European navigation satellite assessed on Greek ferry voyage
On 16 March, a ferry will set sail for the Greek island of Santorini in order to test EGNOS, Europe's fledgling satellite navigation system. EGNOS, which stands for European geostationary navigation overlay service, is being developed by ESA (European Space Agency) in conjunction with the European Commission and Eurocontrol, the European organisation for safety of air navigation. The system improves the accuracy and reliability of navigation signals from the military controlled US GPS and Russian GLONASS global satellite navigation systems to the point where they can be used for safety applications such as flying aircraft and navigating ships through narrow channels. It receives signals from the US and Russian satellite systems and adds a correction factor, making them accurate to five metres or better. The signals are then beamed back into space and broadcast by the EGNOS transponders on board Inmarsat satellites. The signals are picked up by vehicles fitted with receiving equipment. On board the ferry will be officials from the European Commission and the ESA, the Greek Navy, Greek shipping and national telecommunications agencies. They will be accompanying a receiver which will pick up the signal broadcast by EGNOS. EGNOS has already undergone several accuracy tests. In 2000, the system was used to guide a large ship to its berth in Genoa harbour, Italy. The system was also used to drive a car around a track, demonstrating that EGNOS has the potential to determine position to within a metre. Several flight demonstrations have also taken place successfully. The tests in Greek will monitor the effect of extra ranging stations and also test the system near the edge of its geographical area of operation. EGNOS should become fully operational in early 2004 and will have three satellites. EGNOS is a first step towards Galileo, according to ESA. Galileo will be a fully comprehensive European global satellite navigation system consisting of 30 satellites which will be under civilian control and should provide a reliable, accurate and guaranteed satellite navigation service from 2006/8 onwards.