSTA Loran station 

LOS line-of-sight 

Loxodrome rhumb line 

LPM Loran Propagation Model (software package) 

LPST Low Power SSR Transponder 

LPV Lateral Precision with Vertical Guidance (landing system) 

Uses GPS/WAAS. Requires 40 m HAL and 50 m VAL protection. 

LR long range 

LRC Long Range Certificate (for GMDSS MF/HF equipment) 

LRIP low rate initial production 

LRIT long range identification and tracking (of ships) 

LRK long-range kinematic (of GPS) 

LRM line-replaceable module 

LRNS long range navigation system 

LROPS long-range operations 

LRP LORAN-C Recapitalization Project (US - $120 million) 

LRU line-replaceable unit 

LRUC Lorry Road User Charge (UK programme of HM Customs & Excise) 

LS leap seconds (=TAI - UTC; was +32s Nov 00) 

LS least square 

LSB least significant bit 

LSF leap seconds future 

LSI large scale integration (of chips) 

LSR least squares residual 

LSU Loran Support Unit (USCG) 

LSVA Swiss Heavy Vehicle Free Area 

LT local time 

LTE Long Term Evolution (next-generation mobile broadband technology) 

LTF Legal Task Force (EUROCONTROL) 

LTMA London Terminal Manoeuvring Area (ATC) 

LTP LAAS Test Prototype (US) 

LTP local transport plan 

LUCH Russian geo sats (5) providing comms & GLONASS diff corrections. 

Also known as ‘Altair’. 

LUT local user terminal (COSPAS-SARSAT) 

LV light vessel 

83 

March 2012

LVTO low visibility take-off 

LW low water 

lx lux (illuminance in lm/m 2 ) 

lyµ micro (SI unit multiplier of 10 -6 ) 

lyµ-FORS micro-fibre-optic rate sensor 

lyµ-XANES microscopic X-ray absorption near-edge structure 

lyµ-XRF microscopic X-ray fluorescence 

lyµT micro Tesla (earth’s magnetic field is earth is ~50) 

lzµ Earth’s gravitational constant (typically 3,99 x 10 14 m 3 /s 2 ) 

lzµV/m microvolts per metre 

m metre 

m milli (SI unit multiplier of 10 -3 ) 

M-ADS Modified Automatic Dependent Surveillance 

Mandatory for helicopters in Norwegian Sector of North Sea from 

Apr 99. 

M-band NATO radar band > 60 GHz = < 5 mm 

M-Code Military Code for GPS (military signal - spec produced in 2000) 

Due to be used with last 12 Block IIR satellites and Block IIFs on L1 

and L2 

M-GEX Global Multi-GNSS Experiment (IGS) 

M-Notice Merchant Shipping Notice (UK) 

M-Spot (Mspot/M Spot) Mil GPS way of focussing sig to give higher power 

m/s metres per second 

M&A Mach 

M&A magnetic 

M&A mega (SI unit multiplier of 10 6 ) 

M&A nautical mile on charts under IHO Spec of 1982 

Approx 1,852 m or 6,080 ft. 

M&C monitor and control station 

M&S models and simulation 

M&T measurement & testing 

M2M machine-to-machine (comms) 

MA map aiding 

MAC medium access control 

MAC miniature atomic clock 

Mach No (M) Ratio of TAS to local speed of sound 

MAFF Ministry of Agriculture, Fisheries and Food (UK - now DEFRA) 

mag magnetic 

Mag magnitude (of star) 

MAGES Mature Applications of Galileo for Emergency Scenarios (GSA) 

MAGR Miniaturised Airborne GPS Receiver (US - Rockwell) 

MAGVAR magnetic variation 

84 

March 2012

MAIA Measuring Atlantic Inflow into the Arctic (EU MAST V project) 

MAIB Marine Accident Investigation Branch (UK) 

MaLoC Management Location Content (position- & time-stamped for LBS) 

MAP missed approach point 

MARAD Maritime Administration (US) 

MARE (MERR) maximum allowable range error 

MAREP Mariner Reporting System 

MARIS Maritime Information Society (EC DG III - formed May 97) 

www.maris.int 

MARPOL Int Convention for the Prevention of Pollution from Ships (1973/78) 

MARSOURCE A fisheries & marine environment info network (MARIS) 

MARTRANS Info network on movement of cargo vessels (MARIS) 

MARUSE GJU maritime project under FP6 (Oct 05 - Oct 70) 

To promote the use of Galileo and EGNOS. 

maser microwave amplification by stimulated emission of radiation 

MASPS Minimum Aircraft Systems Performance Specification 

ICAO standards required of aircraft wishing to use areas of reduced 

separation standards, eg MASPS (altimetry) required for RVSM. 

MAST Marine Science and Technology (EC R&D project - MAST III 

MasterMap OS definitive map database of UK 

MAT monitoring and analysis tool 

MATCA ATCOs’ union in Malta 

MATHP missed approach holding waypoint 

MATO military air traffic operations 

MATRIX Proprietary form of E-OTD that can self-determine precise time 

MATS Manual of Air Traffic Services (UK - CAP 493) 

MATWP missed approach turning waypoint 

MATZ Military Air Traffic Zone 

Usually 5 n miles radius up to 3,000 ft with stubs of 2,000-3,000 ft to 

10 n miles aligned with main runway. 

MAU modular avionics unit 

MAUW maximum all-up weight 

MAV micro aerial vehicle 

MAWP missed approach waypoint 

Mayday “m’aidez" - help me. International radio distress call 

MB magnetic bearing (angular distance from MN to the object) 

MB marker beacon 

Mb megabyte (= 1,048,576 bytes) 

mb millibar (deprecated - replaced by mbar) 

Superseded by the hectopascal (hPa). 1mbar = 100 pascals = 1 hPa. 

MBB Maritime Black Box (EU R&D project) 

MBOC multiplexed binary offset carrier (used by Galileo) 

85 

March 2012

Mbps Million bits per second 

MC magnetic course 


between the magnetic meridian through its position and the fore-andaft 

line (of the ship), expressed in angular units from magnetic north 

(000º). 

MC main computer 

MC master clock 

MC-UWB multi-carrier UWB 

MCA Marine and Coastguard Agency 

An executive agency of the UK DfT, based in Southampton. 

MCA mobile communication services on aircraft 

MCB multi-communications box 

MCBF mean cycles between failures 

MCC Master Control Centre (EGNOS - Toulouse) 

MCC Mission Control Centre (COSPAS-SARSAT) 

MCC mobile country code (phone network) 

MCC multi-crew cooperation 

MCDU multifunction control and display unit 

MCF Mission Control Facility (Galileo) 

MCM multi-chip module (several chips in one package) 

MCMT mean corrective maintenance time 

MCPA Marine and Coastal Protected Area 

Mcps megachips per second 

MCS Master Control Station (GPS - Colorado Springs) (MSAS) 

MCS Mission Control System (Galileo) 

MCT mercury cadmium telluride (IR sensor material) 

MCTA military control area (ATC) 

MCTZ military control zone (ATC) 

MCW modulated continuous-wave 

MCWG Maps and Charts Working Group (CAA) 

MDA minimum decision altitude (of landing aircraft) 

MDA Mobile Data Association (UK) 

MDB marginally detectable bias 

The minimum size of the gross error in an observation that may be 

detected with given probability. Gross error detection may apply to 

wrongly rejecting an observation without a gross error (type 1) or 

wrongly accepting an observation with a gross error (type 2). 

MDCE Maritime Data Centre of Europe (independent, based in Copenhagen) 

MDE marginally detectable error 

The maximum position offset caused by a MDB in a LOP or observation. 

MDE minimum detectable error 

86 

March 2012

MDES Measurement Data recording and data Evaluation System (DFS) 

German system for permanent GNSS data recording, monitoring and 

analysis. 

MDGPS Maritime DGPS (USCG, part of NDGPS) 

MDH minimum descent height (of landing aircraft) 

MDIS Midlands Driver Information System 

MDM modem data manager 

MDO marine diesel oil 

MDT mean down time 

MDT mobile data terminal (in vehicle) 

MEA minimum enroute altitude (US) 

Meaconing Receiving and re-broadcasting nav signals to confuse nav receivers 

MECP Mobile Electronics Certified Professional (UK) 

MED Marine Equipment Directive 

MEDA military emergency diversion aerodrome 

MEDEVAC medical evacuation 

MEDLL multipath estimating delay lock loop (eg in GPS receiver) 

MEGRIN Multi-purpose Ground Related Information Network (mapping 

MEHRA marine environmental high risk area 

MEL minimum equipment list (eg to operate an aircraft safely) 

May be associated with DDG/CDL). 

MELTT French Ministry of Transport 

MEMS micro-electromechanical system (eg micro IMU from ~ 1995) 

MENTORE iMplemENtation of GNSS tracking & tracing Technologies fOR Eu 

regulated domains 

MEO medium earth orbit 

Satellite orbits of 3,000-30,000 km. 

MEOLUT medium earth orbit local user terminal (eg Galileo) 

MEPC Marine Environment Protection Committee (IMO) 

MERC maritime emergency reception centre 

For dealing with ships in difficulty rather than distress. 

Merged 

Consortium 

For Galileo Concession (bid in Oct 05) 

AENA, Alcatel, EADS Space, Hispasat, Inmarsat, Finmeccanica, 

Thales. 

Meridian Great circle through the geographical poles of the earth 

Meridional 

difference 

(DF) Difference of the meridional parts of any 2 given parallels 

Merparts (F) Meridional parts 

Length of the arc of a meridian between the equator and a given 

parallel on a Mercator chart, expressed in units of 1’ of longitude on 

the equator. 

MERPR maximum allowable error in pseudorange 

MERR (MARE) maximum allowable range error 

87 

March 2012

MERSAR MERchant ship Search And Rescue (IMO manual) 

MERV maximum tolerable vertical position error 

MES mobile earth station 

For maritime use known as SES. For land use known as LES or LMES. 

MESA maximum entropy spectral analysis 

MESA Mobility for Emergency & Safety 

A single platform for a range of applications related to TETRA bu on 

3.8-4.9 GHz. 

MESF Mobile Electronics & Security Federation (UK) 

MESFET metal semiconductor field effect transistor 

Mesosphere Part of atmosphere from ~ 50-85 km 

METAR meteorological aerodrome report 

METAREA sea area for GMDSS meteorological infomation 

MetFAX UK Met Office faxed-based dial-up weather service 

Metop Satellites (3) forming EPS 

MF medium frequency (300-3,000 kHz) (hectometric waves) 

MFA major floating aid (light vessel, LANBY, light float) 

MFC multi-frequency channel 

MFD multi-function display 

MFDS multi-function display system 

MGA Multi-GNSS Asia (Japan) 

MGF Message Generation Facility (Galileo) 

MGM-net The MGA/JAXA multi-GNSS monitor network (Japan) 

MGN Marine Guidance Notice (MCA) 

MGO marine gas oil 

MGUE Modernized/Military GPS User Equipment (US programme) 

MH magnetic heading 


defined by the angle between the magnetic meridian through its 

position and the fore-and-aft line (of the ship), expressed in angular 

units from magnetic north (000º). 

MHRS magnetic heading reference system 

MHW mean high water 

MHWN mean high water neaps 

MHWS mean high water springs 

MHz megahertz (1,000,000 cycles per second) 

MI misleading information 

MI shallow (met) 

MIC mounain instructor certificate 

MICA multiyear interactive computer almanac 

Micro-PNT Micro-Technology for Positioning, Navigation and Timing (DARPA) 

microcell As a femtocell, but range increased to ~2 km 

88 

March 2012

microwaves radio waves > 1 GHz 

MID maritime identification digits 

MIDAR Marine Identity Data Automatic Response (similar to aviation SSR) 

MIDAS Motorway Incident Detection and Signalling System 

MIDAS Multi-Instrument Data Analysis System (math model for ionos delay) 

MIDS Multifunction Information Distribution System (data link) 

MiFi Mobile WiFi (3G router giving WiFi in local area up to ~10m) 

MIL-STD Military Standard 

MILSPEC Military Specification 

MIME Multipurpose Internet Mail Extension 

MIN Marine Information Note (UK) 

min minimum 

min minute 

MINT Micro Inertial Navigation Technology (DARPA project) 

MIO marine information object (time-variable object in ECDIS) 

MIOC multifunction integrated optic chip (used in fibre-optic gyros) 

MIP Multiannual Indicative Programme (EC DG TREN) 

MIPS million instructions per second 

MIRA Motor Industry Research Association 

MIRG Maritime Incident Response Group (UK) 

MIS management information system 

MIS Marine Information System (ECDIS may contribute to it) 

MISNA Marine Information Service of North America 

MISTER Minimum Interoperability Spec for Tolling on European Roads 

MIT Massachusetts Institute of Technology (US) 

MITRA Monitoring and Intervention for the TRAnsportation of Dangerous 

Goods (EC FP6 - 2004-06). 

MJD Modified Julian Day (started midnight 17 November 1858) 

Equals JD - 2,400,000.5. 

MKD minimum keyboard display (eg AIS) 

mkr marker/marker beacon (on 75 MHz for ILS) 

MLA Mountain Leader Award 

MLA multipath-limiting antenna 

MLC Mountain Leader Certificate 

MLE maximum likelihood estimator 

MLLW mean lower low water 

MLP multi-layer perceptron (neural network) 

MLS Microwave Landing System 

MLS mobile laser scanning 

MLU mid-life update 

MLV medium launch vehicle 

89 

March 2012

MLWN mean low water neaps 

MLWS mean low water springs 

MM map-matching 

MM MasterMap (Ordnance Survey trademark) 

MmaxCT maximum corrective maintenance time 

MMC multi-media card (typical 64 Mb) 

MMD mean mission duration 

MMD moving map display 

MMG micro-mechanical gyro (a form of MEMS) 

MMI man-machine interface (nowadays replaced by 'HMI') 

MMIC microwave monolithic integrated circuit 

MMLE method of maximum likelyhood estimation (adaptive filter technique) 

MMLS Mobile Microwave Landing System 

MMR multi-mode receiver 

MMS Multimedia messaging service (mobile phones) 

MMSI Maritime Mobile Service Identity (Code) (GMDSS DSC) 

MMW millimeter-wave (eg radar) 

MMW multipath mitigation window 

MN magnetic north 

Northerly direction of the horizontal component of the earth’s 

magnetic field. 

MNC mobile network code (phone network) 

MNE Marine Navigation Equipment (Sub-Group of UK SON Ctee) 

MNM mathematical navigation monitor 

Provides position estimate with associated errors by data fusion of 

dissimilar sensors. 

MNP Master Navigation Plan (US) 

MOA memorandum of agreement 

MOB man overboard 

MoBIC Mobility of Blind and Elderly People Interacting with Computers 

MoC memorandum of cooperation 

MOCA minimum obstruction clearance altitude (US) 

MOD Ministry of Defence 

Mode SSR mode of operation 

Mode A - normal ATC codes, Mode C - encoded flight levels, Mode S - 

selective interrogation and downlinking of aircraft parameters (DAPs). 

Mode S Mode Select - SSR using selective addressing 

Selection based on ICAO 24-bit unique address for each aircraft. 

Also allows downlinking of flightplan callsign and altitude in 25 ft 

increments. Includes ELS and EHS. Mandatory in Europe for IFR 

flights from 31 Mar 05. 

modem modulator-demodulator 

MOEMS micro-opto-electromechanical system (eg micro IMU) 

90 

March 2012

mogas car fuel 

MOIE Mission-Oriented Investigation and Experimentation (FAA projects) 

MOMENTUM Mobility Management for the Urban Environmnt (EU) 

MOMO Navigation tool for blind pedestrians using mobile phone (ESA proj) 

MON Minimum Operational Network (FAA - of VORs by 2014) 

MoODS MoBIC Outdoor System 

MOPS Minimum Operational Performance Standards 

A set of standards defining minimum performance, functions and 

features for RNAV and, optionally, VNAV equipment. 

