Worldwide Galileo Ground Segment

Galileo's worldwide ground segment as of March 2013. The sheer scale and reach of Galileo means that its ground segment has a worldwide footprint, as one of the most complex developments ever undertaken by ESA. 

Grey circles - Galileo Control Centres, located in Germany and Italy

Yellow circles - Telemetry, Tracking and Command (TT&C) Stations – the space/ground interface for telemetry acquisition and telecommand uplink to the satellite platforms, as well as two-way ranging

Red circles - Uplink Stations – a network of stations to uplink the corrections to the  satellites for rebroadcast to users as part of the navigation message

Blue circles - Galileo Sensor Stations – spaced across the globe to receive navigation signals from the constellation for rebroadcast to the control centres, enabling continuous clock synchronisation,
signal quality and satellite ranging measurements

Green circles - MEOLUTs,  Medium-Earth Orbit Local User Terminals, not part of Galileo’s navigation  infrastructure but instead used to relay search and rescue messages to local authorities as part of the international Cospas–Sarsat programme

Orange circle - Galileo Security Monitoring Centre

Dark blue circle - Galileo Timing and Geodetic Validation Facility

Brown circle - In-orbit Test Centre.

For more details, see the dedicated article in ESA Bulletin 156