基于星间链路的导航星座自主时间同步算法设计

Research on Autonomous Time Synchronization Algorithm for Navigation Constellation Based on Inter-satellite Links

导航星座自主时间同步算法是自主导航研究中一个迫切需要解决的课题。在分析国内外相关研究的基础上,深入研究导航星座自主时间同步算法。首先建立导航卫星自主时间同步的钟差模型和状态方程。根据导航卫星星间双向测距和星间通信的过程,建立自主时间同步的观测方程。设计基于Kalman滤波的分布式自主时间同步算法,并进行仿真实验验证。仿真结果表明,设计的方程和算法能够较好地实现导航星座自主时间同步,当星间测距误差为3m时,导航星座自主时间同步精度仍在4ns以内,并且时间同步精度随着测距误差的减小而提高。

The Autonomous Time Synchronization(ATS) algorithm is a crucial issue in the research on autonomous navigation.Based on the analysis of relevant studies at home and abroad,deep researches on the ATS algorithm are conducted.First of all,the clock error model and state equations for ATS are established.Moreover,based on the process of inter-satellite ranging and communication,measurement equations are established.The distributed ATS algorithm based on Kalman filtering is designed and the experimental verification based on simulation is conducted.Simulation results indicate that the ATS for navigation constellation can be well realized through the equations and algorithms designed in this paper,when the inter-satellite ranging error is 3m,the precision of ATS is below 4ns,and the precision of ATS increases with the decrease of ranging error.