基于X射线脉冲星的导航卫星自主导航

基于星间链路的导航星座自主导航,存在星座整体旋转误差随时间累积问题,致使星座难于长时间自主运行。X射线脉冲星导航为星座整体旋转问题提供了一种新的解决途径:在导航卫星上安装X射线探测器,探测脉冲星辐射的X射线光子,整合脉冲轮廓和提取影像信息,星载时钟记录脉冲到达时间,经过星载计算机处理得到卫星位置、速度、时间和姿态等导航参数;脉冲星辐射的X射线信号为导航卫星提供了绝对时空基准,不存在星座整体旋转问题。在简要论述基于X射线脉冲星的导航卫星自主导航的基本概念、系统组成和几何原理的基础上,重点研究了导航卫星轨道确定与时间同步的自适应卡尔曼滤波算法,并通过数值分析试验,初步论证利用X射线脉冲星解决自主导航星座整体旋转问题的可行性和合理性。

Autonomous Navigation for Navigation Satellites Based on X-ray Pulsars

Constellation rotation errors accumulating with time is a problem for the autonomous navigation constellation based on the cross-links.It is very difficult to keep the constellation autonomously operating for a long time.A new approach to solve the constellation rotation issue is using the X-ray pulsar navigation(XPNAV).When the X-ray photons from the pulsars are detected with the on-board detector,the pulse profile of the pulsar is folded and the image also obtained.And then pulse arrival time is recorded with the on-board atomic clocks.Moreover,the navigation parameters for the satellites,including the position,velocity,attitude and time,can be determined accurately by the data processing with the on-board computer.Since the X-ray signal from the pulsar provides an absolute space-time reference for the navigation satellites,consequently there is not the constellation rotation issue.The basic concept,system composing and geometric principle of XPNAV were described briefly.Especially,the adaptive Kalman filtering algorithms of the orbit determination and time synchronization for the navigation satellites were studied in detail.According to the numerical analysis results,the feasibility and rationality to solve the issue of the autonomous navigation constellation rotation using the X-ray pulsar is demonstrated.