基于扩展卡尔曼滤波的X射线脉冲星相对导航方法

X-ray pulsar relative navigation approach based on extended Kalman filter

X射线脉冲星作为一种天然时间基准,具有良好的周期稳定性,在深空探测航天器自主导航方面具有重要的应用前景。针对绝对导航的整周模糊度求解问题和相对导航的预报相位、标称轨道存储问题,提出了一种改进的相对导航方法,将前一时刻的航天器位置作为相对导航基准,建立航天器轨道动力学模型,采用扩展卡尔曼滤波算法,确定航天器的位置。最后,进行了数学仿真研究,仿真结果表明:脉冲星相对导航改进方案的导航精度达到1 km,滤波器一致渐进稳定,能够快速抑制初始误差和轨道根数的干扰,验证了导航方案的正确性和可行性。

X-ray pulsar as a nature timing standard has excellent period-stability, and pulsar navigation has important application prospect. An improved relative navigation approach which selects the previous position as the navigation reference is presented to solve the integer ambiguity problem in absolute navigation and the storages problem of the phase and the nominal orbit in relative navigation. The information filtering is implied to estimate the precise relative position and velocity by stabling the orbit dynamics model. Finally, the simulations are performed, which show that the accuracy of the improved relative navigation reaches 1 km. The interferences of the initial error and the orbital elements are rapidly suppressed by the filter, which is uniformly asymptotically stabilized. The navigation program is verified to be valid and feasible.