European GPS Overlay Ready for Operations

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PARIS — Europe’s regional system offering verification and enhancement of GPS timing and navigation satellite signals was declared ready for use Oct. 1 for its freely accessible service, with higher-reliability versions scheduled to be added in 2010.

The European GPS Navigation Overlay Service, Egnos, uses navigation terminals on two Inmarsat satellites and the European Space Agency’s Artemis spacecraft — all in geostationary orbit — to augment GPS performance. Similar regional systems have been built in the United States and in Japan.

The European Commission, which has taken charge of Egnos deployment and views it as a precursor for Europe’s GPS equivalent, called Galileo, expects that Egnos’ safety-of-life service will be ready for use in 2010. It too will be available free of charge.

An Egnos Commercial Service, now being tested, is slated for deployment in 2010 but it remains unclear what the terms of use will be. A Toulouse, France-based consortium of seven European air-navigation agencies, called ESSP, is under contract to manage Egnos at least until 2013. European governments have spent some 350 million euros ($514.3 million) developing and validating the Egnos system. The ground infrastructure includes 34 ranging and integrity-monitoring stations to receive satellite signals; four control and processing centers to validate satellite-signal integrity and send correction messages; and six stations that receive corrected data and upload it to the geostationary satellites for later dissemination as a GPS-type navigation signal.