MOR Mandatory Occurrence Reporting scheme (CAA) 

MORANE Mobile Radio for Railway Networks in Europe (EU RTD project) 

MOSAIC Mobility Strategy Applications in the Community (EU) 

MOST Media Orientated System Transport (protocol for mobile internet) 

MOU memorandum of understanding 

MOVA Microprocessor Optimised Vehicle Actuated (traffic signal prog) 

MOVE (DG MOVE) Directorate General Mobility & Transport (EC ex-TREN) 

MP meridian passage 

MPA maritime patrol aircraft 

MPCU Marine Pollution Control Unit (UK) 

MPD Mandatory Permit Directive (CAA) 

MPEG Motion Picture Experts Group 

Standard for digital audio compression (eg MP3). 

MPERS Mobile Personal Emergency Response System (US) 

MPF Mission Planning Facility (Galileo) 

MPFA multi-position fusion algorithm 

MPLS multi-protocol label switching (networks) 

MPNTP Master Positioning, Navigation and Timing Plan (US) 

MPS Mobile Positioning Systems (=VPS)(generic term used by DTLR) 

MPT European radio regulation prefix to be replaced by ETS 

MQM measurement quality monitoring 

MR medium risk (marine) 

MR mixed reality 

Technologies which use both hardware tracking technologies (i.e. 

GPS, digital compass) and software (AR, VR, mobile interfaces). 

MRAC Marine Radio Advisory Committee (MCA) 

MRCC Maritime Rescue Co-ordination Centre 

MRCC multiple receiver consistency check 

MRD mission requirement document 

MRIN Member of the Royal Institute of Navigation 

MRIT Maritime Radar Interrogator-Transponder (system) 

MRLG monolithic RLG (3 orthogonal RLGs in one block, eg Kearfott T-10) 

MRO maintenance, repair and overhaul 

91 

March 2012

MRS Monitor and Ranging Station (MSAS) 

MRS multi-constellation regional system 

MRSA mandatory radar service area (military ATC) 

MRSC Maritime Rescue Secondary (Sub) Centre 

MRSE mean radial spherical error 

MRT mountain rescue team 

MRTD machine-readable travel document 

MRV Monitoring, Reporting and Verification (EU ETS) 

MRVA minimum radar vectoring altitude 

ms millisecond (one-thousandth of a second) 

MS Monitor Station (eg GPS) 

MSA Marine Safety Agency 

Was part of DETR, replaced in Apr 98 by MCA. 

MSA minimum safe altitude 

MSA minimum sector altitude 

MSAs Merchant Shipping Acts (in UK empower the GLAs) 

MSAS Multi-transport Satellite-based Augmentation System 

Japanese WAAS. 

MSAWS minimun safe altitude warning system 

MSB most significant bit 

MSB multi-sensor box 

MSC Maritime Safety Committee (IMO) 

MSD minimum separation distance 

MSDP multi-sensor data processor 

MSF Callsign of UK 60 kHz time & freq TX used by radio-cont clocks. 

MSF Mission Support Facility (Galileo) 

MSFD Marine Strategy Framework Directive (EU) 

MSG Meteosat Second Generation (3 met/S&R sats first launched 2002) 

MSI Maritime Safety Information (IMO) 

MSK minimum shift keying 

msl mean sea level 

MSN Merchant Shipping Notice (M-Notice)(UK) 

MSP Modes S Specific Protocol 

MSS mean sea surface 

MSS mobile satellite service 

MSSR monopulse secondary surveillance radar 

MSSS Modes S Specific Services 

MSU mobile satcom unit 

MT mobile terminal 

MT mobile terminated (call or SMS to a mobile device) 

MTA military training area 

92 

March 2012

MTB Mediterranian Test Bed (part of STENAV for Galileo) 

MTBCF mean time between critical failures 

MTBDE mean time between downing events 

MTBF mean time between failures 

The average time between 2 successive failures of a system or part of 

a system. 

MTBM mean time between maintenance 

MTCD Medium-Term Conflict Detection (System) (used in ATC centres) 

MTG Meteosat Third Generation (ESA met sat 2010+) 

MTIE maximum time interval error 

MTJ magnetic tunnel junctions (used eg in magnetometers) 

MTOM maximum take-off mass 

MTOW maximum take-off weight 

MTRA military temporary reserved airspace 

MTSA Marine Transporation Security Act (US 2002 - mandates LRIT) 

MTSAT (MT-SAT) Multi-function Transport Satellite 

Japanese (JCAB) geostationary satellite carrying met, comms, nav 

overlay and ATC surveillance functions. First launch (of 2) failed. 

MTT minimum time track 

MTTF mean time to failure 

MTTR mean time to repair/restore 

MUAC Maastricht Upper Area Control Centre (EUROCONTROL) 

MUE modernised user equipment (eg GPS) 

Multilateration Surveillance technique to determine position of an aircraft on basis of 

measurement of the Time Difference of Arrival (TDoA) of a 1,090 

MHz signal transmitted by aircraft from at least 3 locations. 

multistack Simultaneous use of 2 or more datalinks, eg VDL Mode 4 and FANS 

-1/A. 

MUSIK EC 5th FP project for multi-source/applications in positioning 

MUSSST Multimodal Safety Satellite System for Transport 

EC study to establish principles for safety approval of use of GNSS. 

MUX multiplexer 

mV/m millivolts per metre 

MVBA micro-machined vibrating beam accelerometer (for MEMS IMU) 

MVBM Micromachined Vibrating Beam Multisensor (IMU - Kearfott) 

MVEDR motor vehicle event data recorder (black-box - IEEE 1616a is std) 

MVUE manpack/vehicular user equipment 

MVUE minimum variance unbiassed estimator 

MWO Met Watch Office (for en-route hazardous wx warnings to aircraft) 

MWS multmedia wireless systems 

Telecommunications and broadcasting via the same radio network. 

MYRTLE Multi-Year Return Tidal Level Equipment 

n 

93 

March 2012

N newton (force in m kg s --2 ) 

n mile nautical mile (sometimes NM, M on charts) 

Approx 1,852 m or 6,080 ft. 

N/A not applicable 

N/I non-instrument (of aircraft approach) 

Na nadir (point on the celestial sphere vertically below the observer) 

NAA National Aviation Authorities 

NACOS navigation and command system (marine) 

NAD North American Datum 

NADC National Antarctic Data Centre 

NADICS NAtional Driver Information and Control System (Scottish Office) 

NAGU Notice Advisories to GLONASS Users 

NANU Notice Advisory to Navstar Users 

NAO North Atlantic Oscillation 

NaPTAN National Public Transport Access Nodes (UK) 

Database of bus, coach and tram stops, bus and train stations, taxi 

ranks and ferry and air terminals. 

NARSIA North American Remote Sensing Industries Association 

NAS National Academy of Sciences (US) 

NAS National Airspace System (US) 

NAS Naval Air Station (US) 

NAS Newly Associated States (into the EU) 

NAS IG National Airspace System Implementation Group (Australia) 

NASA National Aeronautics and Space Administration (US) 

NASDA National Space Development Agency of Japan 

NAT North Atlantic 

NATCA National Air Traffic Controllers Association (US) 

National Grid Metric transverse Mercator grid based on OSGB36 (OS) 

NATMAC National Air Traffic Management Advisory Committee (UK) 

NATO North Atlantic Treaty Organisation (26 states) 

Belgium, Bulgaria, Canada, Czech Republic, Denmark, Estonia, France, 

Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, 

Luxembourg, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, 

Slovenia, Spain, Turkey, UK, US (2007). 

NATS National Air Traffic Services Ltd (UK ATSP) 

NATSPG North Atlantic Systems Planning Group 

NAUPLIOS Navigation and Perilous Goods Input and Ouput System (Galileo proj) 

NAV IMO Sub-Committee on Safety of Navigation (NAV 49 sits in 2003) 

NAV-msg Navigation Message 

A 37,500-bit data message included in the GPS signal, sent at 50 bps. 

Includes satellite ephemeris, clock data, almanac etc. 

Navaid NAVigation AID 

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March 2012

NAVAREA Sea area for GMDSS radio navigation warnings 

NAVCEN Navigation Centre (USCG) 

NAVD North American Vertical Datum 

Naviair Danish air navigation service provider 

navigation The process of planning, recording and controlling the movement of a 

craft from one place to another (IMO). 

NAVSOL navigation solution 

NAVSTAR NAVigation Satellites with Timing And Ranging (GPS) 

NAVTEX Navigational Information Telex Services 

NavWar NAVigation WARfare (includes military GPS programme) 

NAWC Naval Air Warfare Centre (USN - Patuxent River) 

NBDP narrow band direct printing (eg GMDSS and NAVTEX) 

NCAA Norwegian Civil Aviation Administration 

NCAGS Naval Cooperation and Guidance for Shipping (NATO) 

NCAP (Euro) New Car Assessment Programme (Brussels-based) 

NCF National Coaching Foundation (trading arm is scUK) 

NCF Navigation Control Facility (Galileo) 

NCI National Coastwatch Institution (UK) 

NCP National Contact Point (eg for FP6) 

NCP National Contingency Plan 

NCR negative climb rate (TAWS alert) 

NCS Network Co-ordinating Station (Inmarsat) 

NCS network communication system 

NCW network centric warfare 

NCW non-coherent continuous wave (transmission) 

ND navigation display 

NDB nondirectional beacon 

NDC National Document Centre (Greek AGI) 

NDGPS Nationwide DGPS (US) 

NDPB non-departmental public body (UK) 

NE normalised error (for GNSS compares with HDOP = 4) 

NEAN North European ADS-B Network (EU/EUROCONTROL) 

NEAP North-European ADS-B Application Project (EU) 

NEC network-enabled capability 

NECSA Navigational Electronic Chart System Association 

NELS Northwest European LORAN-C System 

NEMO Navigation system analysis suite for European Maritime Operations 

GLAs/Nottingham Scientific (UK). 

NEMS nano-electromechanical system (technology beyond MEMS) 

NEOSIT navigation/electro-optic sensor integration 

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March 2012

Nepheloid layer Body of water with a high concentration of suspended sediment 

found near the deep ocean floor, close to the base of a 

continental slope. 

NeQuick model to calculate slant ionospheric delay (eg Galileo) 

NERC Natural Environment Research Council (UK) 

NERC New En Route Centre (Swanwick, UK) 

NERL NATS (En-Route) Plc 

NES Navigation Ground Earth Station (MSAS) 

NESTA National Endowment for Science, Technology and the Arts (UK) 

NESTBed North European Satellite Test Bed (experimental SBAS) 

NEXCOM Next Generation Air/Ground Communications (US) 

Digital air/ground comms system (generic name of VDL-2 follow-on) 

NEXGEN next generation ATC system (US FAA - similar to EU’s SESAR) 

NF null field 

NFC near field communication 

NFM near field monitor 

NFZ no-fly zone 

NG National Grid (UK) 

NGA National Geospatial-Intelligence Agency (USA) 

NGATS Next Generation Air Transport System (US) 

NGD Naval Guarantee Department (Chinese HO) 

NGDC National Geophysical Data Centre 

NGDF National Geospacial Data Framework (UK) 

NGIA National Geospatial Intelligence Agency (US) 

NGO non-governmental organisation 

NGPS Natural GPS (ie unaided) 

NGS National Geodetic Survey (US) 

NGVD National Geodetic Vertical Datum (US) 

NHC Nordic Hydrographic Commission (of IHO) 

NHS Norwegian Hydrographic Service 

NHTSA National Highway Traffic Safety Administration (US) 

NI The Nautical Institute 

NIB non-interference basis 

NICT National Inst of Information & Communications Technology (Japan) 

NIKITA Netherlands TMC service 

NILU Norsk institutt for luftforskning (Norwegian Inst for Air Research) 

NIMA National Imagery and Mapping Agency (US)(ex-DMA) 

NIMSA National Interest Mapping Services Agreement (UK Gov and OS) 

NIN Netherlands Institute of Navigation 

NIS Navigation Information Service/System 

NISC National IFF/SSR Committee 

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NITS National ITS (Association) 

NK (NKK) Nippon Kaiji Kyokai (classification society) 

NKTF Norwegian Ass for Cartography, Geodesy, Hydro’ & Photogrammetry 

NLB Northern Lighthouse Board (Commissioners of Northern Lighthouses) 

Covers Scotland and the Isle of Man. 

NLCCS New Loran Consolidated Control System (USCG) 

NLES Navigation Land Earth Station (eg EGNOS) 

NLPG National Land and Property Gazetteer (UK local governments) 

NLR Netherlands National Aerospace Laboratory 

NLS National Land Survey of Sweden 

nm nanometre (10 -9 m) 

NM nautical mile (not universally used but better than 'nm') (also M) 

Approx 1,852 m or 6,080 ft. 

NM Notice to Mariners 

NMA navigation message authentication (eg for secure VHF data link) 

NMA Norwegian Mapping Authority 

NMCA National Mapping and Cadastral Agency 

NMEA National Marine Electronics Association (US) 

Has set standard message formats for transferring GPS data. NMEA 

-0183 is the usual one. 

NMI National Metrological Institute (NPL is the UK NMI) 

NMRI National Mayday Readiness Initiative (US) 

NN neural network 

NNAS National Navigation Award Scheme (UK) 

NNF Nordisk Navigasjonsforum 

Nordic Institute of Navigation. Åland Islands, Denmark, Faeroe 

Islands, Finland, Greenland, Iceland, Norway. 

NNR national nature reserve 

NNSS Navy Navigation Satellite System (Transit) 

NOA Notice of Arrival (US requirement - 96 hrs for ships >300 GT) 

NOAA National Oceanic and Atmospheric Administration (US) 

NOC National Oceanography Centre (Southampton) 

NODC National Oceeanographic Data Centre (US) 

NoE Network of Excellence (EU) 

NOF Navigation on Foot (RIN SIG) 

NOF NOTAM Office 

NOIA National Ocean Industries Association (US ~270 member companies) 

nomadic mobile devices which may be carried from vehicle to vehicle 

NOMADS North Sea Model Advection Dispersion Study (EU MAST project) 

NON unmodulated continuous-wave emission 

Non-precision 

Approach 

A standard instrument approach procedure in which only horizontal 

guidance is given. 

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NONAV no navigation (ATC call/squawk in event of loss of nav capability) 

NOR notice of readiness (shipping) 

NORDO no radio (ATC squawk) 

NOS National Ocean Service (US) 

NOSC Naval Ocean Systems Center (US) 

NOSIG no significant change (met) 

NOTAM Notice to Airmen 

NP Naval Publication 

NP non-periodic 

NPA non-precision approach 

A standard instrument approach in which no electronic glidepath/slope 

is provided. 

NPA Notice of Proposed Amendment (EU JAA) 

NPEF National PNT Systems Engineering Forum (US) 

NPL National Physical Laboratory (The UK NMI)) 

NPPL National Private Pilot’s Licence 

(A) = aircraft, (B) = balloons, (H) = helicopters, A(M) = microlights. 

