N° 14–2000: A step forward in European satellite navigation systems

The GNSS programme is being carried out in two stages: GNSS-1, the first generation system, based on signals received by the existing American GPS and Russian Glonass constellations, and GNSS-2 , the second generation, that will provide improved navigation and positioning services to civil users. Galileo will be Europe's contribution to GNSS-2.

Within GNSS-1, Europe is contributing EGNOS, the European Geostationary Navigation Overlay System, aimed at augmenting the performance of GPS and Glonass in terms of precision and data integrity. EGNOS is now becoming a reality as a test bed - a simplified version of the fully fledged system has recently been readied by Alcatel Space, the prime contractor leading the international industrial team which is developing the system .

The system is based on use of ground infrastructure and three geostationary satellites (Inmarsat 3 Indian Ocean Region (IOR) and Atlantic Ocean Region East (IOR-E), and, in future, ESA's Artemis telecommunications satellite). These spacecraft are equipped with dedicated navigation transponders to augment the positioning services currently offered by the GPS and Glonass constellations. The EGNOS ground infrastructure will be deployed over more than 40 sites, mostly in Europe. The ground infrastructure for the pre-operational version has already been deployed at many sites around Europe: France, Iceland, Italy, the Netherlands, Norway, Spain, Turkey, United Kingdom and at two sites outside Europe: Kourou (French Guiana) and Hartebeeshoek (South Africa).

The EGNOS system will be qualified at the end of 2003 and will provide in Europe an operational satellite navigation service which will later be improved with the operational introduction of Galileo (in 2008). Similar systems, namely the Wide Area Augmentation System (WAAS) and the MTSAT Satellite based Augmentation System (MSAS) are being developed by the USA and Japan respectively. EGNOS, WAAS and MSAS will be fully interoperable.

Thanks to this test bed system, an EGNOS-like signal has since mid-February been transmitted from space, providing users with a GPS augmentation signal and enabling them to compute their positions to an accuracy of a few metres. The EGNOS test bed signal is currently available in the coverage area of the AOR-E satellite and as of May it will be available in the coverage area of the IOR spacecraft.

This pre-operational version of EGNOS will allow Europe to support demonstration of the operational benefits of GNSS to user communities. The test bed will be used for all modes of transport (air, land and maritime) that require positioning services to accuracies of a few metres, and more particularly safety-critical services. For aviation users, for instance, EGNOS will provide for en-route navigation as well as non-precision approach and precision approach phases of flight.

Furthermore, this early EGNOS version is helping to prepare the future operational introduction of EGNOS in Europe and is demonstrating the potential for extending the EGNOS service beyond Europe's borders. It is at the same time paving the way for the future Galileo satellite navigation system.

ESA is responsible for the overall operations of the EGNOS System Test Bed and, in performing this role, is working in close co-operation with the French space agency CNES and the Norwegian Mapping Authority (NMA) which have also made in-kind contributions to development. Development of the EGNOS System Test Bed was managed by Alcatel Space Industry, ESA prime contractor for EGNOS and by the subcontractors GMV (E), Racal (UK), Seatex (N) and Dornier SatellitenSysteme (D).

The European Commission is more specifically responsible for the promotion of applications and user equipment, an activity which will rely largely on the use of the EGNOS System Test Bed. Financial support is also provided by EC for the EGNOS project, in particular for the lease of INMARSAT-3 transponders and implementation of the Artemis navigation payload.

For further information, please contact :

ESA Communication Department

Franco Bonacina, Media Relations

Tel: + 33 (0)1 53 69 71 55

Fax: + 33 (0)1 53 69 76 90

Laurent Gauthier or

Philippe Michel

ESA/ CST- Toulouse

Tel: + 33 (0)5 61 28 28 01

Fax: + 33 (0)5 61 28 28 66

Further information on ESA at http://www.esa.int