基于星间链路技术的GEO卫星定轨精度分析

The Precision Analysis of Determined Orbit of GEO SatelliteBased on Inter-Satellite Link

摘要:

地球静止轨道(GEO)卫星具有对地静止的特性,GEO 卫星应用日益增多,在高分辨率对地观测、气象、通信等领域都发挥着越来越重要的作用,对其轨道确定的需求也越来越高,研究GEO卫星的高精度定轨技术迫在眉睫。传统方法中利用地面站对GEO卫星实现实时自主定轨存在系统误差大、观测几何差等问题,导致星地测量的误差在定轨过程中被放大的倍数急剧增加,影响了GEO卫星定轨精度的提高。利用GPS卫星实现对GEO卫星的定轨时存在可见GPS卫星数量少,接收到的信号微弱,测量精度不够的问题。星间链路具有对GEO卫星观测几何好、测量精度高的优点,为GEO卫星定轨开辟了新思路。针对在星间链路资源有限情况下如何选择MEO卫星组合与GEO卫星进行建链的问题,以星间链路构型的PDOP值为优化指标,对MEO卫星对PDOP值的影响进行了分析,提出了遍历选星、直接选星、迭代选星三种链路资源配置策略,确定与GEO卫星进行建链观测的MEO卫星组合,并用仿真方法对三种算法进行验证,结果表明,提出的迭代选星的链路资源配置策略,能将GEO卫星的定轨精度维持在7~40m以内,同时将星间链路的使用效率提高5~120倍。

Abstract:

The geostationary orbit satellite is relative to the earth, it has been widely used in more and more applications,such as earth-observation,weather and comunication, the required precision of the GEO satellite orbit has become more and more accurate, so the research on GEO orbit determination has become extremely urgent. In traditional method, the ground station is used to realize the orbit determination of GEO satellite, there is a problem that the observation geometry among the GEO satellite and MEO satellites is weak, it leads to the result that the error of satellite-ground station observation will be amplified too much. The visible MEO satellite is few and the signal is weak when using GPS to determine the orbit of GEO The Inter-Satellite Link (ISL) whose observation geometry is much better, it has opened up new method to realize the orbit determination of GEO satellite. To solve the limited ISL source problem, three source allocation strategies have been put forward to determine the group of MEO satellites in this paper, the precision and accuracy of the algorithm is verified by simulation data. The result shows that the iteration strategy ensures the accuracy of GEO satellite orbit in 7m~40m and increases the coefficient of ISL about 5~120 times simultaneously.