View source for European Geostationary Navigation Overlay Service

{{short description|System that enhances the accuracy of GPS receivers}}
{{Infobox navigation satellite system
|name= EGNOS
|image= [[File:EGNOS logo.svg]]
|type= Augmentation
|status= Operational
|operator= [[European Union Agency for the Space Programme|EUSPA]], [[European Space Agency|ESA]]
|coverage= Europe, North Africa
|cost=€1,1 billion|website=[https://egnos-user-support.essp-sas.eu/ EGNOS]|country=[[European Union]]}}
[[File:EGNOS map.svg|250px|thumb|Map of the EGNOS ground network]]

The '''European Geostationary Navigation Overlay Service''' ('''EGNOS''') is a [[satellite-based augmentation system]] (SBAS) developed by the [[European Space Agency]] and [[Eurocontrol]] on behalf of the [[European Commission]]. Currently, it supplements [[GPS]] by reporting on the reliability and accuracy of their positioning data and sending out corrections. The system will supplement [[Galileo (satellite navigation)|Galileo]] in the future version 3.0.

EGNOS consists of 40 Ranging Integrity Monitoring Stations, 2 Mission Control Centres, 6 Navigation Land Earth Stations, the EGNOS Wide Area Network (EWAN), and 3 [[geostationary satellite]]s.<ref>{{Cite web|url=https://www.gsa.europa.eu/european-gnss/egnos/egnos-system|title = EGNOS System|date = March 2016}}</ref> Ground stations determine the accuracy of the satellite navigation systems data and transfer it to the geostationary satellites; users may freely obtain this data from those satellites using an EGNOS-enabled receiver, or over the Internet. One main use of the system is in [[aviation]].

According to specifications, horizontal position accuracy when using EGNOS-provided corrections should be better than seven metres. In practice, the horizontal position accuracy is at the metre level.

Similar service is provided in North America by the [[Wide Area Augmentation System]] (WAAS), in Russia by the [[System for Differential Corrections and Monitoring]] (SDCM), and in Asia, by Japan's [[Multi-functional Satellite Augmentation System]] (MSAS) and India's [[GPS-aided GEO augmented navigation]] (GAGAN).

[[Galileo (satellite navigation)|Galileo]] and EGNOS received a budget of €14.6 billion for its six-year, 2021–2027, research and development period.<ref>{{Cite web |title=EU Space Programme - Performance - European Commission |url=https://commission.europa.eu/strategy-and-policy/eu-budget/performance-and-reporting/programme-performance-statements/eu-space-programme-performance_en |access-date=2024-06-13 |website=commission.europa.eu |language=en}}</ref>

==History and roadmap==
The system started its initial operations in July 2005, with accuracy better than two metres and availability above 99%.  As of July 2005, EGNOS has been broadcasting a continuous signal, and at the end of July 2005, the system was again used to track cyclists in the [[Tour de France]] road race.<ref>{{cite web|url=http://www.esa.int/Our_Activities/Navigation/The_present_-_EGNOS/What_is_EGNOS|title=What is EGNOS?|date=2 August 2013|publisher=[[ESA]]|access-date=31 January 2016}}</ref>

In 2009, the European Commission announced it had signed a contract with the company [[European Satellite Services Provider]] to run EGNOS. The official start of operations was announced by the European Commission on 1 October 2009.<ref>{{cite web|url=http://www.esa.int/Our_Activities/Navigation/The_present_-_EGNOS/EGNOS_Open_Service_available_a_new_era_for_European_navigation_begins_today|title=EGNOS 'Open Service' available: a new era for European navigation begins today|date=1 October 2009|publisher=[[ESA]]|access-date=31 January 2016}}</ref> The system was certified for use in safety of life applications in March 2011.<ref name="ESA20110302">{{cite web|url=http://www.esa.int/Our_Activities/Navigation/The_present_-_EGNOS/EGNOS_navigation_system_begins_serving_Europe_s_aircraft|title=EGNOS navigation system begins serving Europe's aircraft|date=2 March 2011|publisher=[[ESA]]|access-date=31 January 2016}}</ref>  An EGNOS Data Access Service became available in July 2012.

Initial work to extend EGNOS coverage to the Southern Africa region is being done under a project called ESESA - EGNOS Service Extension to South Africa.<ref>{{cite web|url=http://www.esesa.org/about/index.php|title=What is ESESA?|publisher=ESESA|access-date=31 January 2016}}</ref>

The European Commission is defining the roadmap for the evolution of the EGNOS mission. This roadmap should cope with legacy and new missions:<ref>{{cite web|url=https://gssc.esa.int/navipedia/index.php/EGNOS_Future_and_Evolutions|title=EGNOS Future and Evolutions|date=16 October 2015|publisher=[[ESA]] / NAVIPEDIA|access-date=31 January 2016}}</ref>
* 2011–2030: En-route / NPA / APV1 / LPV200 service based on augmentation of GPS L1 only. The Safety of Life (SoL) will be guaranteed up to 2030 in compliance with ICAO SBAS SARPS.
* 2020+: It is planned that EGNOS will experiment with a major evolution, EGNOS V3, including the fulfilment of the SBAS L1/L5 standard, expansion to dual-frequency, and evolution toward a multi-constellation concept.

