DRO卫星编队同波束差分相对导航

Single-Beam Differential Relative Navigation of DRO Satellite Formation

针对地月空间远距离逆行轨道(Distant Retrograde Orbit,DRO)卫星编队相对导航的需求,提出一种同波束差分相对导航方法。在地月空间中,2颗DRO卫星所构成的编队可被1颗近地球轨道(Low Earth Orbit,LEO)卫星发出的测量波束所覆盖,从而与该LEO卫星同时建立2条观测链路。由这2条测量链路得到的差分测量数据与地月三体轨道动力学模型相结合,即可实现DRO卫星编队相对导航。DRO处于地月三体引力场非对称性较强的空间,根据LiAISON原理,运行于该轨道的卫星与LEO卫星建立的1条测量链路即可实现自主导航,从而可确定其中1颗DRO编队卫星与LEO卫星的绝对轨道状态。同波束差分相对导航方法以两星的绝对状态作为约束条件,利用差分测量数据消除测量中的共同误差,可获得DRO卫星编队的高精度相对状态。分别对DRO近距离卫星编队(星间距离为50km)及DRO远距离卫星编队(星间距离为数万km)相对导航的性能进行了仿真测试。结果显示,星间测距噪声为0.5m时,相对导航位置精度为5m,该结果比利用绝对导航作差提高了4倍。

This paper proposes a single-beam differential relative navigation method to solve the relative navigation requirements of Distant Retrograde Orbit(DRO)satellite formation in cislunar space.The formation of two DRO satellites can be covered by a beam of measurement sent by a Low Earth Orbit(LEO)satellite,thus establishing two Satellite-to-Satellite Tracking(SST)links with the LEO satellite at the same time.Then differential measurement data can be obtained by these two SST links.This method can get relative states of the DRO satellite information by combining the differential measurement data and three-body orbital dynamics model.DRO is in the space with high asymmetry of the Earth-Moon three-body gravitational field,according to the LiAISON principle,a SST link established between the satellite running on this orbit and an LEO satellite can realize autonomous navigation,thus determining the absolute orbit states of one of the DRO formation satllites and the LEO satellite.The single-beam differential relative navigation method uses the absolute states of two satellites as constraints,and the advantage of using differential measurement data to eliminate common errors can obtain high-precision relative states of DRO satellite formation.In the simulation test,the relative navigation performance of the single-beam differential relative navigation method of the short-distance DRO satellite formation(inter-satellite distance of 50 km)and the long-distance DRO satellite formation(the distance between the satellites is about tens of thousands of kilometers)is tested.And the results show that,when the inter-satellite ranging noise is 0.5 m,the relative navigation accuracy calculated by the method proposed in this paper is 5 m(1σ),which is 4 times higher than the relative navigation accuracy calculated by differencing the absolute orbit.