New Concept for the On-Board Master Clock Generation Unit for Future Galileo Satellites

摘要

Measurements based on the Galileo experimental sensor stations have confirmed the expectations regarding the stability of the atomic clocks on-board the GIOVE-A and GIOVE-B satellites. These results are very encouraging for the performance of the Master Time Reference (MTR) generated by the Clock Monitoring and Control Unit (CMCU) on-board the future Galileo satellites. This CMCU will host two Passive Hydrogen Masers (PHM) and two Rubidium Atomic Frequency Standards (RAFS), see [10]. Such a redundancy will allow switching of atomic clock when an abnormal behavior of the MTR is observed. This operation will however require the isolation of the satellite from the constellation, which will degrade the system availability performance.