Analysis of medium and short term time-frequency domain performance of GNSS spaceborne atomic clock

A brief introduction to the spaceborne atomic clock was given, and the characteristics of several common spaceborne atomic clocks were analyzed particularly, such as hydrogen clock, cesium clock and rubidium clock. In order to understand the time-frequency performance and actual in-orbit performance of the spaceborne clock better, two different types of the latest spaceborne clock were selected from GNSS system for comparative analysis, and the key performance of their medium and short time frequency was evaluated mainly by using IGS precision clock difference products. The results show that hydrogen clock has the best comprehensive performance, and its frequency stability and daily frequency drift rate average are the best, which changes the previous understanding of the high frequency drift of hydrogen clock, and the judgment is related to the improvement of hydrogen clock technology and the calculation of smoothing time. Compared with hydrogen clock, rubidium clock’s frequency stability performance is closely matched. The frequency accuracy of cesium clock is the best, but the key stability performance is poor. It shows that hydrogen clock and rubidium clock are the best choice of GNSS satellite clock, and it has certain reference value for the research and development and engineering practice of the new generation of spaceborne atomic clock.