Another pair of Galileo navigation satellites is scheduled for launch by a Soyuz rocket this 24 May from Europe’s Spaceport in French Guiana, bringing the Galileo system a step closer to operational use.
GALILEO
European Global Navigation Satellite System
Dear Ladies and Gentlemen,
I am a student from Germany and am currently writing a scientific propaedeutical work about GNSS for School. When explaining the ground-segment I am also referring to the architecture of the GALILEO ground-segment.
After having watched the video above I basically understood everything except the role of the TT&C stations: it is said, that the control stations follow the satellites and give them commands through the TT&C stations (1:19) but unfortunately I don’t understand the necessity of these stations because as far as I understood the tracking is done by the GSS and the commands to the satellites are sent by the Uplink stations…
I would be very thankful for a constructive answer to my problem,
Greeting from Munich,
Anton Wöhler
Dear Anton,
There are 5 TT&C stations distributed around the world, which send/receive TC/TM to/from the satellite.
There are 5 ULS sites with 2 antenna each in charge of up-linking the navigation message.
The GSSs monitor the navigation signals of all satellites on a continuous basis and forward it to the Control Centre where all the processing is done.
Hope this clarifies.