导航星座不完整对星间自主定轨几何精度因子的影响

摘要

Navigation satellites Autonomous Orbit Determination (AOD) using inter-satellite link is the key technology of the constellation autonomous navigation.In conditions such as uncompleted constellation establishment on the early construction, malfunction and destruction of satellites, several satellites of the constellation may be unavailable, therefore the research of constellation incompleteness' effect on satellites AOD is valuable.Based on presenting the AOD method of weighted least squares solution one by one, this paper introduced the AOD Dilution of Precision (DOP) values as merit index and analyzed the effect of the Galileo constellation by simulations.The results show that the visual satellites are quite redundant in satellite's AOD process of the Galileo constellation,and there is no prominent effect of constellation incompleteness on the AOD dilution of precision.Only when the number of satellites is reduced by 2/3, there will be several satellites whose DOP values of AOD exceed the threshold.The method is also adoptable in analysis of other navigation constellation.%星间自主定轨是星座自主导航的关键技术.在系统建设初期未完成全星座组网、卫星出现故障或受损等情况下,部分卫星缺失将导致导航星座不完整,其对星间自主定轨性能的影响值得研究.本文在提出逐卫星加权最小二乘自主定轨估计方法的基础上,引入几何精度因子作为衡量星座不完整影响卫星自主定轨性能的指标,最后以Galileo星座为例进行了仿真与分析.结果表明,Galileo星座中卫星进行自主定轨时其可视卫星的冗余度较高,少数卫星缺失不会对星闻自主定轨的几何精度因子产生明显影响.只有当星座缺失卫星数达2/3时,会使得部分卫星的几何精度因子超差,卫星自主定轨性能明显下降.