In 2021, following [[Brexit]], the United Kingdom withdrew regulatory approval for EGNOS, and aircraft pilots were no longer permitted to use the system.<ref name="RIN">{{cite web | url=https://rin.org.uk/news/572850/Withdrawal-of-EGNOS-for-UK-users.htm | title=Withdrawal of EGNOS for UK users - Royal Institute of Navigation }}</ref>

== Satellites and SISNeT ==
[[Image:SBAS Service Areas.png|thumb|right|Service areas of [[GNSS augmentation|satellite-based augmentation systems]] (SBAS)]]
[[File:Inmarsat-3.gif|thumb|[[Inmarsat]] 3 satellite]]

{| class="wikitable" style="margin: 1em auto 1em auto;"
! Satellite Name & Details
! NMEA / PRN
!Signals
! Location
!Status<ref>{{cite web|url=https://egnos-user-support.essp-sas.eu/new_egnos_ops/?q=egnos_system_realtime|title=REALTIME &#124; Egnos User Support|publisher=ESSP-SAS|access-date=31 January 2016}}</ref>
|-
|[[Inmarsat 3-F2]] (Atlantic Ocean Region-East<ref>{{cite web | url = https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1996-053A | title = Inmarsat 3-F2 | publisher = [[NASA]] | work = NSSDCA Master Catalog }}</ref>)
| NMEA #33 / PRN #120
|L1
| align="center" | 15.5°W
|''retired''
|-
|ARTEMIS <ref>{{cite web | url = https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2001-029A | title = Artemis | publisher = [[NASA]] | work = NSSDCA Master Catalog }}</ref>
| NMEA #37 / PRN #124
| -
| align="center" | 21.5°E
|''retired''
|-
|[[Inmarsat 4-F2]] (Europe Middle East Africa<ref>{{cite web | url = https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2005-044A | title = Inmarsat 4-F2 | publisher = [[NASA]] | work = NSSDCA Master Catalog }}</ref>)
| NMEA #39 / PRN #126
| -
| align="center" | 64°E
|testing
|-
|[[Inmarsat 3-F1]] (Indian Ocean<ref>{{cite web | url = https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1996-020A | title = Inmarsat 3-F1 | publisher = [[NASA]] | work = NSSDCA Master Catalog }}</ref>)
| NMEA #44 / PRN #131
| -
| align="center" | 64.5°E
|''retired''
|-
|[[SES-5]] (a.k.a. Sirius 5 or Astra 4B) <ref name="SES-ASTRA">{{cite web |title=EGNOS Case Study |url=http://www.ses-astra.com/business/en/solutions/government/case-studies/egnos/index.php |url-status=dead |archive-url=https://web.archive.org/web/20090528060009/http://www.ses-astra.com/business/en/solutions/government/case-studies/EGNOS/index.php |archive-date=2009-05-28 |publisher=[[SES (company)|SES]]}}</ref><ref name="beyond">''[[Beyond Frontiers]]'' Broadgate Publications (September 2016) pp97</ref> 
| align="center" | NMEA #49 / PRN #136<ref name=":0">{{Cite web|title = The Almanac| date=21 August 2012 |url = http://gpsworld.com/the-almanac/|access-date = 2015-10-01}}</ref>
|L1 & L5
| align="center" | 5.0°E
|'''active'''
|-
|[[Astra 5B]]<ref name="SES-ASTRA" /><ref name="beyond"/>
| align="center" | NMEA #36 / PRN #123<ref name=":0" />
|L1 & L5
| align="center" | 31.5°E
|'''active'''
|-
|[[Eutelsat 5 West B]]
| PRN #148
|
| align="center" | 5°W
| launched in October 2019, it will use EGNOS 3
|}
Similar to [[WAAS]], EGNOS is mostly designed for [[aviation]] users who enjoy unperturbed reception of direct signals from [[geostationary satellite]]s up to very high [[latitude]]s. The use of EGNOS on the ground, especially in urban areas, is limited due to relatively low [[elevation]] of [[geostationary satellite]]s: about 30° above [[horizon]] in central [[Europe]] and much less in the North of Europe. To address this problem, [[ESA]] released in 2002 SISNeT,<ref>{{cite web|url=http://www.esa.int/Our_Activities/Navigation/Signal-in-Space_through_the_Internet|title=Signal-in-Space through the Internet|date=19 September 2002|publisher=[[ESA]]|access-date=31 January 2016}}</ref><ref>{{cite web|url=http://www.egnos-pro.esa.int/sisnet/publications.html|title=SISNeT - related publications|publisher=[[ESA]]|access-date=31 January 2016}}</ref> an [[Internet]] service designed for continuous delivery of EGNOS signals to ground users. The first experimental SISNeT receiver was created by the [[Finnish Geodetic Institute]].<ref>{{cite web|url=http://www.esa.int/Our_Activities/Navigation/Navigate_via_the_web_with_the_SISNeT_receiver|title=Navigate via the web with the SISNeT receiver|date=6 September 2002|publisher=[[ESA]]|access-date=31 January 2016}}</ref> The commercial SISNeT receivers have been developed by [[Septentrio]]. PRN #136 was placed into the Operational Platform from 23/08/2018 at 10:00 UTC and PRN #120 was placed into Test Platform from 30/08/2018 at 13:00 UTC.<ref>{{cite web|url=http://www.esa.int/Our_Activities/Navigation/The_present_-_EGNOS/Satellite_navigation_receiver_uses_EGNOS_signals_delivered_via_Internet|title=Satellite navigation receiver uses EGNOS signals delivered via Internet|date=25 October 2005|publisher=[[ESA]]|access-date=31 January 2016}}</ref>

