分布式导航星座自主时间同步性能评估

针对星座自主导航任务需求，分析了基于星载钟性能和星间相对钟差估计星座自主时间同步精度的可行性，验证了星座中星载原子钟性能与卫星自主时间同步滤波结果的相关性，评估了有无时间参考基准、星间电文交互条件下的卫星钟差预报性能。评估结果表明：当缺少地面或参考星为基准且星间电文无交互时，单颗卫星的自主钟差预报结果是不可观的，会随着时间增长发生偏移，并在地面或基准星对其校准后迅速收敛，继续随星载钟性能和滤波状态参数发散；当缺少基准且星间电文正常交互时，卫星自主钟差滤波结果与精密钟差相比存在整体偏移；基于本文设计的验证条件，卫星自主运行15 d卫星钟差整体漂移量优于60 m；当以某颗卫星或锚固站为时间参考基准时，全网卫星可根据与基准时间的相对钟差进行自主校准，星间相对钟差RMS为0.6 m。

Distributed performance evaluation and autonomous time synchronization of navigation constellation

As to the autonomous navigation requirements,the paper analyzes the availability of the autonomous time synchronization with relative clock error and on-board atomic clock,verified the coherence between the on-board atomic clock characteristic and autonomous filtering clock result,and estimated the clock prediction peculiarity within/without time reference and inter-satellite message.The results demonstrate that the clock error prediction result will be not available and increase with onboard clock characteristic and filtering parameters when the reference time of ground or other satellite and inter-satellite message are missed,and has fast convergence ability as the satellite receives the time reference information;other satellites can autonomously adjust with some satellite or anchor station as clock reference;when inter-satellite message can be satisfied,the constellation clock error has integrate draft;as to the designed algorithm,the integrate draft can reach 60 m;autonomous time synchronization error based on the onboard absolute clock error is rather stable which does not increase with time,and the relative clock error RMS is 0.6 m.