Performance Evaluation of the Beidou Satellite Clock and Prediction Analysis of Satellite Clock Bias

Abstract

Satellite clock bias (SCB) is provided by the in orbit atomic clock, which is the key to satellite navigation system. First, the time reference of the satellite navigation system is realized by the SCB, and the SCB prediction accuracy will also affect the positioning accuracy of real-time navigation users. With the development of our Beidou satellite navigation system (BDS), the performance requirement of the satellite clock and accuracy requirement of the SCB prediction are higher and higher. This paper will study on performance evaluation of BDS atomic clock and the prediction analysis of SCB series exclusively. In order to show the results objectively and effectively, we select two data processing centers of the GeoForschungsZentrum Potsdam (GBM), and SHAO Analysis Center (SHA), to obtain the same time BDS clock bias sequence as the base data, for a comparative analysis. First, the performance of the atomic clock is evaluated by statistics of the Allen variance. Meanwhile, we establish the model for each SCB sequence according to the characteristic of the atomic clock, by using a combined method of least squares and autoregressive model (LS+AR), to predict and assess the SCB with root mean square error (RMS). Results show that the performance of BDS in orbit atomic clock is stable, with the day stability in the order of 10⁻¹⁴; And the atomic clock performance is related to the SCB prediction accuracy, that is shown as better performance with higher prediction accuracy; Mean while the LS+AR model predict SCB series based on the performance of different atomic clocks, which can improve the SCB prediction accuracy effectively.