星载全空间可见GPS接收系统定位精度分析及验证

针对低轨空间科学卫星在轨任意姿态无固定对天面造成的无法连续GPS(Global Positioning System,全球定位系统)定位的问题,在HXMT(Hard X-ray Modulation Telescope,硬X射线调制望远镜)卫星中提出了星载全空间可见的GPS接收系统,并指出了双天线多径干扰对定位精度的影响。建立模型,对双天线下主瓣直达信号和后瓣镜像干扰信号叠加合成的信号进行定位精度分析,结果表明,空间中83.3%以上的GPS卫星信号对该系统带来的定位误差影响不大于单天线的定位误差影响。通过半物理动态仿真验证以及外场试验进行验证,实际工程测试数据结果表明采用剔星策略后定位精度提高约13.4%。从而证明了星载全空间可见的GPS接收系统方案的正确性,并可广泛应用于工程实际。

Analysis and Verification of the Positioning Accuracy of a Space-Borne All-Direction Visible GPS Receiving System

A space-borne all-direction visible Global Positioning System (GPS) receiving system was proposed in Hard X-ray Modulation Telescope (HXMT) satellite to solve the problem of discontinuity of GPS positioning due to the random attitude of Low Earth Orbit (LEO) space science satellites. The influence on positioning accuracy from the multipath interference of dual-antenna was presented as well. The positioning accuracy of signals was analyzed based on modeling in this paper, covering the main lobe direct signals and the back lobe mirror interference signals from the two antennas. The results indicate that the positioning accuracy of the system by using RF combiner is no more than the system with a single antenna from more than 83.3% GPS satellites. According to semi-physical simulation and outdoor experiments, the actual engineering test data results indicate that positioning accuracy increases by 13.4% by removing satellites under co-viewer. This paper proves the correctness of the space-borne all-direction visible GPS receiving system and it can be widely used in engineering.