基于不同轨道和星钟类型的BDS-3星载钟特性评估

Characteristic Evaluation of BDS-3 Onboard Clock Based on Different Orbit and Satellite Clock Types

星载原子钟性能的研究对于卫星钟差估计与预报、卫星导航系统的建设与维护等具有重要的意义。采用了德国地学研究中心(GFZ)2021-01-01—2021-12-31多星定轨联合解算的精密钟差产品,基于预处理后的钟差数据,对2021年北斗三号卫星导航系统(BDS-3)星载钟的相位、频率跳变情况进行了统计,探讨了中圆地球轨道(Medium Erth Obit,MEO)卫星铷钟与氢钟的相位、频率序列图特点。使用二次多项式模型分析了BDS-3不同轨道、不同星钟类型卫星钟的频率漂移率和模型噪声等指标的变化规律,基于哈达玛方差从不同时间尺度对BDS-3卫星钟的频率稳定度展开了分析。结果表明,BDS-3卫星钟相位和频率变化相对连续且稳定,其中仅地球静止轨道(Geostationary Orbit,GEO)卫星星钟存在调相行为,MEO卫星和GEO卫星都存在调频行为,且铷钟的调频次数明显多于氢钟。从频漂和模型噪声水平来看,MEO卫星优于其他轨道类型卫星,同铷钟相比,氢钟性能更优。BDS-3星载原子钟的稳定度保持在10^(-15)~10^(-14)量级,MEO卫星星载钟的稳定度最优,其次是倾斜地球同步轨道(Inclined Geosynchronous Orbit,IGSO)卫星,GEO卫星星载钟的稳定度最差。

The study of the performance of onboard atomic clocks is of great significance for the estimation and prediction of satellite clock error and the construction and maintenance of satellite navigation systems,etc.Based on the pre-processed clock error data,the phase and frequency hopping of the Beidou Global Navigation Satellite System(BDS-3)onboard clocks for 2021 have been counted based on the precision clock error products of multi-satellite orbit determination joint solution of the GFZ from 2021-01-01 to 2021-12-31.The phase and frequency sequence diagrams of rubidium and hydrogen clocks of Medium Earth Orbit(MEO)satellites are discussed.A quadratic polynomial model is used to analyze the variation of frequency drift rate and model noise of BDS-3 onboard clocks with different orbits and different clock types,and then the frequency stability of Beidou-3 satellite clocks are analyzed from different time scales based on Hadamard variance.The results show that the phase and frequency changes of BDS-3 satellite clocks are relatively continuous and stable,among which only the Geostationary Orbit(GEO)satellite clocks have phase tuning behavior,and both MEO and GEO satellites have frequency tuning behavior,and the frequency tuning of rubidium clocks is significantly more than that of hydrogen clocks.MEO satellites outperform other orbital types in terms of frequency drift and model noise levels,and hydrogen clocks perform better compared to rubidium clocks.The stability of the BDS-3 onboard atomic clock is maintained in the order of 10^(-15) to 10^(-14).The stability of the MEO onboard clock is the best,followed by the inclined geosynchronous orbit(IGSO)satellite,and the GEO satellite on-board clock is the worst.