European Geostationary Navigation Overlay Service

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EGNOS logo
Map of the EGNOS ground network (Click to enlarge)

The European Geostationary Navigation Overlay Service (EGNOS) is a satellite based augmentation system (SBAS) developed by the European Space Agency, the European Commission and EUROCONTROL. It supplements the GPS, GLONASS and Galileo systems by reporting on the reliability and accuracy of the positioning data. The official start of operations was announced by the European Commission on 1 October 2009.[1]

According to specifications, horizontal position accuracy should be better than seven metres. In practice, the horizontal position accuracy is at the metre level. The EGNOS system consists of four geostationary satellites and a network of ground stations.

The system started its initial operations in July 2005, with accuracy better than two metres and availability above 99%; it was certified for use in safety of life applications in March 2011.[2] An EGNOS Data Access Service became available in July 2012.

Similar service is provided in North America by the Wide Area Augmentation System (WAAS), and in Asia, notably Japan, by the Multi-functional Satellite Augmentation System (MSAS).

In 2009, the European Commission, owner of the programme, announced it had signed a contract with the company European Satellite Services Provider, to run EGNOS. 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.[3]

Initial work to extend EGNOS coverage to the Southern Africa region is currently being undertaken.[4]

The European Commission is defining the roadmap for the evolution of the EGNOS mission. This roadmap should cope with legacy and new missions:[5]

  • 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 by 2020, EGNOS V3, including the fulfilment of the SBAS L1/L5 standard, expansion to dual-frequency, and evolution toward a multi-constellation concept.

Satellites[edit]

Similar to WAAS, EGNOS is mostly designed for aviation users who enjoy unperturbed reception of direct signals from geostationary satellites up to very high latitudes. The use of EGNOS on the ground, especially in urban areas, is limited due to relatively low elevation of geostationary satellites: about 30° above horizon in central Europe and much less in the North of Europe. To address this problem, ESA released in 2002 SISNeT,[6][7] 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.[8] The commercial SISNeT receivers have been developed by Septentrio.[9]

Satellite Name & Details NMEA / PRN Location
Inmarsat 3-F2 (Atlantic Ocean Region-East) NMEA #33 / PRN #120 15.5°W
ARTEMIS NMEA #37 / PRN #124 21.5°E
Inmarsat 4-F2 (Europe Middle East Africa) NMEA #39 / PRN #126 25°E
Inmarsat 3-F1 (Indian Ocean) NMEA #44 / PRN #131 64.5°E
SES-5 (a.k.a. Sirius 5 or Astra 4B) [1] launched in July 2012 5.0°E
Astra 5B [2] launched in March 2014 31.5°E

Ground stations[edit]

EGNOS RIMS "BRN" (Berlin) close to Berlin

More than 40 ground stations are linked together to create EGNOS network which consists:

  • 34 RIMS (Ranging and Integrity Monitoring Stations): receiving signals from US GPS satellites,
  • 4 MCC (Mission Control Centers): data processing and differential corrections counting,
  • 6 NLES (Navigation Land Earth Stations): accuracy and reliability data sending to three geostationary satellite transponders to allow end-user devices to receive them.

Aviation[edit]

There are plans to develop EGNOS-based landing aids for airliners.[10]

References[edit]

External links[edit]