地面测控站分布对北斗卫星精密定轨的影响

Research on the influence of monitoring stations distribution on precise orbit determination of BeiDou constellation

北斗卫星精确定轨是北斗卫星导航系统应用与服务的核心技术,而地面测控站的分布是影响其精度的主要原因之一。针对北斗卫星地面跟踪站的现状,该文基于几何法定轨的基本原理,将卫星定轨的观测方程线性化,根据位置精度衰减因子值的构成,分析了测站分布与卫星定轨精度之间的关系。通过3种实验方案,对比不同测站分布和测站数量对北斗卫星定轨精度和计算效率的影响。实验结果表明:仅利用现有iGMAS站和BETS站的观测数据,很难获取高精度的北斗定轨结果;增加国际MGEX的北斗数据后,定轨精度有明显提高,尤其体现在GEO卫星切线方向;利用40个全球均匀分布的北斗站与利用70个站的定轨精度相当,但前者的解算效率较后者可提高近1倍。

The precise orbit determination of BeiDou constellation is the core technology of application and service of BeiDou navigation satellite system,and the station distribution is one of the main factors affecting the accuracy of precise orbit determination.Firstly,the basic principle of geometry orbit determination was introduced and the observation equation was linearized in this paper.Secondly,the relationship between stations distribution and the accuracy of precise orbit determination was analyzed according to the dilution of precision（PDOP）.Thirdly,three experimental schemes were designed and a number of global BeiDou data were processed,in which the station distribution and number of each scheme were different.The results showed that it was difficult to obtain high precision results of orbit determination when iGMAS and BETS data were processed only.If more MGEX data involved in the experiment,orbit determination accuracy was improved significantly,especially in the along-track direction of GEO.Though the orbit determination accuracy of 40 evenly spaced stations and 70 global stations was almost the same,the efficiency of the former was almost two times than the latter.