ESA - Galileo rubidium clocks – a year of in-orbit experience
Europe’s first satellite-borne rubidium clocks have been in orbit for over a year. There is good news for the building of the Galileo system: the results obtained from GIOVE-A’s first year of operations show performance that is largely in line with the specifications.
European Commission Mission Segment International Laser Ranging Service Orbit Determination Time Synchronisation Rubidium Clock
Source: esa.int