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ESA… EGNOS Flies (SATCOM)


The US GPS global satellite navigation system has an accuracy of 5–10 m. Across our continent that accuracy is greatly sharpened to 1-2 m through the European Geostationary Navigation Overlay Service (EGNOS), an operational precursor to Europe’s coming Galileo global satnav system. EGNOS broadcasts augmented information through a trio of geostationary satellites linked to a network of monitoring ground stations. Credits: ESA
[SatNews] The EGNOS Safety-of-Life signal was formally declared available to aviation.

For the first time, space-based navigation signals have become officially usable for the critical task of vertically guiding aircraft during landing approaches. By using three satellites and a 40-strong network of ground stations, the European Geostationary Navigation Overlay System (EGNOS) sharpens the accuracy of GPS satnav signals across Europe. The signals are guaranteed to the extremely high reliability set out by the International Civil Aviation Organisation standard, adapted for Europe by Eurocontrol, the European Organisation for the Safety of Air Navigation. The EGNOS Open Service was launched in October 2009, for navigation applications where the safety of human life is not at stake, such as personal navigation, goods tracking and precision farming.


EGNOS-equipped aircraft cockpit. From 2 March 2011, EGNOS is open for use by aviation for runway approaches. The runway in question has to have a procedure written by an Air Navigation Service Provider and the aircraft be equipped with an EGNOS receiver and be certified for EGNOS operations. Credits: Eurocontrol
In order to use EGNOS for approaches, Air Navigation Service Providers must publish runway procedures and aircraft and operators have to be equipped with certified receivers and be approved for operations. Some 15 years in the making, EGNOS is the result of a tripartite agreement between ESA, the European Commission (EC) and Eurocontrol. As initial EGNOS program manager, ESA designed, qualified and procured the system from a consortium led by Thales Alenia Space France. Overall program management passed to the EC in 2009. The system’s day-to-day running is overseen by the Toulouse-based European Satellite Service Provider (ESSP). Meeting the aviation industry’s demanding safety requirements, set by Eurocontrol, posed the real challenge for EGNOS’s Safety-of-Life service. ESA produced much of the technical documentation needed for formal safety certification, while Eurocontrol performed independent monitoring of EGNOS performance.

The final system comes with an extremely high degree of integrity built in. The EGNOS signal is guaranteed to maintain a minimum level of accuracy, with just a one in 10 million chance of error. If this reliability falls below this level then EGNOS users are alerted within six seconds. ESA is now acting as the design and procurement agent on behalf of the EC for all major EGNOS system changes throughout its operational lifetime, as well as preparing for the next-generation EGNOS, expected around 2020.