NPR noise preferential route (ATC) 

NPRM Notice of Proposed Rulemaking (FAA, FCC etc) 

NPTG National Public Transport Gazetteer (UK) 

NPV net present value 

NPV non-precision approach with vertical guidance 

NRC Navigation Research Centre (NUAA) 

NRL Naval Research Laboratory (US) 

NRNP Norwegian Radionavigation Plan (first edition issued 2003) 

NRP National Route Program (US ATC) 

NRS Navigation-Related Communication Services (GALILEO) 

NRT near real-time 

NRT net registered tonnage 

NRTK Network Real-Time Kinematic 

NRTS National Roads Telecommunications Services 

ns nanosecond (1/1,000,000,000 of a second) 

NS Naval Station (US) 

Ns nimbostratus cloud 

NSA National Security Agency (US) 

NSA National Supervisory Authority 

NSA CC National Supervisory Authority Coordination Committee (EU SES) 

NSAP Network Service Access Point (ATN) 

NSC National Security Council (US) 

NSC NATO Shipping Centre 

NSC no significant cloud 

NSC non-standard C/A code (GPS) (for verification etc) 

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NSCC Navigation System Control Centre (Galileo) 

NSE navigation system error 

NSGU Navigation Signal Generation Unit (Galileo) 

NSIDC National Snow and Ice Data Centre (US) 

NSL NATS Services Ltd 

NSO National Solar Observatory (Tucson, USA) 

NSP navigation signal processor 

NSRS National Spatial Reference System (US) 

NSTB National Satellite Test Bed (WAAS) 

NSW no significant weather 

NT net tonnage 

NT new technology 

NTD National Topographic Database (UK) 

NTDS Navy Tactical Data System (US) 

NTE not-to-exceed 

NTF National Transfer Format (OS format to transfer digital mapping) 

NTIA National Telecommunications & Information Administration (US) 

NTM (NtM) Notice To Mariners 

NTP network time/timing protocol (eg NTPv4 in 2008) 

NTS National Travel Survey (UK DTLR) 

NTS Navigation Technology Satellite 

NTSB National Transportation Safety Board (US) 

NTSC National Television Standard Committee (US/Japan TV standard) 

NTSC National Transportation Systems Center (US) 

NUAA Nanjingl University of Aeronautics & Astronautics (China) 

NUC not under command 

NUMAST National Union of Marine, Aviation & Shipping Transp't Officers UK 

NUP NEAN Update Programme (EUROCONTROL) 

NUP north pole up (of a magnet) 

NVC National Vocational Qualification (UK) 

NVEE night vision enhancement equipment 

NVG night vision goggles 

NW navigational warning (marine) 

NWP numerical weather prediction 

NWS National Weather Service (US) 

º degree (unit of angle = /180 rad 

O/B on board 

O/H overhead 

O&M operations and maintenance 

O&S operations and support 

OAB operational advisory broadcast 

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March 2012

OAC Oceanic Area Control 

OAC Operations Advisory Committee (CAA) 

OACC Oceanic Area Control Centre 

OANS onboard airport navigation system 

OAS Open Access Service (Galileo basic service, free of charge) 

OASIS Operational and Supportability Implementation System (FAA) 

OAT operational air traffic 

OAT outside air temperature 

OBDS onboard diagnostic system 

OBE on-board equipment 

OBI omni-bearing indicator 

OBIA object-based image analysis 

OBO ore/bulk/oil (carrier)(ship) 

OBS omni-bearing selector 

OBT on-board terminal 

OBU on-board unit (in a vehicle) 

OCA obstacle clearance altitude 

OCA Oceanic Control Area 

OCC Operations Control Centre (Inmarsat) 

OCG Operations Coordination Group (EUROCONTROL) 

OCH obstacle clearance height (for landing aircraft) 

OCIMF Oil Companies International Marine Forum 

OCR optical character recognition 

OCS operational control system 

OCS outer continental shelf 

OCX Advanced Control Segment (GPS update from 2010) 

Includes anti-jam, improved security, accuracy and reliability. 

ODA Olympic Delivery Authority (UK for 2012) 

ODAS Ocean Data Acquisition System 

ODBC open database connectivity (allows databases to exchange data) 

ODBMS Object Database Management System 

ODL opposite direction level (ATC) 

ODN Ordnance Datum Newlyn (UK system for orthometric height amsl) 

ODR Operations Definition Review (EGNOS) 

ODR output data rate 

ODTS (OD&TS) Orbit Determination and Time Synchronisation (Galileo sys) 

OECD Organisation for Economic Cooperation and Development 

2004 - Australia, Austria, Belgium, Canada, Czech Republic, 

Denmark, Finland, France, Germany, Greece, Hungary, Iceland, 

Ireland, Italy, Japan, South Korea, Luxembourg, Mexico, 

Netherlands, New Zealand, Norway, Poland, Portugal, Slovakia, 

Spain, Sweden, Switzerland, Turkey, UK and US. 

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OEM original equipment manufacturer 

OEP object-orientated engineering process 

OEP Operational Evolution Plan (US FAA) 

OES (USA) Bureau of Oceans & International Environmental & Scientific Affairs 

Ofcom Office of Communications 

Took responsibility of UK spectrum management from RA in Dec 03. 

OFDM orthogonal frequency division multiplex 

OFP operational flight program 

OFT Office of Fair Trading (UK) 

Oftel Office of Telecommunications (UK) (Transfer to Ofcom 29 Dec 03) 

OGC Open Geospacial Consortium (int industry consortium, 417 companies) 

OGDI Open Geospacial Datastore Interface 

OHI Organisation hydrographique internationale (IHO) 

OIG Office of the Inspector General (US DOT) 

OJTI on-the-job training instructor 

okta one-eigth (of cloud cover) 

OLED organic light-emitting display 

OM operations manual 

OM outer marker (ILS) 

OM&S Operation, Maintenance and Support (US) 

OMA Open Mobile Alliance (for mobile phones) 

Formed in 2002 by ~200 companies. 

OMBO one man bridge operation 

OMEGA Optimal Method for Estimating GPS Ambiguities (RTK software) 

Omega VLF navigation system now out of service (withdrawn 30 Sep 97) 

OMEX Ocean Margin Exchange (EU MAST project) 

OMUX output multiplexer 

ONR Office of Naval Research (USN) 

ONS Office for National Statistics (UK - independent fm 1 Apr 08) 

OnStar 2nd generation in-vehicle nav system (GPS + GSM) (General Motors) 

OOD officer of the deck 

OOK on-off keying 

OOP object-orientated paradigm 

OOSA Office for Outer Space Affairs (UN, based in Vienna) 

OOW officer of the watch 

OPA 90 Oil Polution Act 1990 (USA) 

OPE Operational Elements (EGNOS) 

OpenGIS Open Geodata Interoperability Specification 

Being developed by the Open Geospatial Consortium Inc. 

OpEval operational evaluation 

OPF Operations Preparation Facility (Galileo) 

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March 2012

OPG out-of-plane gyroscope 

OPMET Operational Met Information (METAR, TAF, SIGMET etc) 

OPRC 90 Oil Pollution Preparedness, Response and Cooperation (Convention) 

Adopted by IMO ‘90, came into force ‘95. 66 states ratified by ‘02. 

OPRC-HNS IMO Protocol to expand OPRC 90. Adopted 2000. 

OPRG optical passive ring-resonator gyro 

OPSCON operations concept 

OPTXS Optical Transport & Synchronization Commitee (ATIS) 

OPUS Online Positioning User Service (NOAA for GPS) 

OQR Operations Qualification Review (EGNOS) 

ORD observed range deviation 

Observed range difference at a GPS Monitor Station between 

measured sat's position and the sat's position broadcast in Nav Data. 

ORD operational requirement document 

OREGIN ORganisation of European GNSS and service INdustries 

Group of 45 companies to provide public authorities with access to 

technical and marketing espertise. Led by FDC (France). Formed in 

2000. 

ORIENTA System for visually impared in cities (Spain) 

ORR operational readiness review 

Orthodrome great circle 

OS Open Service (Galileo) 

Providing position (5-10m) and time (50ns) free of charge, but no 

integrity info. 

OS Ordnance Survey (UK) 

OSA own speed across track 

OSAPR Ordnance Survey ADDRESS-POINT reference 

OSC Office of Space Commercialization (US) 

OSCAR Ordnace Survey digital dataset for mapping UK 

OSGB Ordnance Survey GB (OSGB-36 datum hitherto used on OS charts) 

OSGi Open Service Gateway Initiative (telematics standard) 

OSGM91 Ordnance Survey Geoid Model 1991 (UK) 

OSI Open System Interconnection (defined by ISO 7-layer model) 

OSI Ordnance Survey of Ireland 

OSL own speed along track 

OSM Office of Spectrum Management (US) 

OSM Openstreetmap Foundation 

OSMA One Scotland Mapping Agreement (with OS) 

OSMM Ordnance Survey MasterMap (UK) 

OSNI Ordnance Survey of Northern Ireland 

OSPAR Oslo and Paris Commission 

European body co-ordinating national decisions on maritime 

environment issues. 

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OSPF Orbitography and Synchronisation Processing Facility (Galileo) 

OSS Orbitography and Synchronisation Station (Galileo) 

OSTN97 Ordnance Survey National Grid Transformation 1997 (UK) 

Used to convert from ETRS89 to OSGB36 and ODN. 

OSV offshore support vessel 

OT&E Operational Test and Evaluation 

OTA operational technical accuracy 

Accuracy with which craft is controlled as measured by indicated craft 

position with respect to indicated command or desired position. Does 

not include blunder errors. 

OTDOA observed time difference of arrival (cellphone location technique) 

OTF on-the-fly 

OTF Open Telematics Framework 

OTF optimum traffic frequency (best comms freq to use - normally in HF) 

OTMR on-train recording and monitoring system 

OTS Organised Track Structure (N Atlantic) 

OTT over-the-top (Internet vid/audio without service provider involved) 

OVC overcast (8 oktas of cloud) 

OVN Osterreichischer Verein für Navigation 

Austrian Institute of Navigation 

OWC obstacle warning and cueing 

OWPA objects without a postal address (UK) 

OWS OGC Web Services (OWS-2 is Phase 2 Initiative) 

OZT obstacle zone by target 

p pico (SI unit multiplier of 10 -12 ) 

P positioning 

P-Code (or P(Y)) Precision (or Pseudorandom) Code 

A PRN code transmitted by GPS satellites. Comprises 2.35 x 10 14 chips 

sent at 10.23 Mbps, which would take 266 days to send. Each satellite 

is assigned a unique one-week segment of the code, which is reset each 

Sat/Sun midnight. 

P-CPICH Primary Common Pilot Channel (GNSS downlink) 

P-RNAV precision area navigation 

ICAO definition - having a nav performance equal to or better than a 

track-keeping accuracy of ±1 NM 95% of time. 

P(Y) encrypted P-Code (comprises modulo-2 addition of P-Code & W-Code) 

P/F platform (of satellite, eg Galileo) 

P/L payload (of satellite, eg Galileo) 

P&I (P and I) Protection and Indemnity (Club) 

P2P pass-to-pass (eg of accuracy) 

P2P peer-to-peer (eg in ITS) 

P3I pre-planned product improvement 

P4 pseudorange and phase post-processor 

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March 2012

Pa pascal (pressure in N/m 2 ) 

PA position approximate 

PA precision approach 

PaaS Platform as a Service (cloud computing) 

PAC pulse aperture correlator (eg of GPS receiver) 

PACF Performance Assessment & Checkout Facility (EGNOS) 

Located at Toulouse. 

PACT Pilot Action for Combined Transport (EU) 

Programme to give financial support for innovative combined transport 

schemes. 

PAD packet assembly/disassembly device 

PAD predicted area of danger (ARPA etc) 

PADS Position and Attitude Determination System 

PAF Postcode Address File (Royal Mail, 25.2 million in England and Wales) 

PAL Phase Alternating Line (European TV standard) 

Uses 25Hz frame rate of 720x576 pixels. 

PAM Precision Approach Module (GNSS landing system) 

PAMR Public Access Mobile Radio 

Pan international radio call signalling ‘urgency’ 

PAN personal area network (eg Bluetooth) 

PAN position and navigation 

Panamax Market category of ships notionally within the limit for transit of the 

Panama Canal. 

PANDORA Prototyping a Navigation Database of Road-Network Attributes 

PANORAMA Personalised Applications based on Reliable Positioning, Communication 

and GIS Management Systems in Alpine Regions (Germany). 

PANS Procedures for Air Navigation Services (ICAO) 

PANSA Polish Air Navigation Services Agency 

PAPA Parallax Aircraft Parking Aid 

PAPI precision approach path indicator 

PAR precision approach radar 

Parallel of altitude Circle on the celestial sphere parallel to the celestial horizon, 

connecting all points of equal altitude. Also called circle of equal 

altitudes. 

Parallel of latitude Circle on the earth’s surface parallel to the equator 

PARAMOUNT Public Safety & Commercial Info Mobility Applications in the 

Mountains. EC project started in 2002. 

Paris MOU Paris Memorandum of Understanding on Port State Control 

Information on all ships that are inspected is held centrally in an 

electronic database known as SIReNaC 

PAS Publicly Available Specification (IEC) 

PATH Program(me) on Advanced Technology for the Highway 

Patriot Watch System to real-time monitori, locate & notify GPS interference (US) 

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March 2012

pax passengers 

PaxCar RoRo ferry for longer routes with cars, treated as a passenger vessel 

PAYD pay-as-you-drive 

PB-NAV Programme Board on Satellite Navigation (ESA) 

PBN performance-based navigation 

Navigation system, largely based on satellite navigation, whereby 

aircraft can navigate point-to-point. 

PC personal computer 

PC phase code (eg LORAN) 

PCA possible course of action 

PCD preferred compass direction (used in animal navigation work) 

PCI phase code interval (LORAN-C)(20 times the GRI) 

PCM phase change memory 

PCM pulse code modulation 

PCMCIA Personal Computer Memory Card International Association 

PCS personal communication services (eg cellphone) 

PD public domain 

PDA personal digital assistant (electronic handheld information device) 

PDA premature descent alert (TAWS) 

PDC personal digital communicator 

PDC pre-departure clearance (ATC) 

PDC Public Data Corporation (UK Government, launched Jan 11) 

PDD Presidential Decision Directive (US) 

PDD NSTC-6 (28 Mar 96) applied to GPS. Included provision of SPS 

free of user charges. Replaced by PNT Policy Directive Dec 2004. 

PDF Portable Document Format 

Standard for making electronic documents portable. Usually created 

on Adobe Acrobat Writer and read by Adobe Acrobat Reader. 

PDF probability density function 

PDL pseudolite 

PDO process data object 

PDOP positional dilution of precision 

The factor by which the accuracy of a 3-D fix is degraded by 

geometrical considerations. 

PDR preliminary design review 

PDSS Pilot Decision Support System (maritime) 

PDT Peripheral Detection Task (to measure objective workload) 

PE-90 A Russian terrestrial reference frame (diff from WGS 84 by 1-2 m) 

PEC Pan European Conference (IFALPA) 

PED personal electronic device 

PEGASUS Prototype EGNOS Analysis System Using SAPPHIRE (EUROCONT’L) 

Pelagic of, performed on or belonging to the upper layers of the open sea 

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March 2012

PENS Pan European Network Services (ATM IP based network service) 

PER packet error rate (comms) 

PETAL Preliminary EUROCONTROL Test of Air/Ground Data Link (prog) 

PETAL II completed in 2002. 

PEU portable external unit (part of PPU) 

PF primary factor (cause of Loran signal delay - also SF and ASF) 

PFA Popular Flying Association 

Pfa probability of false alarm (eg in RAIM) 

PFC primary flight computer 

PFD personal floatation device 

PFD position-fixing device 

PFD power flux density 

PFD primary flight display/director 

PFD/ND primary flight display/navigation display 

PFI Private Finance Initiative (UK type of PPP) 

PFJS Portable Field Jamming System (GPS - US) 

PFL practice forced landing 

PFM prototype flight model 

PGA pin grid array (IC package with one face covered with pins in a grid) 

PGCAS Predictive Ground Collision Avoidance System 

PHARE Prog for Harmonised Air Traf’c Manage’t & Res’ch in EUROCONTROL 

PHM passive hydrogen maser 

PHMI probability of hazardously misleading information 

PHYD pay-how-you-drive 

PI practice interception 

PI pre-planned product improvement 

PI presentation interface 

PIANC (AIPCN) Permanent International Ass'n of Navigation Congresses 

Also known as International Navigation Association. Brussels based. 

