Galileo in orbit


The outcome of the first partnership between ESA and the European Commission, the 30-satellite Galileo navigation system will provide high-quality positioning, navigation and timing services to users across the whole world as a civil-controlled service offering guaranteed continuity of coverage.

Galileo’s Development and In-Orbit Validation phase was initiated in late 2003. This phase aims to perform an in-orbit validation of the system using a reduced constellation of four Galileo In-Orbit Validation (IOV) satellites – the minimum number to guarantee the provision of exact positioning and timing at test locations – in combination with Galileo’s terrestrial network of ground stations.

The first two IOV satellites were launched on 21 October 2011, with the next two launched on 12 October 2012. The four satellites perform a dual role, serving as a validation of the overall Galileo system while also being part the operational Galileo constellation – each IOV satellite being designed for a full 12-year lifespan providing navigation services to users worldwide.

IOV assembled and tested by Thales Alenia Space
IOV assembled and tested by Thales Alenia Space

Following launch of the IOV satellites, ESA’s ground station at Redu in Belgium will be employed first for the Launch and Early Phase (LEOP) and then, once the satellites are operational, for the In-Orbit Test (IOT) programme.

This test programme verifies the performance of the navigation payload for the navigation signal: both the downlink (from the satellite, broadcast to users) and the uplink (from Galileo’s Ground Mission Segment, broadcast to the satellites for rebroadcast to users).

The results will be crucial to Galileo’s success, used to set benchmarks for their operational life and used as a reference across the entire Galileo constellation.

Last update: 13 October 2012

Copyright 2000 - 2017 © European Space Agency. All rights reserved.