Accuracy and reliability of BeiDou clocks

Abstract The subject of this paper is the analysis of the stability of BeiDou system clocks; currently only signals from two blocks, BSD-2 and BDS-3, are available. For elaboration, 30 s clock corrections from the 2014 to 2020 period for 37 satellites were used (9 IGSO, 28 MEO). Four different Allan variances were used to determine stability, and additionally, the type of noise characteristic for each satellite was also determined. Based on the calculations, it was shown that the BDS-2 segment has a significantly lower stability than BDS-3. Moreover, it was possible to notice a difference in the course of the graphs of the same satellites using different variances. BDS-2 satellites were mostly characterised by the presence of WFM noise, while BDS-3 satellites were characterised by WFM noise for the shortest averaging times and RWFM for the other intervals. Accuracy varies between 10−10 s to 10−6 s for a rubidium clocks in general, in case of the hydrogen masers in is between 10−14 s to 10−10 s.