PIARC World Road Association 

PIC pilot in command 

picocell As a femtocell, but range increased to ~200 m 

PIDS prime item development specification (EGNOS) 

PIGA pendulous integrating gyro assembly 

PIM Passenger Information Monitor 

PINS Pipeline Inspection Notification System (ATC) 

PIR portable ILS receiver 

PIRT Purposeful Interference Response Team (GPS - US) 

PIS Passenger Information System (rail) 

PIT passive integrated transponder (ident tag, often under animal’s skin) 

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March 2012

pixel picture element 

The smallest element of a computer display or output that can be 

controlled. 

PK pseudo-kinematic 

PKI Public Key Infrastructure (for encrypting/decrypting messages) 

PL ice pellets (met) 

PL position line (also LOP) 

PL pseudolite 

Platooning Auomatic close separation between cars (to increase road occupancy) 

= eConvoy or eTow-bar. 

PLB personal locator beacon 

PLC planar lightwave circuit (eg for connecting FOGs etc) 

PLD programmable logic device 

PLEDM phase-state low electron drive memory 

PLF passenger load factor (% of civil air available seat kilometers used) 

PLGR Precision Lightweight GPS Receiver (US) 

PLL phase-locked loop 

PLOC prolonged loss of cantact (air comms) 

PLSS Precision Location Strike System (US) 

PM post meridian (after noon) 

PMB Programme Management Board (Galileo) 

Pmd probability of missed detection (eg in RAIM) 

PMO Port Meteorological Office(r) 

PMoU Paris Memorandum of Understanding (EU shipping standards) 

Includes Black, Grey and White lists. 

PMR private mobile radio (PMR446 is EU standard) 

Up to 3 km range; no licence needed. 

PMS planned maintenance system (shipping) 

PMU portable mobile unit (part of PPU) 

PMU processing and monitoring unit 

P N 

north geographic pole 

PN pseudo-noise 

PNAV Precise NAVigation 

PND portable/personal navigation device (typically a PDA) 

PND primary navigation display 

PNF Polish Navigation Forum 

PNM pedestrian navigation module 

PNR Passenger Name Records (EU) 

PNR passive noise reduction 

PNR point of no return 

PNR prior notice required 

PNT position, navigation and timing (or position, navigation, time) 

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March 2012

PNT Exec Ctee US National Space-Based Positioning, Navigation & Timing Exec Ctee 

Chaired jointly by Dep Secs of Defense and Transportation. 

Members: Depts of State, Commerce, Homeland Security, JCS & 

NASA. Under 2004 Presidential Directive. Ex-IGEB. 

PO dust devils (met) 

POB persons on board 

POB pilot on board 

POC proof-of-concept 

POD precise orbit determination 

POEMS Pre-Operational European Mode S Station (EUROCONTROL) 

POI point of interest (LBS) 

POINT Position Orientation INTegration (software for UAV nav fm GRC) 

POP period of operation 

POP point of presence (local area node joining WLAN to trunk network) 

POP Post Office Protocol (Internet) 

POR Pacific Ocean Region (Inmarsat satellite) 

POS/LV Position & Orientation System for Land Vehicles 

POS/NAV positioning and navigaion 

PoSAT Portugese Satellite (-1 carries GPS experiments) 

POSSUM Policy Scenarios for Sustainable Mobility (EU) 

Postcode Units by which delivery of post is managed (Royal Mail) 

In UK comprises Area (eg SW), District (7), Sector (2) and Unit (AT) - 

hence SW7 2AT. 

POTS plain old telephone system! 

PP positioning performance 

PPC predicted/potential point of collision 

PPD personal privacy/protection device (typically a GNSS jammer) 

PPD pilot preference downlink 

PPD Presidential Policy Directive (US) 

PPE personal protective/protection equipment 

PPI plan position indicator 

PPL( ) Private Pilot’s Licence 

(A) = aircraft, (B) = balloons, (H) = helicopters, A(M) = microlights. 

ppm parts per million 

PPM pulse position modulation 

PPP precise point positioning 

PPP public-private partnership 

PPPS pulse pairs per second (DME. TACAN etc) 

PPS Precise Positioning Service 

The full accuracy positioning service provided to the military by GPS. 

Includes access to unencrypted P-Code transmissions. 

PPS pulses per second 

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March 2012

PPS-SM PPS Security Mode/Module 

PPU pilot portable unit (marine) 

PR banks (met) 

PR pseudo-range (GPS) 

Range measured between a rx and GPS sat, including all errors & bias. 

PRARE precise range and range-rate equipment (marine) 

PRC Perfomance Review Commission (EUROCONTROL) 

PRC primary reference clock 

PRC pseudo-range correction 

precision The accuracy of a measurement or a position with respect to random 

errors (IMO). 

Precision Approach A standard instrument approach procedure in which both horizontal 

and glidepath/slope guidance is given. 

PRESERVE Preparing Secure Vehicle-to-Infrastructure Communication Systems 

EU research project launched Feb 11. 

PReVENT EU IP for preventive & active safety systems (DG Info Society) 

PRF pulse repetition frequency 

PRI pilot receiving instruction (US air) 

PRIMAR The formal service delivered by RENCs (established 1999) 

Primary Means of 

Navigation 

Airborne nav system that must meet accuracy and integrity 

requirements but need not meet full availability or continuity-ofservice 

requirements. 

Prime meridian Reference meridian 000º; origin for measurement of longitude 

Also known as the Greenwich Meridian. The most enduring definition 

was by Sir George Airy in 1851; this has been replaced by that of WGS 

-84, which is about 102 metres to the east. 

PRM preferred route message (North Alantic ATC) 

PRN pseudorandom noise (code) 

Deterministic binary sequences with noise-like properties, also called 

pseudonoise codes. Used in spread-spectrum comms and ranging 

transmissions. GPS C/A and P-Code are PRN codes. 

PRNAV precision RNAV for terminal areas (ICAO) 

PROB probability (met) 

ProGIS Promoting Geographic Information Systems (Finnish AGI) 

PRoGRESS Urban RUC demo & research project (EU-funded) 

PROMISE Pre-operational Modelling in the Seas of Europe (EU MAST III proj) 

PROVESS Processes of Vertical Exchange in Shelf Seas (EU MAST III proj) 

PRR pseudo-range rate 

PRS primary reference source (eg ANSI Stratum 1, GPS or eLoran) 

PRS Public Regulated Service (Galileo) 

Uses OS plus 2 encrypted signals giving controlled access and high 

continuity. The ‘military’ signal. 

PRT personal rapid transit 

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March 2012

PRU Performance Review Unit (EUROCONTROL) 

P S 

south geographic pole 

PSAP public safety answering point (for eCall type applications) 

PSC Port State Control 

PSD power spectral density 

PSDR preliminary system design review 

Pseudo-range Pure geometrical range between satellite and observer, corrupted by 

clock offsets, atmospheric errors and other error sources. 

Pseudolite Pseudo-satellite 

Ground-based transmitter designed to mimic a satellite (GPS). 

PSF performance shaping factor (of human behaviour in HRA) 

PSM power save mode (eg chip) 

PSMA Public Sector Mapping Agreement (OS for England and Wales) 

PSMSL Permanent Service for Mean Sea Level 

PSoc Photogrammetric Society (became RSPSoc on 1 Jan 01) 

PSR primary surveillance radar 

PSS packet switching stream 

PSSA Particularly Sensitive Sea Area 

PSSA preliminary system safety analysis 

PSTN Public Switched Telephone Network 

PSU power supply unit 

PTAN precision terrain-aided navigation 

PTC Positive Train Control (US DOT initiative) 

PTF precise timing facility 

PTFM passive traffic flow measurement (eg Trafficmaster) 

PTP packet time protocol (eg PTP IEEE-1588v2 in 2008) 

PTP personal travel planning (schemes for pedestrians) 

PTS Polar Track Structure 

PTS Precision Timing System/Station (Galileo) 

PTT platform transmitter terminal (eg tracker for animal) 

ptt press-to-transmit 

PTTI precise time and time interval 

PUFFIN Pedestrian User-Friendly INtelligent crossing (UK DTLR) 

PUIN Russian military air nav backup system based on GLONASS 

PUNE position component of the user navigation error (3-dimensional) 

PV pilot vessel 

PV prime vertical 

PVA position, velocity and acceleration (mode of op of integrated system) 

PVT Position, Velocity and Time (Galileo Service) 

PVTA position, velocity, time and attitude 

PWC personal water craft (jetski) 

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PWSA Ports and Waterways Safety Act (US) 

PWSCG Public Weather Service Commissioning Group 

PZ-90 Soviet geocentric co-ordinate system used by GLONASS (SGS90) 

Q quadrature component 

QAR quick-access recorder (air) 

QBC Quality Bus Corridor (initiative in Glasgow) 

QCA Qualifications and Curriculum Authority (UK) 

Formed in 1997 by the Education Act 1997. 

QDM magnetic bearing to a DF station 

QDR magnetic bearing from a DF station 

QFE atmospheric pressure at aerodrome elevation 

QFI qualified flying instructor 

QFN quad-flat no-leads (ic packaging) 

QFU runway orientation (magnetic) 

QGH controlled descent through cloud 

QGO airfield closed due to weather 

QHM Queen’s Harbour Master 

QinetiQ The private arm of DERA from 2 Jul 01 

A nonsensical name taken from the Greek ‘kinetikos’ - to move. 

QINS QinetiQ Integrated Navigation Simulation 

QNH atmospheric pressure at sea level 

QoS quality of service 

QPSK(m) quadrature phase shift keying (with chip rate of m x 1.023 Mcps) 

QRH quick reference handbook (eg with AOM) 

QSW quiet space weather (assumption for GPS ionospheric delay mode;) 

QSY change frequency 

QTAS QinetiQ Transfer Alignment Simulation 

QTE true bearing from DF station 

QUATTRO Quality Approach in Tendering/Contracting Urban Public Trans Ops 

An EC project Dec 96 - May 98. 

QZSS Quazi-Zenithal Satellite System (Japan) 

3-satellite positioning system to supplement and interoperate 

with GPS. First launched Sep 10, the 2nd & 3rd due in 2012. 

R ºRelative 

R-GEO GEO ranging 

GEO-based GPS-like ranging signal (as in EGNOS). 

R-IORS re-entrant integrated optical rotation sensor 

R/T (RT) radio telephony 

R&D research and development 

R&E research and engineering 

R&RNAV Research and Radionavigation Directorate (GLAs) 

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March 2012

R&TTE Radio Equipment & Telecommunications Terminal Equipment Directive 

EC legislation applying to vehicles. Mandatory from 8 Apr 01. 

R2V roadside-to-vehicle (eg comms) 

RA Radiocommunications Agency (UK) 

Established as an Executive Agency of the DTI in 1990. Transfer to 

Ofcom 29 Dec 03. 

RA rain (met) 

RA resolution advisory (ACAS/TCAS II) 

RA right ascension 

RA(T) Restricted Area (Temporary) 

Established temporarily around airshows and other events. 

RA2 Regulatory Approach to Recreational Aviation (UK CAA) 

RAAN right ascension of the ascending node 

Equatorial angle from a celestially-fixed direction to the ascending 

node of a satellite orbit. Higher orbit gives lower rate - GPS = 

14.15º/year, Galileo = 9.01º/year. Hence constellations will drift 

relative to each other at 5.14º/year. 

RAAS Regional Area Augmentation System 

RAC Royal Automobile Club (UK) 

RACON RAdar beaCON (active radar beacon or transponder) 

RACS road-automobile communication system 

rad radian (180/ degrees) 

Radar RAdio Detection And Ranging 

radio 

determination 

The determination of position, or the obtaining of information relating 

to position, by means of the propagation properties of radio waves 

(IMO). 

radiolocation Radio determination used for purposes other than radionavigation 

(IMO). 

radionavigation The use of radio waves in navigation for the determination of position 

or direction, or for obstruction warning (IMO). 

RAeC Royal Aero Club of the United Kingdom 

RAeS Royal Aeronautical Society 

RaFFLES Radio Frequency Functional Level Evaluation Suite (UK NATS) 

RAFS rubidium atomic frequency standard 

RAFS EU rubidium atomic frequency standard evaluation unit 

RAI Registro Aeronautico Italiano (Italian CAA) 

RAIB Rail Accident Investigation Branch (UK) 

RAIDS Rangeless Airborne Information Datalink System 

RAIM receiver autonomous integrity monitoring 

A technique whereby all navigation sensor information available at a 

receiver is autonomously processed to monitor the integrity of the 

navigation signals (IMO). 

RAL Rutherford Appleton Laboratory (Oxford) 

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RAM random access memory 

RAM reliability and maintainability 

RAMARK radar marker beacon 

RAMS reliability availability, maintainability and safety 

random error That error which can be predicted only on a statistical basis (IMO). 

Rapid/Mocha Rapid Climate Change/Meridional Overturning Circulation and 

Heatflux Array) project 

RAR real aperture radar 

RAS radar advisory service (ATC) 

RAS Radio Astronomy Service (of allocated spectrum bands) 

RAS rectified airspeed 

RAS regional augmentation system 

RAS replenishment at sea 

RAT Risk Awareness Tool (FSF) 

RAVI Netherlands Council for Geographic Information 

RBDS radio broadcast data system 

RBI relative bearing indicator 

RBN radio beacon 

RCC real to complex convertor (signal processing) 

RCC Rescue Co-ordination Centre 

RCD Recreational Craft Directive (EU) 

RCDS raster chart display system 

RCL runway centre line 

RCM reliability centred maintenance 

RCP required communications performance 

RCS radar cross-section (normally givien in square metres) 

RCVR receiver (or Rx) 

RD requirements document/definition 

RDA Regional Development Agency (UK) 

RDBMS Relational Database Management System 

RDC Research & Development Center (USCG) 

RDF radio direction find(er)(ing) 

RDS Radio Data System 

Sub-carrier on FM broadcasts carrying data, which may include DGPS 

corrections and TMC. 

RDS-EON Radio Data System - Enhanced Other Networks 

Digital traffic messages carried by RDS. 

RDS-TMC Radio Data System - Traffic Message Channel 


RDSS Radio Determination Satellite Service 

RDT&E research, development, test and evaluation 

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REACH Registration, Evaluation, Authorisation and Restriction of Chemical 

Substances (marine regulations) 

READ RIMS Entities Assistance Desk 

RECNET RECeiver NETwork (eg EGNOS) 

REDAN REd de Datos de Aeropuertos y Navegación (Spanish aero comms net) 

redundancy The existence of multiple equipment or means for accomplishing a given 

function (IMO). 

REG Red Engign Group (entitled to fly the Red Ensign/amended version) 

Anguilla, Bermuda, British Virgin Islands, Cayman Islands, Falkland 

Islands, Gibraltar, Guernsey, Isle of Man, Jersey, Montserrat and St 

Helena, Turks and Caicos Islands, United Kingdom. 

REGAL REconfigurable REceiver for GALileo 

REIL runway end identifier lights 

relative accuracy The accuracy with which a user can determine position relative to that 

of another user of the same navigation system at the same time (IMO). 

reliability (of a position fix) 

A measure of the propagation of a non-detected gross error in an 

observation, to the position fix. This ‘external’ reliability is usually 

expressed in terms of the MDE (IMO). 

reliability (of a service) 

The probability that a service, when it is available, performs a 

specified function without failure under given conditions for a 

specified period of time (IMO). 

reliability (of an observation) 

(‘internal’ reliabilty). A measure of the effectiveness with which gross 

errors may be detected. Ususally expressed in terms of the MDB 

(after IMO). 

