GNSS星载原子钟性能评估

星载原子钟作为导航卫星上维持时间尺度的关键载荷，其性能会对用户进行导航、定位与授时的精度带来影响。介绍了原子钟评估常用的三个指标（频率准确度、飘移率和稳定度）的定义及计算方法，利用事后卫星精密钟差数据，开展了全球卫星导航系统（global navigation satellite system，GNSS）星载原子钟性能评估，分析了GNSS星载原子钟特性。结果表明，GPS（global position system）BLOCKIIF星载铷钟与Galileo星载氢钟综合性能最优；北斗系统中地球轨道卫星与倾斜同步轨道卫星星载原子钟天稳定度达到2~4×10-14量级，与BLOCK IIR卫星精度相当；频率准确度达到1~4×10-11量级；频率漂移率达到10-14量级。

Performance Evaluation of GNSS On-board Atomic Clock

On-board atomic clock as the key to maintain the time scale, its performance will affect the navigation, positioning and timing of the user's accuracy. The definition and calculation method of atomic clock frequency accuracy, drift and stability were introduced, using satellite clock error data provided by iGMAS, IGS and MGEX in the GNSS on-board atomic clocks performance assessment. And, on this basis we analyzed the characteristics of GNSS on-board atomic clocks. The results show that the rubidium clocks on GPS BLOCK IIF and the space borne hydrogen clocks in Galileo system have the best comprehensive performance; the day stability of BDS MEO and IGSO on-board atomic clocks have reached the level of 2~4×10-14, almost the same precision as the GPS BLOCK IIR satellites; and the frequency accuracy reached the level of 1~4×10-11, and the frequency drift reached the level of 10-14.