First-hand experience of Galileo
Interview with Galileo expert Paul Verhoef from the policy and infrastructure unit of the European Commission's Directorate-General for Energy and Transport
How does satellite navigation work?
This technology, which has been developed over the last thirty years, for military purposes originally, enables anyone with a receiver capable of picking up signals emitted by a constellation of satellites to instantly determine their position in time and space. The principle is simple: the satellites are fitted with an atomic clock measuring time very accurately - like the one onboard GIOVE-B. They emit specific signals indicating the precise time the signal leaves the satellite. The ground receiver, incorporated for example into a mobile phone, has in its memory the precise details of the orbits of all the satellites in the constellation. By reading the incoming signal, it can thus recognise the particular satellite, determine the time taken by the signal to arrive and calculate the distance from the satellite. Once the ground receiver receives the signals from at least four satellites simultaneously, it can calculate the exact position.
What are the future steps for Galileo?
The next step in the Galileo programme will be the launch as from 2010 of four operational satellites, to validate the main functions of the system and pave the way for the final operation constellation. At this moment, the Commission and the European Space Agency are commencing the procurement of the 26 remaining satellites and associated ground infrastructure. Galileo will be Europe's very own global navigation satellite system, providing a highly accurate, guaranteed global positioning service under civil control. It will be interoperable with the US Global Positioning System (GPS) and Russia's GLONASS.
What's the practical use of Galileo?
Numerous applications are planned for Galileo, providing information concerning the positioning of users and derived value-added services in many sectors such as transport (vehicle location, route searching, speed control, guidance systems), social services (aid for the disabled or elderly), justice system and customs services (location of suspects, border controls), public works (geographical information systems), leisure (direction-finding at sea or in the mountains) or search and rescue systems, telecommunication, etc. It is worth emphasising that the services offered by Galileo will cover the whole planet.