RENC Regional Electronic Chart Coordinating Centre 

Provide a single source for all countries’ ENC data. The Northern 

Europe RENC is at Stavanger, Norway. Service known as PRIMAR. 

repeatability The accuracy of a positioning system, taking into account only the 

random errors. Normally expressed in a 95% probability circle (IMO). 

repeatable 

accuracy 

The accuracy with which a user can return to a position whose 

coordinates have been measured at a previous time with the same 

navigation system (IMO). 

RESCU 2nd generation in-vehicle nav system (GPS + GSM) (Ford) 

RF radio frequency 

RF range finder 

RF route to a fix 

RFF Rescue and Fire Fighting (Category of airfield facilities) 

RFFE RF front end 

RFFS Rescue and Fire Fighting Service (airport) 

RFI radio frequency interference 

RFI request for information 

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March 2012

RFID radio frequency identification (tags - typically use 13.56 MHz) 

RFP request for proposal 

RFSINS rotary FOG-based strapdown inerial navigation system 

RFU radio frequency unit 

RGB Red-Green-Blue (colour system for colour monitors) 

RGCSP Review of the General Concept of Separation Panel (ICAO) 

RGPF Règlement Gènèral de Police Français (French derivative of CEVNI) 

RHA Road Haulage Association Ltd (UK) 

RHCP right hand circularly polarised / circular polarisation 

RHINO Receiver for High Integrity Navigation Operation (Raytheon) 

RHL rhumb line 

RHS right hand seat (cockpit) 

RHUM relative humidity 

RI restricted information (eg value-added data on chart) 

RIA Regulatory Impact Assessment (UK requirement) 

RIB rigid infalatable boat 

RID Regulations on international carriage of dangerous goods by rail 

RIG rate integrating gyro 

RIMS Ranging and Integrity Monitoring Station (EGNOS has 12) 

RIN Royal Institute of Navigation 

RINA Registro Italiano Navale (classification society) 

RINA The Royal Institution of Naval Architects 

RINEX Receiver-INdependent EXchange (format for exchanging GPS data) 

RIS radar information service (ATC) 

RIS River Information Service (telematics) 

RISA reduced instruction set architecture 

RISC reduced instruction set computer 

RISDE Rossiyskogo Institute of Space Device Engineering (GLONASS) 

RISG Runway Incursion Steering Group (UK CAA) 

RITA Research and Innovative Technology Administration (USA) 

RL rhumb line (loxodrome) 

Line on the surface of the earth forming the same angle with all 

meridians; a straight line on a Mercator chart. 

RLD Rijksluchtvaartdienst (Netherlands CAA) 

RLG ring laser gyro (introduced ~ 1975) 

RLM return link message 

RLP rejected landing procedure 

RLSS Royal Life Saving Society (UK) 

RM reference model 

RM relative motion 

RMA reliability, maintainability, availability 

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March 2012

RME range measurement equation 

RMES root mean error Square 

RMI radio magnetic indicator 

RMRS Russian Maritime Register of Shipping 

rms root mean square (error) 

The variability of a measurment such as a single LOP in one dimension; 

with no bias also an estimate of the standard deviation of the errors. 

rmse root mean square error (see rms) 

RMT National Union of Rail, Maritime and Transport Workers (UK) 

RMU radio management unit 

RNAS Royal Naval Air Station 

RNAV area navigation 

A method of navigation which permits aircraft operation on any 

desired flight path within the coverage of station-referenced 

navigation aids, or within the limits of the capability of a selfcontained 

navigation system, or a combination of these. 

RNC raster navigational chart 

RNEU Radio Navigation Experimentation Unit (ESA) 

rng range 

RNLI Royal National Lifeboat Institution 

RNN RadioNavigeringsNamnden (Swedish Radio Navigation Board) 

Formed in 1950 with ~ 20 governmnent, institutional and commercial 

members. Applied for EUGIN membership 2003. 

RNP radionavigation plan 

RNP required navigation(al) performance 

A statement of navigational performance necessary for operation 

under specified conditions. Covers accuracy, availability, integrity and 

continuity of service. RNP-X (X = 95% prob accuracy in NM). 

RNP Required Navigation(al) Performance Study Group (ICAO) 

RNS RadioNavigation Service (of allocated spectrum bands) 

RNS relative navigation system 

RNSS RadioNavigation Satellite Service 

ROB remain on board 

ROC rate-of-climb 

ROC required obstacle clearance (eg TAWS) 

ROC Restricted Operator Certificate (GMDSS) 

ROHS Restriction of Hazardous Substances (EC Directive) 

ROM read-only memory 

ROMANSE Road Management System for Europe (EU) 

ROP responsible operator position (in SAR) 

RoPax As RoRo ferry but with 12+ pax and treated as a passenger vessel 

ROPME Regional Organisation for the Protection of the Marine Environment 

RoRo Roll-on, roll-off ferry (

RoS Registers of Scotland (= HMLR) 

ROT (RoT) rate of turn 

ROV remotely operated vehicle 

ROW rest of the world 

RP radar plotting 

RP reporting point 

RPER radial position error rate 

RPIN Russian Public Institute of Navigation 

RPK revenue passenger kilometres (a measure of civil air actual traffic) 

RPNR Règlement de Police pour Navigation du Rhin (Rhine deriv of CEVNI) 

RPS Regional Positioning System (to provide WAAS in a particular area) 

RPS Regional Pressure Setting 

RR Radio Regulations (ITU) 

RR reference receiver (eg LAAS) 

RRC range-rate correction 

RRC root raised cosine (shape of an autocorrelated pulse in navsat sig) 

RRI Road Routing Information (theme of ITN) 

RS radio spectrum 

RS ranging source (eg WAAS) 

RS reference station (eg LAAS) 

RS remote sensing 

RS Russian Maritime Register of Shipping (classification society) 

RSA recognised spectrum access 

RSA relative speed across track 

RSA Rivest-Shamir-Adleman (public-key algorithm) 

Signing and verifying procedure in Digital Signal Standard (RSA-DSS). 

RSA Russian Space Agency 

RSC reusable software component 

Formal acceptance for reusability - US FAA certification. 

RSD radar system data 

RSIM reference station integrity monitor 

RSL relative speed along track 

RSM reduced separation minima (air traffic) 

RSME Rating Scale Mental Effort (to measure subjective workload) 

RSN Robust Surface Navigation (US Army - using ‘signals of opportunity’) 

Exploiting satellites, cell phone and television transmitters to 

provide precise location and navigation information to ground 

troops when GPS is jammed or blocked. 

RSO Range Safety Officer 

RSPG Radio Spectrum Policy Group (EC) 

RSPP Radio Spectrum Policy Programme (EU) 

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RSPSoc Remote Sensing and Photogrammetry Society 

Formed 1 Jan 01 from RSS and PSoc. Based Nottingham University. 

RSS Really Simple Syndication (delivers webste info directly to PC) 

RSS received signal strength 

RSS Regional Safety Service (Galileo) 

RSS Register of Shipping and Seamen 

RSS Remote Sensing Society (became RSPSoc on 1 Jan 01) 

rss root sum square 

RSS Russian Space Systems 

RSSB Rail Safety and Standards Board (UK) 

RSSI received signal strength indicator 

RT (R/T) radio telephony 

RT Ranging and Timing (Galileo service) 

RT remote terminal 

RTA required time of arrival (ATC) 

RTA Research and Technology Agency (NATO - part of RTO) 

RTA Road Traffic Advisor (UK collaborative project led by TRL) 

Test bed uses 350 km of road between Swansea and Gatwick. 

RTB Research and Technology Board (NATO - part of RTO) 

RTB return to base 

RTC real time clock 

RTC required terrain clearance (eg TAWS) 

RTCA Radio Technical Commission for Aeronautics (US) 

RTCM Radio Technical Commission for Maritime Services (US) 

RTCM SC-104 developed the recommended standards for DGPS. 

RTD Research and Technological Development (EU transport projects) 

RTE radar target enhancer (transponder on target) 

RTE route 

RTF radio telephony 

RTI road traffic informatics (sometimes ‘infrastructure’) 

RTK real-time kinematic 

A DGPS procedure whereby carrier-phased corrections are 

transmitted in real time from a reference rx to user’s rx. 

RTMT read the manual training! 

RTO real-time operating system 

RTO rejected takeoff 

RTO Research and Technology Organisation (NATO = RTB + RTA) 

RTOD real-time precise orbit & clock determination 

RTOS real-time operating system 

RTPI real-time passenger information (for buses etc) 

RTS Raunch-Tung-Striebel (algorithm used to smooth Kalman filter) 

RTT round trip time 

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March 2012

RTTI real-time traffic information 

RTTT road transport and traffic telematics 

RTZ return to zero 

RU receiving unit 

RU rover unit 

RUC road user charging (a form of EFC) 

RULES RA Unified Licensing Executive System 

RVR runway visual range 

RVSM reduced vertical separation minima 

eg ICAO proposal to reduce vertical separation between aircraft from 

FL290 to FL410 from 2,000 to 1,000 ft. Introduction in 

EUROCONTROL 24 Jan 02. 

RW random walk (Kalman filter technique) 

RW runway 

RWD relative wind direction 

RWS relative wind speed 

Rwy runway 

Rx (RCVR) receiver 

RYA Royal Yachting Association 

s second 

S-57 Standard for exchange of ECDIS data (IHO) 

S-AIS Space-based Automatic Identification System 

S-band Old radar band 2-4 GHz = 15-7.5 cm 

(ITU assigned 2,300-2,500 & 2,700-3,700 MHz). 

S-CRPA small controlled reception pattern antenna 

S-VDR simplified voyage data recorder (possible retrofit for older ships) 

S@tcom BNSC programme (includes sponsorship of Galileo Partnership) 

S/N signal-to-noise ratio 

S/N 0 

signal-to-noise density ratio 

S&P simulation & prediction 

S&R (SAR) search and rescue 

SA (S/A) Selective Availability 

The intentional degradation of the GPS Standard Positioning Service. 

Was set to give 95% prob accuracies of 100m (300m 99.99% prob) 

horizontal, 156m vertical and 334ns in time. Set to zero on 1 May 

2000. 

SA sand (met) 

SA Specific Activity (EU FP6) 

SA system architecture 

SAAAR Special Aircraft and Aircrew Authorisation Required (runway app’ch) 

SaaS Software as a Service (cloud computing) 

SAASM selective availablility anti-spoofing module 

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March 2012

SAC Special Area of Conservation (EU Habitats & Bird Directives) 

SADIS SAtellite DIStribution System (Met) 

Provides point to multi-point real-time met data. 

SAED selected area electron diffraction 

SAFA Safety Assessment of Foreign Aircraft (EU) 

SAFEMAR Development project for ship reporting system (MARIS) 

SafeSeaNet System to monitor vessel movements and permit the exchange of 

vessel data between EU Member States. 

Safety Regulation Definition & enforcement of rules relating to safety 

SafetyNET Satellite-based service for promulgation of nav and met 

warnings, met forecasts, SAR info and urgent safety-related 

messages – maritime safety information (MSI) – to ships. 

SAFI semi-automatic flight inspection 

SAG single axis gyroscope 

SAGA Standardisation Activities for GAlileo 

Platform for establishing world-wide interoperability between Galileo 

and other systems. Consortium led by Sextant Avionique. 

SAIF Submeter-class Augmentation with Integrity Function (QZSS) 

SAL supplementary approach lighting 

SAM methodology for safety assessment 

SAM System Area Monitor (eg LORAN) 

SAMSA South African Maritime Safety Authority 

SAMSO Space and Missile Systems Organization (US) 

SAP system access parameter (SSR Mode S) 

SAPPHIRE Satellite & Aircr’ft Database Project for System Integrity Research 

EUROCONTROL project. 

SAR (S&R) search and rescue 

SAR synthetic aperture radar 

SARGAL study for Search And Rescue in GALileo (EC) 

SARIS Search and Rescue Information System (SARIS II current fm 2003) 

SARPS Standards and Recommended Practices (ICAO) 

SARSAT SAR Satellite-Aided Tracking 

SART search and rescue transponder (marine) 

Shows as 12 dots beyond target when activated by ~9 GHz radar. 

SAS Safety Access Service (Galileo) 

Requirements for aviation safety-critical applications include: 

En-route & non-precision approach: 45m hor, 15m vert, alert time 30s. 

Cat I precision approach: 16m hor, 4-7.7m vert, alert time 6s. 

Cat II/III precision appraoch: 6m hor, 1m vert, alert time 1s. 

SAS safety at sea 

SAS standard altimeter setting (1013.2 mB or 29.92 in Hg) 

SASWG Spectrum and Surveillance Working Group (CAA) 

SAT Office of Space and Advanced Technology (US) 

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March 2012

SAT satellite tag (eg for animal) 

SAT signal analysis tool 

SAT site acceptance test 

SAT static air temperature 

SATCO senior air traffic control officer 

SATHIA SATellite Hyperbolic Intersection Algorithm (for integrity) 

SATNAV satellite-based navigation 

SATR Static Antenna Test Range (for GPS jamming tests - US) 

SATURN Consortium researching GNSS quality of service solutions 

Chronos Technology Ltd, University of Bath, NPL. 

SATURN SATellite-based aUtonomous tRain localisatioN system 

SAVAA Support to Aviation for Volcanic Ash Avoidance (ESA project) 

SBAC Society of British Aerospace Companies Ltd 

SBAS satellite-based augmentation system 

SBB smart buffer box 

SBC single board computer 

SBCN space-based communication network (GNSS) 

SBEN space-based external navigation (system) (GNSS) 

SBM single buoy mooring 

SBNS satellite based navigation system 

SC sector controller (ATC) 

SC service centre (GNSS) 

SC Special Committee (eg RTCM SC-104) 

Sc stratocumulus cloud 

SCAAR State Civil Aviation Authority of Russia 

SCADA supervisory control and data acquisition 

SCAR Scientific Committee on Antarctic Research 

SCAR software component acceptance review 

SCART Syndicat des Constructeurs d’Aparcils Radiorecépteurs de 

Also known as Peritel or Euroconnector (for video). 

SCAT-1 Special CAT 1 (ILS) 

Scatterometer An instrument which measures dispersal 

SCAWVEX Surface Current and Wave Variability Experiment (EU MAST II) 

SCDM System of Differential Correction & Monitoring (GLONASS) 

Uses LUCH geo satellites to provide differential corrections. 

SCDS ship control display system 

SCF Satellite Control Facility (Galileo) 

SCH set clearance height (ATC) 

ScOACC Scottish and Oceanic Area Control Centre (ATC) 

SCOOT Split, Cycle and Offset Optimisation Technique 

Controlling traffic signals automatically to reflect trafic flow. 

SCOPIC Special Compensation P&I Clause 

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March 2012

SCOR Scientific Committee on Oceanic Research 

SCOS Satellite Control and Operations Support (ESA) 

Hard/software system for controlling single/multi satellites. SCOS 

-2000 is latest version, used in many systems, including Galileo. 

SCT scattered cloud (3-4 oktas) 

SCU signal conditioning unit 

scUK sports coach UK (trading arm of the NCF) 

SCW swept continuous wave (transmission, often a form of jamming) 

SD semi-diameter (astro) 

SD single-differencing (GNSS relative positioning) 

SD standard deviation 

For a normal linear distribution 68% of readings should lie within 1 SD 

and 95% with 2 SDs. 

SDCM System of Differential Correction and Monitoring (GLONASS) 

SDF single degree of freedom 

SDGPS Smoothed DGPS 

SDI spacial data infrastructure 

SDK software development kit 

SDLC synchronous data link control 

SDME speed and distance measuring equipment (maritime) 

SDMMC secure digital multimedia memory card 

SDO selective door operating (rail) 

SDO service data object 

SDO Solar Dynamics Observatory 

Sat launched 11 Feb 10 to study Sun from geo orbit for 5+ years. 