== Services ==

* Open Service (OS): It improves positioning accuracy by correcting error sources affecting [[GNSS]] signals intended for a wide range of applications in various domains. The corrections transmitted by EGNOS help mitigate the ranging error sources related to satellite clocks, satellite position and ionospheric effects. EGNOS can also detect distortions affecting the signals transmitted by GNSS and prevent users from tracking unhealthy or misleading signals that could lead to inaccurate positioning. The service is available free-of-charge in [[Europe]] to any user equipped with an appropriate GPS/[[GNSS augmentation|SBAS]] compatible receiver for which no specific receiver certification is required. It has been available since 1 October 2009.<ref>{{Cite web|title=ABOUT OS {{!}} EGNOS User Support|url=https://egnos-user-support.essp-sas.eu/new_egnos_ops/services/about-os|access-date=2020-12-29|website=egnos-user-support.essp-sas.eu}}</ref>
* Safety of Life (SoL) Service: The main objective of the EGNOS SoL service is to support civil aviation operations down to Localizer Performance with Vertical Guidance (LPV) minima. However, the EGNOS SoL service might also be used in a wide range of other application domains (e.g. maritime, rail, road...) in the future. This service provides the most stringent level of signal-in-space performance to all Safety of Life user communities. The EGNOS system has been designed so that the EGNOS Signal-In-Space (SIS) is compliant with the ICAO SARPs for SBAS. It has been available since 2 March 2011.
* EGNOS Data Access Service (EDAS): EDAS is the terrestrial data service and offers ground-based access to EGNOS data in real time and also in a historical FTP archive to authorised users (e.g. added-value application providers). EDAS is the single point of access for the data collected and generated by the EGNOS ground infrastructure distributed over Europe and North Africa, it is aimed at users who require enhanced performance for commercial and professional use. It has been available since 26 July 2012.<ref name="egnos-user-support.essp-sas.eu">{{Cite web|title=About EGNOS {{!}} EGNOS User Support|url=https://egnos-user-support.essp-sas.eu/new_egnos_ops/egnos-system/about-egnos|access-date=2020-12-29|website=egnos-user-support.essp-sas.eu}}</ref>

==Architecture==
[[File:EGNOS RIMS BRN.jpg|200px|thumb|EGNOS RIMS "BRN" (Berlin) close to [[Berlin]]]]

EGNOS is divided into four functional segments:

'''1. Ground segment:''' comprises a network of 40 Ranging Integrity Monitoring Stations (RIMS), 2 Mission Control Centres (MCC), 2 Navigation Land Earth Stations (NLES) per Geostationary Earth Orbit (GEO), and the EGNOS Wide Area Network (EWAN), which provides the communication network for all the components of the ground segment.

* 40 RIMS: the main function of the RIMS is to collect measurements from GPS satellites and to transmit these raw data every second to the Central Processing Facilities (CPF) of each MCC. 
* 2 MCC: these receive the information from the RIMS and generate correction messages to improve satellite signal accuracy and information messages on the status of the satellites (integrity). It acts as the "brain" of the system.
* 6 NLES: the NLESs (two for each GEO for redundancy purposes) transmit the EGNOS message received from the central processing facility to the GEO satellites for broadcasting to users and to ensure the synchronisation with the GPS signal.

