On Friday 16 March, a ferry will set sail from the port of Piraeus, bound
for the Greek island of Santorini with some special passengers and
navigation equipment on board.

The equipment consists of a receiver to pick up the signal broadcast by
Europe’s fledgling EGNOS satellite navigation system and the passengers
include officials from the Greek Navy, Greek shipping, national
telecommunications agencies, the European Commission and the European
Space Agency.

The purpose of the voyage is to demonstrate how the accuracy and eventual
integrity of the EGNOS signal could improve navigation in the difficult
Greek archipelago. EGNOS should make it possible to navigate accurately
within the confined channels and to identify harbour entrances to within
a few metres without other navigation aids.

The demonstration is one of several events illustrating how EGNOS is
developing as a new navigation service. During early 2000, the system was
used to guide a large ship to its berth in the harbour at Genoa, Italy.
On another occasion, last November, a Fiat car, driven around a track in
Turin, Italy, showed that EGNOS has the potential to determine position
to within a metre. Several flight demonstrations have also shown that the
improved accuracy and integrity of the EGNOS signal could lead to much
more effective use of airspace.

EGNOS, which stands for European Geostationary Navigation Overlay Service,
is being developed by ESA in conjunction with the European Commission and
Eurocontrol, the European Organisation for Safety of Air Navigation. It
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 critical
applications, such as flying aircraft and navigating ships through narrow
channels. It is due to become operational in early 2004.

EGNOS receives signals from the GPS and GLONASS satellites and, using
specialised hardware, adds a correction factor which makes them accurate
to five metres or better. The signals are then beamed back into space, and
broadcast by the EGNOS transponders onboard Inmarsat satellites and picked
up by receiving equipment, fitted into vehicles. When EGNOS is fully
operational, it will have three satellites.

This week’s test in Greece will be the first since additional ranging
stations became available in the Mediterranean area, thanks to a
co-operation with the Italian tests bed developments. It will monitor
the improvement brought about by the extra ranging stations and also
test the system near the edge of its geographical area of operation.

EGNOS shows not only greater accuracy but also greater consistency and
reliability than GPS alone. The fully operational system will be capable
of alerting users within less than six seconds of a malfunction of the
GPS or GLONASS satellite constellations.

EGNOS is a first step towards Galileo, a fully-comprehensive European
global satellite navigation system. Consisting of 30 satellites in medium
Earth orbit, Galileo will be under civilian control and will provide a
reliable, accurate and guaranteed satellite navigation service from
2006/8 onwards.

Related News

* What is EGNOS?


* Road test for EGNOS, Europe’s new satellite navigation system


* EGNOS Test Bed joins forces with the Mediterranean Test Bed


Related Links



* EGNOS video


* Galileo website (European Commission)



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[Image 2:
EGNOS architecture