SDR software-defined radio 

SDR system design review 

SDS Safety Data Sheet (marine) 

SDSL Symmetric Digital Subscriber Line 

For Web access using normal phone lines at speeds up to 2.3 Mbps. 

SDST Single-Double Summer Time (UK - GMT+1 for winter, +2 for summer) 

SDTS spacial data transfer standard 

SEA strategic environmental assessment 

Sea Areas A1-A4 GMDSS areas repressenting differing coverage 

A1 - within RT range of at least one VHF coast station in which 

continuous DSC alerting is available. 

A2 - excludes A1, but covered by at least MF coast station with 

continuous DSC alert. 

A3 - outside A1 & A2 but covered by Inmarsat with continuous alert. 

A4 - outside A1, A2 and A3. 

SEC Space Environment Center (US) 

SECA SOx Emission Control Area (to control ships’ sulpher emissions) 

SED storm enhanced density (of ionosphere) 

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March 2012

SEE South East Europe 

Seiche The oscillation of a body of water at its natural period, 

superimposed on normal tidal changes. 

SEIFR single-engine IFR 

Selcal selective calling (HF and VHF) 

SELS Southern Europe LORAN-C System 

SEM standard errors of medians (statistics) 

SENC system electronic navigation chart 

SEP spherical error probable 

The radius of a sphere, centered at the measured position, inside 

which the true position lies with 50% probability. 

SeqSLAM Sequence Simultaneous Localisation and Mapping 

SER sequence-of-events recorder 

SERA Standardised European Rules of the Air (EUROCONTROL fm 2012) 

service capacity The number of users a service can accommodate simultaneously (IMO). 

SES satellite/ship earth station 

SES Shelf Edge Study (part of LOIS project) 

SES Single European Sky (EC/EUROCONTROL project) 

SESAME Project to create a European ATM roadmap 

SESAR Single European Sky ATM Research (EUROCONTROL for 2020+) 

Definition phase in 2006; involves a consortium of 16 EC 

Members and 70 companies in 300 projects. 

SET selective event training (of simulation) 

SET Sensors and Electronics Technology Panel (NATO RTO) 

SETS Spectrum Engineering Tracking System (US - for GPS jamming) 

SF scale factor 

SF secondary factor (cause of Loran signal delay - also PF and ASF) 

SF static field 

SF stride frequency 

SFC single frequency channel 

SFD satellite failure detection (component of SBAS) 

SFF small form factor 

SG snow grains (met) 

SG symbol generator 

SGEE server generated external ephemeris (EE) file 

SGF Space Geodesy Facility (formally SLR) 

Worldwide series of laser rangers measuring satellie heights up to 

19,000 km to about 1 cm accuracy. UK one based at Herstmonceux. 

SGR skywave-to-groundwave ratio (of RF transmission) 

SH showers (met) 

SHA siderial hour angle 

SHAG Small Helicopter Advisory Group (CAA) 

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March 2012

SHIPPOS SHIP POSitioning Reporting Service 

SHOM Service Hydrographique et Oceanographique de la Marine (FR) 

SI Surveillance Identifier (SSR Mode S Code) 

SI Système Internationale d’Unités 

International system of units, the outcome of the 9th General 

Conference of Weights and Measures in 1948. 

SIA French Aeronautical Information Service 

SIAP standard instrument approach procedure 

SIC second in command (co-pilot or first officer (air)) 

SID standard instrument departure 

SID sudden ionospheric disturbance 

SIF selective identification feature (ATC secondary radar) 

SIG GIS (geographic information systems) in many languages 

SIG Special Interest Group (RIN) 

sigma Greek letter s normally used for standard deviation 

SIGMET Significant Meteorological Report 

SIGTTO Society of International Gas Tanker and Terminal Operators 

SIGWX significant weather 

SIL safety integrity level 

SIL system integration laboratory 

SIM subscriber identification module 

SIMRAN Satellite Imaging for Rail Navigation 

SIMRSN Singapore Integrated Multiple Reference Station Network 

simTD Safe and Intelligent Mobility–Test Field Germany (2012 project) 

SINCTA ATCOs’ union in Portugal 

single point of 

failure 

That part of a navigation system which lacks redundancy, so that a 

failure in that part would result in a failure of the whole system 

(IMO). 

SINR Signal to Noise plus Interference Ratio 

SINS shipborne/strapdown INS 

SIOM standard input/output module 

SIP session initiation protocol 

SIP single in-line package (chip) 

SIPT Société internationale de photogrammétrie et de télédétection 

(ISPRS). 

SIR signal-to-interference ratio 

SIRC Seafarers International Research Centre (Cardiff University) 

SIReNaC Database holding ships’ info under the Paris MOU 

SIRU space inertial reference unit 

SIS signal-in-space 

SISA signal-in-space accuracy 

SISE signal-in-space error 

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March 2012

SISMA signal-in-space monitoring accuracy 

SISNeT Signal-In-Space through the interNeT (ESA project for EGNOS) 

SIU secure interface unit 

SiVSG Silicon Vibrating Structure Gyro (BAe) 

SKC sky clear (met) 

SKYCONTROL ATCOs’ union in Switzerland 

sl (s/l) sea level 

SL step length 

SLA Service Level Agreement (eg for Galileo) 

SLD styled layer descriptors (ofWMS) 

SLD superfluorescent laser diode 

SLR satellite laser ranging (now called SGF) 

SLS Satellite Landing System 

SLV solar light vessel 

SMAC Scene-Matching & Area Correlation (System) 

SMAG Spectrum Management Advisory Group (RA NDPB) 

SMART Self-Managed Arrival Resequencing Tool (MITRE for FAA) 

SMART Summing Multiple Artificial Radio Transmitters Trigonometrically 

A VBM Fourier technique for simulating multiple GPS jammers. 

SMarT Support for Maritime Training Scheme (UK) 

Smartnav In-vehicle satnav using Trafficmaster 

SmartNet Uses NRTK with 142 CORS in UK & Ireland (2008) 

SMC Safety Management Certificate (ISM Code) 

SMC Space and Missiles Center (USAF) 

SMD smart mobile device 

SME small and medium-sized enterprise(s) 

SMEF System Management & Engineering Facility (LSU) 

SMF separation monitoring function (ATC) 

SMG speed made good (speed (of ship) between 2 fixes) 

SMGCS Surface Movement Guidance & Control System (for airfields) 

SMI small and medium-sized industries 

SMLC serving mobile location centre 

GSM network centre that handles the location for handsets. 

SMLC summer mountain leader certificate 

SMO spectrum management organisation 

SMRS surface movement radar system (airfields) 

SMS safety management system 

SMS Short Message Service (brief text messages over mobile phones) 

SN snow (met) 

SNAFU situation normal: all fouled up (this is the polite version . .) 

SNAG Satellite Navigation Applications Group (EUROCONTROL) 

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March 2012

SNAS Satellite Navigation Augmentation System (Chinese WAAS) 

SNCTA ATCOs’ union in France 

SNF satellite navigation frame 

SNMTT Satellite Navigation and Mobile Telephone Technology (CARDME) 

SNPWG Standardisation of Nautical Publications Working Gp (IHO CHRIS) 

SNR signal-to-noise ratio 

SNS standby navigation system 

SNU standard navigation unit 

SOA Silicon Oscillating Acclerometer (for MEMS IMU - Draper Labs) 

SOA speed of advance (speed to make good) 

Estimated speed (of ship) relative to the earth. 

SOAP Simple Object Access Protocol (for OpenGIS) 

SoC system on chip 

SOCP Ship Operations Cooperative Program(me) 

Sponsored by the US Maritime Administration (MARAD). 

SOCRATES System of Cellular Radio for Traffic Efficiency and Safety (EU) 

SOG speed over ground 

Speed (of ship) relative to the earth, measured on board (the ship). 

SOGI Swiss Organisation for Geo-Information 

SOHO Solar and Heliospheric Observatory satellite (joint NASA/ESA) 

SOI signal of interest 

SOIT Satellite Operational Implementation Team (FAA) 

SOL safety of life 

SoL Safety of Life Service (Galileo) 

Fee-paying service providing integrity info as well as OS features. 

SOLAS Safety of Life at Sea (often SOLAS 74) 

IMO Convention of 1974. 

Sole Means of 

Navigation 

An approved system that must meet 4 performance requirements: 

accuracy, integrity, availability and continuity-of-service. 

SOM self organising map (of a neural network) 

SoOP signals of opportunity 

SOP standard operating procedure 

SoP Statement of Principles (EC inviting compliance by states) 

eg a 1999 one was on ‘HMI for in-vehicle telematics’. 

SOP surface of position 

SOPEP Shipboard Oil Pollution Emergency Plan 

SOSREP Secretary of State’s Rep for Marine Salvage and Intervention 

SOTDMA self-organising time division multiple access 

SOTIS self-organising traffic information system (ITS) 

SOURDINE French for ‘mute’. EC DGVII Project for reducing airport noise 

SP service (and content) provider (eg of telematics services) 

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March 2012

SP Standard Precision (GLONASS service) 

Accuracy 57-70 m hor and 70 m vert, vel 15 cm/s (99.7%). 

SPA Special Protection Area (EU Habitats & Bird Directives) 

SPAC Satellite Positioning Research and Application Centre (Japan) 

SPACE Seamless Positioning in All Conditions & Environments (Pinpoint proj) 

Nottingham University, Leeds University, Imperial College, University 

College London, EADS Astrium, CAA, Leica GeoSystems, Nottingham 

Scientific, OS, QinetiQ, BAE Systems, Thales. 

Space IGS Space Innovation and Growth Strategy (UK - 2010) 

Joint Government, industry and academia 20-year strategy for UK. 

SPACECOM US Space Command (Colorado Springs) 

SPAD signal passed at danger (railway) 

SPD speed (own (ship’s) speed in dead ahead direction) 

SPEED Support Platform for EGNOS Evolution and Development 

SpeedAlert EC (DG TREN) project to harmonise in-vehicle speed alert systems 

One-year project from May 2004. 

SPF Service Products Facility (Galileo) 

SPF single-point-failure 

SPI ship-port interface (IMO) 

SPI Surveillance Performance and Interoperability (EUROCONTROL) 

SPIRE Space Inertial Reference Equipment (US first airborne INS - 1953) 

SPL signal power level 

SPM single point mooring 

SPOC SAR Point of Contact 

Spoofing Broadcasting deliberately erroneous nav signals so receivers give 

the wrong position while appearing to be working correctly. 

SPOS Ship Performance Optimisation System 

SPOT Satellite Pour l'Observation de la Terre (GPS location messenger) 

SPRUC satellite positioning based road user charging 

SPS Standard Positioning Service of GPS 

The service available to civilian users with a stand-alone receiver 

having access only to the C/A code and L1 carrier. 

Sps symbols per second 

SPWG Strategic Planning Working Group (IHO) 

SQ squalls (met) 

SQL Structured Query Language (for databases) 

SQM signal quality monitoring 

SQS Safety Quality Management and Standardisation (EUROCONTROL) 

squawk to transmit via a transponder 

SQuID superconducting quantum interference device (microscopy) 

sr steradian (solid angle) 

SR1 small hail or snow pellets (met) 

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March 2012

SR2 sunrise 

SRA Strategic Rail Authority (UK) 

SRA surveillance radar approach 

SRC Safety Review Commission (EUROCONTROL) 

SRC Short Range Certificate (for GMDSS VHF equipment) 

SRD short-range device (eg electronic car key) 

Typicallly use 418 MHz in UK, 433.92 MHz in Europe. 

SRD system/software requirements document 

SRG Safety Regulation Group (UK CAA) 

SRGPS Shipboard Relative GPS (uses LAAS to replace radar) 

SRR Search and Rescue Region 

SRR short-range radar (usually for vehicles using 24 GHz UWB) 

SRR system requirements review 

SRS Shipboard Reference System (for deck landings) 

SRU shop-replaceable unit 

SS sandstorm (met) 

SS signal strength 

SS space segment 

SS spread spectrum 

SS sunset 

SSA Specific Support Action (EU FP6) 

SSA system safety analysis 

SSB single sideband 

SSC Single Sky Committee (EU) 

SSCC Safety Standards Consultative Committee (EASA) 

SSFC sequential single-frequency code system 

SSH sea surface height 

SSI small scale integration (of chips) 

SSKL ATCOs’ union in Slovenia 

SSL signal simulation level 

SSN SafeSeaNet (EU & EEA to exchange info on ship moves & cargo) 

SSOA Standby Ship Operators’ Association (became ERRVA in May 2000) 

SSOG solid-state optical gyro 

SSP synchronous serial port 

SSPA solid-state power amplifier 

SSR Sagnac sensing ring (of optical gyro) 

SSR secondary surveillance radar 

SSSI Site of Special Scientific Interest 

SST satellite-to-satellite tracking 

SST sea surface temperature 

SST supersonic transport 

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March 2012

SSTL Surrey Satellite Technology Limited 

St stratus cloud 

STABLE Sediment Transport and Boundary Layer Equipment 

Standard Time The legally established time for a given zone 

STAP space-time adaptive processing (eg to produce CRPA) 

STAR Standard Terminal Arrival Route 

STARS Standard Terminal Automation Replacement System (FAA) 

StB Simplifying the Business (IATA initiative) 

STC Supplemental Type Certification (FAA for equipment upgrades) 

STCA Short-Term Conflict Alert (System) (used in ATC centres) 

STCW Standards of Training, Certification & Watchkeeping for Seafarers 

Set in 1978 (STCW 78) and amended in 1995 (STCW 95). Manila 

amendments from 1 January 2012 will include ECDIS training. 

STDCDU standard CDU 

STDMA self-organising time-division multiple-access 

STEC slant total electron content (of ionosphere) 

STENAV A Galileo simulation facility (space, ground segment & user 

STEREO Solar TErrestrial RElations Observatory (2 sats to observe sun - 06) 

stick LORAN-C transmitter (as opposed to a transmitter pair) 

STNA Service Technique Navigation Aerienne (France) 

Stochastic Governed by the laws of probability 

STOWASUS Storm, Wave and Surge (EU MAST IV project) 

STP standard temperature and pressure (=ISA) 

STPM synchronizer time-pulse modulator (Chayka) 

Stratosphere Part of atmosphere from ~ 14-50 km 

Stratum Minimum performance requirements for digital network synch 

ANSI 1987 Standard. Stratum 1 = atomic standard with 

fractional frequency offset of 1 x 10 -11 or less. Stratum 2 = drift 

of less than 2.5 x 10 -11 per day. Stratum 3 = less than 3.7 x 10 -7 

per day. GPS & eLoran give Stratum 1 quality. 

STREP Specific Targeted Research Project (EC FP6) 

STREP Specific Targeted Research Projects (EU FP6) 

STRV Space Technology Research Vehicle 

STS ship-to-ship transfer 

STW speed through water (speed of ship relative to the water surface) 

STW Standards of Training and Watchkeeping (IMO Sub-Ctee) 

SUA special use airspace 

SUBC self-unloading bulk carrier 

SUC specific use contract 

SUCG Scottish Users’ Consultative Group (NLB) 

SUP south pole up (of a magnet) 

SUPL Secure User Plane for Location (protocol for A-GPS) 

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March 2012

Supplemental 

Means of Nav 

An approved system that can be used in conjunction with a Sole Means 

of Navigation. 

SURDOV Joint UK-French project to share data between Dover and Gris Nez 

SURNAV Système français de comptes rendus de movements 

French info and surveillance service for marine navigation. 

