北斗卫星导航系统X射线脉冲星可见性分析

X射线脉冲星可以为深空乃至近地航天器提供全源、自主、高精度的导航服务.对近地航天器而言，由于中心天体的遮挡，脉冲星信号并非全程可见，所以X射线脉冲星的可见性成为近地导航应用中挑选脉冲星的关键因素，也是脉冲星导航的首要工作.本文对挑选出的30颗X射线脉冲星在北斗系统7个轨道面上的可见性进行了仿真分析，得出了一天内可见脉冲星数量的变化情况以及一年内太阳、地球和月球遮挡的仿真结果,总结了影响脉冲星可见性的天体的遮挡规律，为利用脉冲星对北斗卫星进行自主定轨和守时提供了数据支持.

Visibility Analysis of X Ray Pulsar for Beidou Navigation Satellite System

The X ray pulsar can provide navigation information of the position, velocity, attitude and time with high precision autonomously for the spacecraft in the deep space and near Earth orbit. But for the spacecraft around the Earth, the pulsars are sometimes invisible due to the eclipse of the central body, so the visibility of pulsars becomes a key factor on the near Earth navigation application of the X ray pulsars navigation (XPNAV). This paper analyzes the visibility of 30 pulsars picked for the 7 orbits of the Beidou System. The simulation results of the number of the visible pulsars in one day are obtained and the situations of the eclipse of the Sun, Erath and Moon in one year are also presented. The rules of the influence of the celestial bodies on the visibility of pulsars are summarized in this paper, which can provide a data support for the autonomous orbit determination and time keeping of the Beidou System by using the XPNAV.