Patent ID: 7920650

Claim:
A system for characterizing stability of a satellite clock in a satellite having a transmitting device that is configured to emit a transmission signal at a transmission frequency that is a function of a state of the satellite clock; the system comprising: a receiver clock which has a precision greater than precision of the satellite clock; a receiving device which is configured to receive the transmission signal, determine a received signal therefrom, and determine from the received signal at least one of a received signal frequency and a received signal phase by using the receiver clock; and an evaluation device which is configured to determine at least one of a frequency offset, a frequency drift and an Allan deviation of the transmission frequency from at least one of the received signal frequency and/or the received signal phase, and to determine one of the stability of the satellite clock and validity of the time indication of the satellite clock, based on at least one of the determined offset, the determined drift and the determined Allan deviation, thereby characterizing the satellite clock.