SUT Society for Underwater Technology (UK) 

Sv Sverdrup (flow of one million cubic metres of water per second) 

SV space vehicle (eg satellite) 

SV synthetic vision 

SVD singular value decomposition 

SVFR special visual flight rules 

SVG scalable vector graphics (eg for maps and charts) 

SVGA Standard display format of 800 x 600 pixels 

SVID space vehicle identificator 

SVS service volume simulation 

SVS synthetic vision system 

SVT stolen vehicle tracking 

SVT system validation test 

SWAN Sistemi softWare per Applicazioni di Navigazione (Italian Space Agy) 

SWEPOS Swedish permanent national GPS network (24 stations) 

SWIR short-wave infrared 

SWL safe working load 

SXGA Standard display format of 1,280 x 1,024 pixels 

SXI Solar X-ray Imager 

NASA/NOAA imager giving X-ray image of sun each minute for 

predicting solar flares. Carried on Goes-M. 

systematic error An error which is non-random in the sense that it conforms to some 

kind of pattern (IMO). 

T ºTrue 

T tera (SI unit multiplier of 10 12 ) 

T tesla (magnetic flux density in Wb/m 2 ) 

T-DMB terrestrial digital media broadcasting 

T&D test and development 

T&E test and evaluation 

T2CAS Terrain & Traffic Collision Avoidance System 

Uses GPS to give terrain avaidance as well as TCAS function. 

TA timing advance (method of Cellphone positioning) 

TA traffic advisory (ACAS/TCAS I & II) 

TA traffic alert (ACAS/TCAS) 

TA transition altitude 

TA Type Approval 

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March 2012

TAA technically advanced aircraft 

GA aircraft in which the pilot ‘interfaces with one or more computers 

in order to aviate, navigate or communicate’. Includes a minimum of an 

IRF-rated GPS with moving map and integrated autopilot. 

TAA terminal arrival area 

TACAN TACtical Air Navigation 

Military beaccon system giving bearing and range. 

TACIS Technical Assistance to the CIS (EU) 

TADS triple air data system 

TAF terminal aerodrome forecast 

TAI Temps Atomique International (International Atomic Time) 

Determined by comparison of atomic clocks around the world. Does not 

change with variations of earth rotation rate. Time unit is the SI 

second, ‘the duration of 9,192,631,770 periods of the radiation 

corresponding to the transition between 2 hyperfine levels of the 

caesium 133 atom’. TAI = Time (Loran) + 10s = Time (GPS) + 19s = UTC 

+ LS. 

TAO Tropical Atmospheric Ocean project 

70 buoys moored in the Tropical Pacific Ocean. 

TAP-T Telematics Application Programme - Transport Sector (EU) 

TARSUS Tactical Artillery Survey System (uses GPS) 

TAS true airspeed 

TAT total air temperature 

TAWS Terrain Awareness and Warning System 

TB true bearing (angular distance from TN to the object) 

TBO time between overhauls 

TBO trajectory-based operations 

TC telecommand (of satellite) 

TC terminal control (ATC) 

TC Tide Committee (IHO) 

TC true course (course to steer) 

The intended direction of movement (of a ship), defined by the angle 

between the meridian through its position and the fore-and-aft line (of 

the ship), expressed in angular units from true north (000º). 

TC Type Certificate (air) 

TCA The Coastguard Agency (UK) 

Merged with MSA in April 1998 to become MCA. 

TCA time of closest approach 

Time that a satellite is closest to a beacon or rx during a pass. 

TCAA Transalatic Common Aviation Area 

TCAR three-carrier ambiguity resolution 

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March 2012

TCAS Traffic-alert and Collision Avoidance System (=ACAS in Europe) 

TCAS-I generates conflicting traffic advisories (TAs). TCAS-II also 

gives collision avoidance instructions (RAs) in vertical plane. TCAS-II 

with sofware 7.0 mandated from Mar 01. 

TCC Technical Co-operation Ctee (IMO) 

TCC Traffic Control Centre (UK Highways Agency) 

TCG Training Consultation Group (EUROCONTROL) 

TCH threshold crossing height 

TCN Terminal Control North (UK NATS) 

TCN terrain contour navigation 

TCO total cost of ownership 

TCP/IP Transmission Control Protocol/Internet Protocol 

TCPA target closest point of approach 

TCPA time to closest point of approach 

TCS track control system 

TCu towering cumulus cloud 

TCXO temperature compensated/controlled crystal oscillator 

TD time difference 

TDA temporary danger area (ATC) 

TDD time division duplex(ing) (eg GSM phones) 

TDEV time deviation 

TDF two degrees of freedom 

TDM Technology Demonstration Missions (NASA) 

TDMA time-division multiple-access 

TDMS Traffic Demand Management Strategy (UK DTLR) 

TDOA time difference of arrival 

TDOP time dilution of precision 

The factor by which accuracy of receiver clock bias determination is 


TDP touch-down point (landing aircraft) 

TDS Technology Demonstration Systems (Phase of GAGAN - to 2005) 

TDS Technology Development Strategy (US, eg GPS) 

TDWR terminal doppler weather radar 

TEB Tender Evluation Board (ESA) 

TEC total electronic content (typically of ionosphere) 

Integrated value of electronic concentration - delay of GPS signal is 

directly proportional to TEC. 

TECU total electronic content (of ionosphere - measured vertically (UP)) 

TED theoretical escape direction (animal navigation) 

Tele-parking Use of SMS to be remotely charged for parking 

TELEPAY EC project for innovative universal transport payment system (FP5) 

TEM Threat and Error Management (IATA) 

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March 2012

TEM transmission electron microscope 

TEMPO temporarily (met) 

TEN Trans-European (Transport) Networks (EU) 

TERCOM terrain contour matching (navigation technique) 

TERNAV terrain-referenced navigation 

TERPS Terminal Instrument Procedures 

TETRA Trans European Trunked Radio Access 

ETSI standard for mobile radio used by fleets of vehicles such as 

emergency services. Combines functions of digital mobile phones, PMR 

radio systems and mobile data. Uses 410-430 MHz. UK system known 

as Dolphin. TETRA2 is an upgrade. 

TEU twenty-foot equivalent unit (container) 

TF terrain following 

TF track to a fix 

TFE timing and frequency equipment 

TFJS Tactical Field Jamming System (GPS - US) 

TfL Transport for London 

TFM traffic flow management 

TFOM time figure of merit 

TFR temporary flight restriction (US) 

TFR terrain following radar 

TFS time and frequency solution 

TFT thin film transistor 

TFT-LCD thin film transistor liquid crystal display 

Tgd estimated group delay differential 

TGI Tide Gauge Inspectorate (UK Tide Gauge Network) 

TGL Temporary Guidance Leaflet (JAA) 

TGRS Translated GPS Range System 

TH Trinity House (Corporation of Trinity House, London) 

Covers England, Wales, Channel Islands and Gibraltar. 

TH true heading 


defined by the angle between the meridian through its position and the 

fore-and-aft line (of the ship), expressed in angular units from true 

north (000º). 

TH-UWB time-hopping UWB 

THD transmitting heading device 

Thermosphere Part of atmosphere from ~ 85-120 km 

THLS Trinity House Lighthouse Service (Corporation of Trinity House) 

Covers England, Wales, Channel Islands and Gibraltar. 

THUCC Trinity House User Consultative Committee 

THUM relative humidity 

TIA US Telecomms Standards Institute (equiv of Europe’s ETSI) 

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March 2012

TIBA Traffic Information Broadcast for Aircraft 

TICTOC Timing over IP Connection and Transfer of Clock 

TID travelling ionospheric disturbance 

TIDE Technology Initiatives for Disabled and Elderly People (EU) 

TIE time interval error 

TIFF Tagged Image File Format 

Standard for digital image compression; includes JPEG. 

TIGER Topologically Integrated Geocoding and Referencing (US data f’mat) 

TIGER Traffic Information and Guidance on European Roads (EU DRIVE 2) 

TIGNS tightly-coupled (closed loop) IMU/GPS navigation system 

TIH Traffic Information Highway (carries data from TCCs) 

TIS traffic information service (air) 

TIS-B traffic information services - broadcast 

TISPOL European Traffic Police Association 

TL transition level 

TL until (met) 

TLM telemetry 

TLS target level of safety 

TLS total least squares 

EG for RVSM TLS = 2.5x10 -9 fatal accidents per aircraft flight hour as 

a consequence of altimetry errors. 

TLS Transponder Landing System 

TLZ time-limited zone (air) 

TM telemetry 

TMA terminal manoeuvring area (ATC) 

TMA Threat Model A (eg for GNSS signals) 

Digital errors where denoting lead or lag of the chip transition. 

TMA Traffic Management Advisor (ATC automation tool)(US) 

TMAS telemedical assistance service 

TMB Threat Model B (eg for GNSS signals) 

Analog errors through damped natural frequency and damping factor 

of second order filter. 

TMC Threat Model C (eg for GNSS signals) 

A combination of digital and analog errors i(TMA and TMB). 

TMC Traffic Message Channel 


TMC Forum EC forum to coordinate TMC activities (62 industry members in 

TMG track made good (true track between 2 fixes) 

TMHD transmitting magnetic heading device (maritime) 

TMS Testbed Master Station (GRAS) 

TMS TOA measurement system 

TMZ transponder mandatory zone (air) 

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March 2012

TN true north (northerly direction of the meridian) 

TNAB Telecomms & Navigation Advisory Board 

TNSE total navigation system error 

TOA time of arrival 

In cellphone location could give accuracy of 125 m. 

TOC time of coincidence (eg LORAN-C timing) 

TOC time of computation 

TOC top of climb 

TOCI time of coincidence interval (eg LORAN-C timing) 

TOD time of day 

TOD top of descent 

TOE time of emission 

TOGA take-off and go-around (mode of autopilot) 

TOID Topographic Identifier (polygon features in OS MasterMap) 

Unique 16-digit reference for data above and below ground. 

TOPS Total Operations Processing System (for train movements) 

TORA take off run available 

TORMES System for visually impared in cities (uses EGNOS & SISNeT)(Spain) 

TORT Generic legal term relating to breach of duty and liability. 

TOT time of transmission 

TOTS Tanker Officers Training Standards (marine) 

TOW time-of-week 

Least 19 significant bits of GPS Z-Count giving time through the week 

in 1.5-second units. Truncated version in 6-second epochs included in 

navigation message HOW. 

TP Thematic Priority (EU FP6) 

TPA taxi position awareness (for aircraft) 

TPA technical partner agreement 

TPAS Traffic Proximity Alert System (air) 

TPAT (C-TPAT) Trade Partnership Against Terrorism (US) 

TPEG Traffic Protocol Experts Group 

A protocol for relaying traffic information. Used by DAB for invehicle 

systems. 

TPO tree preservation order 

TPS transmission parameter signalling 

TPWS Train Protection and Warning System 

TQM total quality management 

TRA temporary restricted area (ATC) 

Trackstar System for tracking stolen vehicles (RAC) 

TRACON Terminal Radar Approach Control 

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March 2012

Trafficmaster System that collects road traffic flows and disseminates them (UK) 

Covers all UK major motorways and most A roads. Expanded into 

continental Europe from 2001. 

TRAN Committee on Transport and Tourism (European Parliament) 

TRAN Terrestrial Regional Augmentation Network (EGNOS) 

Transit discarded US navigation satellite system 

TRANSSC Transport Safety Standards Committee (IAEA) 

TRB Test Review Board (EGNOS) 

TRB Transportation Research Board 

TREN (Directorate General) TRansport and ENergy (EC - now MOVE) 

TRIDENT EC project on data sharing for public transport information systems 

trk track 

trkg tracking 

TRL Transport Research Laboratory (UK) 

TRN terrain-referenced navigation 

TROPIC Traffic Optimisation by the Integration of Information & Control 

TRP Technology Research Programme (ESA) 

TRS Terrestrial Reference System 

TRS Testbed Reference Station (GRAS) 

TRSB time-referenced scanning beam 

TRUCE Training for Unusual Circumstances and Emergencies (CAA) 

true position The error-free latitude and longitude (2D) and height (3D) coordinates 

in a specified geodetic datum (IMO). 

TS thunderstorm (met) 

TS Tracking Station (GPS) 

TSA target speed across track 

TSA Transport Security Administration (US) 

TSAS Terminal Surveillance & Approach System (air) 

TSB Technology Strategy Board (UK) 

TSCPTS Traffic Signal Controller Performance Test System (UK DTLR) 

TSCU touch screen control unit 

TSD traffic situation display (ADS-B) 

TSE total system error (also TNSE = total navigation system error) 

TSG timing signal generator 

Tsikada Original Russian GNSS, replaced by GLONASS 

TSL target speed along track 

TSL total signal loss (eg of GPS) 

TSL/RD total signal loss / route duration (% of route time that signal lost) 

TSO Technical Standard Order (US - air) 

TSO Technical Standard Order (US FAA or JAA as JTSO) 

TSO C-129a covers certified avionics receivers. 

TSPI time, space and position information 

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March 2012

TSS traffic separation scheme 

Tsunami Wave generated by seismic activity, seismic sea wave 

TT true track (actual path of (ship’s) movement relative to the earth) 

TT&C telemetry, tracking and command(ing) 

TTA time to alarm/alert 

The time elapsed between the occurrence of a failure in a system and 

its presentation to the user (after IMO). Maximum allowable time 

between the appeaance of an error outside the protection limit at the 

integrity monitor and the broadcast of the alarm (USCG). 

TTC Telemetry & Telecommand Station (Galileo) 

TTC telemetry, tracking & command/control 

TTEC Transport Technology Ergonomics Centre (Loughborough University) 

TTF time to fix 

TTFF time to first fix 

TTFU time to first use 

TTG time to go 

TTI Tourist and Traveller Information 

TTPO Technology Transfer Programme Office (ESA) 

TTS Tactical Tool Suite (GPS) 

TTS Transport Telematic System 

TUEM ATCOs’ union in EUROCONTROL 

TUNE time component of the user navigation error 

TVAC thermal-vacuum (testing, eg of satellite) 

TVE total vertical error 

TVOR terminal VOR (low-powered as an approach aid) 

TWD true wind direction 

TWDL two-way data link 

TWG Transport Council Working Group (EU) 

TWP Technical Work Programme (ICAO) 

TWR tower (air traffic control tower) 

TWS true wind speed 

TWSTFT two-way satellite and time frequency transfer 

TWTA traveling wave tube amplifier 

Tx transmitter 

TXC TransXChange 

An XML schema for exchange of bus route & schedule data. 

TXCO temperature-controlled crystal oscillator 

TYRO beginner or novice (used in ATC in emergency situations) 

U-TDOA Uplink-TDOA (to calc cellular phone positions from base stations) 

UA unmanned aircraft 

UAC Upper Air Control (Centre) 

UACC Upper Air Control Centre 

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March 2012

UAIM user autonomous integrity monitoring 

UAIS Universal Automatic Identification System (IMO MSC 74(69) Anx C) 

UAR upper air route 

UART universal asynchronous receiver-transmitter 

UAS unmanned aircraft system 

UAS upper airspace service 

UASRA upper airspace special rules area 

UAT universal access transceiver 

UAV uninhabited/unmanned aerial vehicle 

UB unlit buoy 

UBS universal bulk ship 

UCAV unmanned combat air vehicle 

UCLASS Unmanned Carrier-Launched Airborne Surveillance and Strike (UAV) 

UDA upper advisory area 

UDF UHF direction finding 

UDMS Urban Data Management Society 

UDP User Datagram Protocol (Internet) 

UDR upper advisory route (ATC) 

UDRE user differential range error (eg in WAAS/EGNOS) 

UE user equipment 

UERE (or URE) user equivalent range error 

Any error contributing to the error budget of a atand-alone satnav rx, 

expressed as an equivalent error in the range between the user’s rx 

and satellite. Total UERE is the rss of the individual errors. 

UGV unmanned ground vehicle 

UHF ultra high frequency (300-3,000 MHz) 

UIC Union Internationale des Chemins de Fer (based in Paris) 

International Union of Railways. 