'''2. Support segment:''' In addition to the above-mentioned stations/centres, the system has other ground support installations involved in system operations planning and performance assessment, namely the Performance Assessment and Checkout Facility (PACF) and the Application Specific Qualification Facility (ASQF) which are operated by the EGNOS Service Provider (ESSP).

* PACF (Performance Assessment and Check-out Facility): provides support to EGNOS management in the form of performance analysis, troubleshooting, and operational procedures as well upgrading specifications and validations and providing maintenance support.
* ASQF (Application Specific Qualification Facility): provides civil aviation and aeronautical certification authorities with the tools to qualify, validate and certify the different EGNOS applications.

'''3. Space Segment:''' composed of at least three geostationary satellites broadcasting corrections and integrity information for GPS satellites in the L1 frequency band (1575.42&nbsp;MHz). This space segment configuration provides a high level of redundancy over the whole service area in the event of a failure in the geostationary satellite link. EGNOS operations are handled in such a way that, at any point in time, at least two GEOs broadcast an operational signal.

'''4. User Segment''': the EGNOS user segment consists of EGNOS receivers that enable their users to accurately compute their positions with integrity. To receive EGNOS signals, the end user must use an EGNOS-compatible receiver. Currently, EGNOS compatible receivers are available for such market segments as agriculture, aviation, maritime, rail, mapping/surveying, road and location based services (LBS).<ref>{{Cite web|date=2016-03-01|title=EGNOS System|url=https://www.gsa.europa.eu/european-gnss/egnos/egnos-system|access-date=2020-12-29|website=www.gsa.europa.eu|language=en}}</ref><ref name="egnos-user-support.essp-sas.eu"/>

==Aviation==

In March 2011, the EGNOS Safety-of-Life Service was deemed acceptable for use in aviation. This allows pilots throughout Europe to use the EGNOS system as a form of positioning during an approach, and allows pilots to land the aircraft in [[Instrument meteorological conditions|IMC]] using a GPS approach.<ref>{{Cite web|url=http://www.esa.int/Our_Activities/Navigation/The_present_-_EGNOS/What_is_EGNOS|title=What is EGNOS?}}</ref>

As of September 2018 LPV ([[Localizer performance with vertical guidance]]) landing procedures, which are EGNOS-enabled, were available at more than 180 airports across Europe.<ref>{{cite web|url=https://www.esa.int/Applications/Navigation/Precision_EGNOS_satnav_sparking_quiet_revolution_in_aircraft_landings|title=Precision EGNOS satnav sparking quiet revolution in aircraft landings|publisher=[[European Space Agency]]|date=4 September 2018|access-date=3 May 2020}}</ref>
 
{{Clear}}

==References==
{{reflist|2}}

==External links==
{{Div col|colwidth=25em}}
* [https://ec.europa.eu/growth/sectors/space/egnos_en European Commission information on EGNOS]
* [https://www.essp-sas.eu/ Website of the EGNOS operator ESSP SaS]
* [https://egnos-user-support.essp-sas.eu/new_egnos_ops/ EGNOS Operations User Support]
* [https://www.esa.int/Applications/Navigation/EGNOS ESA information on EGNOS]
* [https://www.egnos-pro.esa.int/education/book.html The EGNOS book, ESA Publications, Javier Ventura-Traveset and Didier Flament] {{Webarchive|url=https://web.archive.org/web/20200719041646/http://www.egnos-pro.esa.int/education/book.html |date=2020-07-19 }}
* [https://www.egnos-pro.esa.int/index.html European Space Agency information on EGNOS for Professionals] {{Webarchive|url=https://web.archive.org/web/20200719041656/http://www.egnos-pro.esa.int/index.html |date=2020-07-19 }}
* [http://www.egnos-pro.esa.int/education/index.html Learning EGNOS]
* [http://www.esesa.org/ ESESA - EGNOS Service Extension to South Africa]
* Usman A Zahidi, "EGNOS enabled GPS Software Receiver" Report Page, [https://web.archive.org/web/20161006125256/http://usman.zahidi.dk/publications/EGNOSSoftwareReceiver.pdf ]
* [http://www.environmental-studies.de/Precision_Farming/EGNOS_WAAS__E/3E.html Information on WAAS, EGNOS & MSAS] {{Webarchive|url=https://web.archive.org/web/20210211000151/http://www.environmental-studies.de/Precision_Farming/EGNOS_WAAS__E/3E.html |date=2021-02-11 }}
* [https://gssc.esa.int/navipedia/index.php/Category:EGNOS Navipedia information on EGNOS]—Wiki initiated by the European Space Agency
{{div col end}}

{{Satellite navigation systems}}
{{European Space Agency}}

{{Use British English|date=January 2014}}

[[Category:European Space Agency programmes]]
[[Category:Global Positioning System]]
[[Category:Galileo (satellite navigation)]]
[[Category:Satellite-based augmentation systems]]