EGNOS European Geostationary Navigation Overlay Service Basic Technical Background

The EGNOS (Europem Geostationary Navigation Overlay System) System is being developed in Europe to provide GPS and GLONASS regional augmentation services to aviation, maritime and land users. EGNOS is a major element of the European Satellite Navigation Programme (ESNP) which is jointly being implemented by the Commission of the European Union (CEU), the European Space Agency (ESA) and EUROCONTROL. EGNOS will provide the fotlowing services: GEO-based GPS-like Ranging signals (R-GEO) to improve the availability and continuity of GPS posilion fix; GNSS Integrity Channel (GIC) to improve the integrity of GPS and GLONASS-based navigation and position determination for safety critical applicattons: and Wide-Area Differential corrections (WAD) to improve accuracy of GPS-SPS and GLONASS EGNOS will also disseminate accurate time to all users in the Geostationary Broadcast Area (GBA), synchronised to UTC. The EGNOS System is being designed to serve the needs of all modes of transport in the European Region, namely: Civil Aviation as sole means of navigation for all phases of flight up to and including Category l landing; maritime and in-land water navigation and docking; and rail and road transport and traffic monitoring systems. The EGNOS System is also being designed to be compatible and interoperable with the other satellite based augmentation systems, namely. WAAS , Canadian WAAS and MSAS (Multi-transport Satellite based Augmentation System), respectively in the USA, Canada and Japan. This paper provides a system perspective of the EGNOS Project including: EGNOS mission and performance objectives: EGNOS architecture; EGNOS programme overview: and interoperability aspects with other SBAS.