UID user interface document 

UIG Urban ITS Group (UK DTLR) 

UIR Upper Information Region (FIR above FL245) 

UIRE user ionospheric range error 

UITP Union Internationale de Transport Public 

UK SSC Cabinet Office Spectrum Strategy Committee (UK) 

UKAB United Kingdom Airprox Board 

UKCIP UK Climate Impacts Programme 

UKF unscented Kalman filter 

UKHO United Kingdom Hydrographic Office 

UKISC United Kingdom Industrial Space Committee 

Sponsored by SBAC and INTELLECT. 

UKLFHB UK Low Flying Handbook (military) 

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March 2012

UKMF UK Maritime Forum 

Informal forum of ICS, IMarE, NI, RIN, RINA, and SUT. 

UKMO UK Meterological Office 

UKMPA UK Maritime Pilots’ Association 

UKOOA UK Offshore Operators Association 

UKSAR United Kingdom Search & Rescue Committee 

UKSCC United Kingdom Satnav Co-ordination Committee 

UKSON UK Safety of Navigation (MCA Ctee) 

ULB underwater location beacon (eg for blackboxes) 

ULBC ultra large bulk carrier 

ULCC ultra large crude carrier 

ULCC ultra large crude carrier 

ULI Research & Development Council for Land (Swedish AGI) 

ULS Up-Link Station (Galileo) 

UML Unified Modelling Language 

UMRP user minimum received power 

UMS Universal Measurement System (shipping) 

UMTS Universal Mobile Telecommunications Service (3G) 

3rd generation mobile phone standard (2002+) combining speech and 

internet (IP). Works up to 2 Mbps. Internationally known as 

IMT 2000. 

UN United Nations 

UNCLOS United Nations Convention on the Law of the Sea 

UNE user navigation error (may be horizontal UHNE or vertical UVNE) 

Broadly equal to the constellation ranging error x DOP. 

UNIGRACE Unification of Gravity Systems in Central and Eastern Europe 

UNISIG Railway signalling & comms industry consortium 

UNIX A computer operating system (AT&T) 

UNOOSA United Nations Office for Outer Space Affairs 

UNTOC un-TOC second offset (LORAN-C) 

UPRN Unique Property Reference Number (UK OS & Post Office) 

UPS uninterrupted power supply 

UQ ultra-quick flashing light 

URA user range accuracy 

Prediction of max UERE (minus ionospheric error) broadcast in each 

GPS satellite’s navigation message. 

Uragan Name given to GLONASS satellites 

URAV unmanned reconnaissance air vehicle 

URE user range error (GPS)(see UERE) 

Range error along path between sat and rx that user will experience. 

URL Uniform Resource Locator (Internet address) 

URSI Union radio-scientifique internationale 

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March 2012

US user segment 

USB Universal Serial Bus (computer connection at 12 Mbps - intro Jun 98) 

USC United States Code 

USCA ATCOs’ union in Spain 

USCAHC US/Canada Hydrographic Commission 

USCG United States Coast Guard 

USGIC US GPS Industry Council 

USGS US Geological Survey 

USL Uniform Shipping Laws 

USNO US Naval Observatory 

USPA user-specific performance analysis 

USSPACECOM US Space Command 

UT Universal Time 

UT unscented transformation (using Kalman filter) 

UT user terminal 

UT0 Uncorrected Universal Time 

UT1 UT0 corrected for polar variation 

The mean solar time of the prime meridian obtained from direct 

astronomical observation and corrected for the effects of small 

movements of the earth relative to the axis of rotation (polar 

variation). 

UT2 UT0 corrected for polar & seasonal variations 

UTC Co-ordinated Universal Time 

Corresponds exactly with TAI but differs from it by an integral 

number of seconds - positive or negative leap seconds - to ensure that 

the departure of UTC from UT1 never exceeds ±0.9 secs. GPS time 

differed by 13 leap seconds in Oct 2000, otherwise always within 

100ns. 

UTC Universal Time Control (Galileo) 

UTC urban traffic control 

UTD user terminal demonstator (eg Galileo) 

UTM Universal Transverse Mercator (using a meridian as line of contact) 

UTM Unusable Time (see also EUTM and AUTM) 

When a NELS Loran-C transmitter does not transmit signals or when 

signal is out of tolerance. 

UTMC Urban Traffic Management and Control (DTLR 5-year R&D prog) 

UTP unshielded twisted pair (of wires carrying data) 

UTP user terminal prototype (eg STENAV) 

UUV unmanned underwater vehicle 

UWB ultra-wide band (transmission - typically of GHz over short range ) 

V&V verification and validation 

V2I (also V2X) vehicle-to-infrastructure (part of CVIS) 

V2V vehicle-to-vehicle comms (part of CVIS) 

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March 2012

V2X (also V2I) vehicle-to-infrastructure (part of CVIS) 

VA volcanic ash (met) 

VAAC Volcanic Ash Advisory Centre 

Provides reports and forecasts of volcanic ash plumes. 

VADR voice and data recorder (aircraft) 

VAFORIT Very Advanced Flight Data Processing OR Implementation System 

German DFS contract. 

VAL vertical alert limit/level (eg for WAAS precision approach etc) 

VAMS Virtual Airspace Modeling and Simulation (NASA/Boeing ATC 

VANESSA Validation and ANalysis of EGNOS Signal within Swiss Airspace 

Var variation 

Angle between TN and MN, from TN eastwards named E (+), 

westwards named W (-). 

VAS value-added service 

VASIS Visual Approach Slope Indicator System 

VASP value-added service provider 

VBA vibrating beam accelerometer (for MEMS IMU) 

VBM Variable Butler Matrix (phase-shifters and amps, eg for jamming sim) 

VBS virtual base station 

VC in vacinity (met) 

VCA Vehicle Certification Agency (for EMC of vehicles) 

VCASS Visualisation-based Collision Avoidance Support System 

VCR visual control room (ATC) 

VCS voice communications system (ATC) 

VDB VHF data broadcast 

VDF VHF direction finding 

VDL VHF Digital Link (ARINC) 

Civil air data link for air-to-ground business and ATS messages. VDL-2 

in service in 2001. VDL-3 (TDMA) by about 2007. VDL-4 is latest 

proposal at 19,200 baud. 

VDOP vertical dilution of precision 

The factor by which the one-dimensional vertical accuracy of a fix is 


VDP visual descent point 

VDR voyage data recorder 

vertical circle Great circle of the celestial sphere throught the zenith & nadir 

VEX Vertical Expansion (programme - eg coverage of 8.33 kHz channels) 

VFR visit friends or relatives’ - category of air travel 

VFR visual flight rules 

VGA Standard display format of 640 x 480 pixels 

VGS VHF ground station 

VGS visual guidance system 

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VHDL VHSIC Hardware Description Language 

VHF very high frequency (30-300 MHz) (metric waves) 

VHO very high orbit (perigee & apogee above GEO of 36,000 km) 

VHR very high risk (marine) 

VHSIC very high speed integrated circuit 

VIC Virtual Identity Card 

VICS Vehicle Information and Communications System (Japan) 

ViewNet Next generation distributed mapping system (UK TSB) 

VIKING 1995 project to develop and coordinate traffic management & 

telematics schemes (Denmark, Finland, Norway, Sweden, N Germany. 

VIMSAS Voluntary IMO Member State Audit Scheme 

VIN vehicle identification number 

VIPS Vessel Identification and Positioning System (US) 

VIS visual interactive simulation 

VISTA Visualising Integrated Information on Buried Assets 

3-D mapping project to integrate disparate records of buried 

pipes, cables, ducts and wires. 

VITA vision technology application 

Viterbi Dynamic programming algorithm for finding the most likely sequence of 

hidden states – called the Viterbi path. 

VLA very light aircraft (EASA) 

Single engine (not jet); 1 or 2 seats; MTOW not >750 kg; stall speed 

not >83 km/h (45 knots). No aerobatics and daylight VFR only. 

VLBC very large bulk carrier 

VLBI very long baseline interferometry 

VLCC very large crude carrier 

VLE virtual learning environment (teaching via the web and e-mail) 

VLF very low frequency (3-30 kHz) 

VLJ very light jet (

Volpe John A Volpe National Transportation Systems Center (US) 

Produced the report ‘Vulnerability Assessment of the Transportation 

Infrastructure Relying on the GPS’, dated 29 Aug 01. 

VOR VHF Omnidirectional Range 

VORTAC collocated VOR and TACAN 

VOSL value of statistical life 

VPL vertical protection limit (WAAS) 

Used by VAL in precision approach. 

VPL HO 

fault-free vertical protection limit 

VPN virtual private network 

VPP variable pitch propeller 

VPS Vehicle Positioning Systems (=MPS)(term used in Hong Kong) 

VR virtual reality 

VRD virtual retinal display 

Data projected onto lightweight spectacles. 

VRM variable range marker 

VRML Virtual Reality Model Language 

VRP vehicle routing problem 

VRP vessel response plan 

VRP visual reporting point (air) 

VRS virtual reference station (technique for RTK) 

VRSS virtual reality ship simulator 

VS vertical speed 

VSAT very small aperture terminal (eg ship comms) 

VSI vertical speed indicator 

VSWR voltage standing wave ratio 

VTE vessel technical error 

VTEC vertical total electron content (of ionosphere) 

VTIS vessel traffic information system 

VTM vessel traffic management 

VTMD Vessel Traffic Monitoring Directive (EC Directive 2002/59/EC) 

VTMIS vessel traffic management and information services 

VTMIS-NET VTMIS Network (EC DG VII) 

VTMS vessel traffic management service 

vTRC Virtual Transport Research Centre (ESRC) 

VTS vehicle traffic system 

VTS vessel traffic service/system 

VTSO vessel traffic service operator 

VTSS vessel traffic separation scheme 

VTUAS vertical take-off unmanned air system 

VUNE vertical component of the user navigation error 

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W watt 

W-CDMA Wideband CDMA (air interface standard in 3G mobile comms) 

W-CDMA wideband code division multiple access 

W-Code GPS encryption code to add to P-Code to create Y-Code 

W/V wind velocity 

W3C World Wide Web Consortium 

WAAS Wide-Area Augmentation System 

FAA term describing their GNSS-1, augmenting GPS SPS from a 

geostationary satellite with additional navigation information plus 

differential and integrity data. Available for VFR Aug 01, IFR Aug 03 

WAC World Aeronautical Chart (1:1 million scale) 

WACAF Western and Central African Office (ICAO) 

WACS wireless airport communication system 

WAD wide-area differential 

WADGPS wide area DGPS 

WAFC World Area Forecast Centre (London [Exeter 2004] and Washington) 

WAFS World Area Forecast System (ICAO) 

WAGE Wide Area GPS Enhancement 

WAH when able higher (ATC) 

WAM wide-area multi-lateration 

WAN wide area network (often joining together LANs) 

WAP wireless application protocol (rhymes with ‘zap’) 

Specification to enable mobile phone, pager or PDA to access the 

Internet. 

WARC World Administrative Radio Conference (now WRC) 

Wb weber (magnetic flux) 

WBMOD Wide-band Scintillation Model (for GPS) 

WCS Web Coverage Service (of OpenGIS Spec) 

WCV waypoint closure velocity 

WDOP weighted dilution of precision (see DOP) 

WEEE Waste from Electrical and Electronic Equipment (EC Directive) 

WEND Worldwide Electronic Navigational Chart Database (IHO) 

WEP Wired Equivalent Privacy (WiFi security) 

WERD Western European Road Directors 

WETREP Western European Tanker Reporting System (from July 2005?) 

WFS Web Feature Service (of OpenGIS Spec) 

WG-GGI Working Group on Geodesy and Geographic Information 

WGS World Geodetic System 

A consistent set of parameters describing the size and shape of the 

earth. Most common system is WGS-84 (1984), used by GPS; uses 

semi-major axis of 6,378,137 m and flattening of 1/298.257. 

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white-box testing Testing that uses knowledge of internal workings and structure 

See black-box testing. 

Wi-Fi Alliance Global non-profit organisation based in US 

WiFi (Wi-Fi) A name for the 802.11 wireless interconnection standard 

Operate in 2.4 and 5 GHz bands. 

WIG wing-in-ground craft 

WiMAX WiFi system with range of 4-6 miles, extendable to 30 miles 

WIMP windows, icons, mouse, pointer (describes windows style displays) 

WIP work in progress 

WIPP WAAS Integrity Performance Panel (US) 

WL water line 

WLAN wireless local area network 

WLBGA wafer-level ball-grid array (package format of chip, eg GPS rx) 

WLS weighted least-squares 

WMI World Maritime Institute 

WML Wireless Markup Language (simplified HTML/XML for WAP etc) 

WMO World Meteorological Organisation 

WMS Web Map(ping) Service (of OpenGIS Spec) 

WMS Wide Area Master Station (WAAS) 

WMS Wireless Maritime Services 

WMTS web map tile service 

WMU World Maritime University 

WN wavelet network (for modeling and predicting data) 

WN week number 

WNT WAAS Network Time 

WNTI World Nuclear Transport Institute 

Formed 1998, based in London, 45 member states in 2008. Dedicated 

to the safe, efficient and reliable transport of radioactive materials. 

WOW weight on wheels 

WPA WiFi Protected Access (WiFi security) 

WpB bearing of a waypoint 

WpD distance to waypoint 

WPM white phase modulation 

WPS WiFi Positioning System 

WPT waypoint 

WRC World Radio Conference (of the ITU) eg WRC-2000 

WRDA weapons range danger area 

WRO1024 GPS week roll-over 

WRS Wide Area Reference Station (WAAS) 

WS&T Weapon Systems and Technology 

WSDL Web Service Description Language (for OpenGIS) 

WSN Wide Space Network (comms links between satellites) 

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WSO Weapons Systems Officer 

WSSE weighted sum of squared errors 

WT water track (path of ship’s movement through the water) 

WT watertight 

WTA Wireless Telegraphy Act (UK) 

WTEMP water temperature 

WUL worst user location (integrity chack) 

WV water vapour 

WWAN wireless wide area network 

WWNWS World-Wide Navigational Warning Service (IMO & IHO) 

WWRNS World-wide Radionavigation System 

Described in IMO Res. A.815(19). 

www World-wide Web (Internet) 

Wx weather 

WX NIL no significant weather 

WYSIWYG what you see is what you get 

X-112 extended emergency phone call giving data alongside voice call 

X-band Old radar band 8-12 GHz (ITU assigned 8,500-10,680 MHz) ~ 3 cm 

XAL HAL or VAL 

XGA Standard display format of 1,024 x 768 pixels 

XLRP XML location reporting protocol 

XML Extensible Mark-up Language (complements HTML) 

XTD cross-track distance (perpendicular to ground track) 

XTE cross-track error (perpendicular to ground track) 

Y-Code (P(Y)) encrypted P-Code (comprises modulo-2 addition of P-Code & W-Code) 

Y2K Year 2000 

Y2Y year-to-year 

YAH You are here (maps for pedestrians) 

Z zenith (point on the celestial sphere vertically overhead) 

Z-Count Fundamental GPS time unit 

A 29-bit binary number of which 10 most significant bits give GPS 

week number and 19 least significant give time-of-week (TOW) count in 

units of 1.5 seconds. Truncated TOW in 6-sec epochs included in 

navigation message HOW. 

ZD zone description 

ZigBee standards-based wireless networking system 

ZLG Zero-Lock Laser Gyro (2 laser gyros in one - Northrop Grumman) 

ZT zone time 

The local mean time of a reference or zone meridian, whose time is 

kept throughout a designated zone. The zone meridian is usually the 

nearest meridian whose longitude is exactly divisible by 15 º. 

ZTD zenith tropospheric delay 

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ZUPT zero velocity update (of in-vehicle navigation system) 

ZVU zero velocity update 

ZZKRL ATCOs’ union in Poland 

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navigation acronyms, abbreviations and definitions - International ...

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