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How does GPS work?

TomTom Education


How GALILEO works

GALILEO will be a constellation of 30 satellites (27 operational, 3 substitutes) divided over three spheres surrounding the Earth at a distance of more than 23,000km. Having 30 satellites not only makes the system extremely accurate, it also means GALILEO can tell users precisely how accurate its signals are, even as they are being sent out - a vital asset in situations where safety is paramount.

The two GALILEO headquarters will be in Toulouse and London, the two control centres in Munchen and Fucine, near Rome. To check received information, 20 sensor stations will connect with the control centres, corrections then being sent back to the satellites via 15 uplink stations.

GALILEO will also have the capability of two-way communication between the satellites and control stations. So that received emergency signals can be forwarded, or the location of the user pinpointed and a message sent to confirm that help is on its way.

1. Satellite navigation users

2. 30 GALILEO satellites

3. Signal position information

4. 20 GALILEO sensor stations

5. Performance data
6. Correction

7. 2 GALILEO Control Centers

8. Corrections & performance data

9. 15 uplink stations

10. Corrections & performance data