Characteristics and performance evaluation of Galileo on-orbit satellites atomic clocks during 2014–2017

Abstract The on-orbit characteristics and service performance of Galileo navigation system (Galileo) has been drawn attentions since Galileo is the only one global navigation system which is normally equipped with large-scale, high precision and performance hydrogen atomic clocks. Based on a period of 1000 days’ Galileo satellite clock offset products, this article analyzed the performance changes of Galileo satellite clocks when the working clock is switched to the backup clock. The onboard clock phases, frequencies, frequency drifts, the polynomial fitting residuals and the stabilities have been obtained. Results show that the frequency drifts of Galileo satellite clocks can reach up to a magnitude of 10 −19 and the fitting precisions are superior to 0.3 ns, while the stabilities in the time length of ten thousand seconds can achieve 10 −14 . These mainly can be due to the onboard high performance and precision hydrogen atomic clocks.