X射线脉冲星导航系统的闭环校正滤波器设计

Closed-loop filter design for X-ray pulsar-based satellite navigation system

X射线脉冲星导航(XNAV)系统对脉冲到达时间或相位的在轨测量存在星载钟计时误差问题.本文提出将钟差与卫星三维位置参数一起作未知量处理,采用4颗以上脉冲星的观测信息解算出卫星位置;将该位置信息与轨道动力学预报的位置信息的差值作为量测信息,结合卫星轨道动力学模型,设计闭环校正卡尔曼滤波器.仿真表明,设计的闭环校正滤波器能够对卫星轨道状态进行最优估计,解决了XNAV系统中的钟差问题.

The measurement of the pulse arrival time or phase on the satellite is affected by the satellite clock bias in the X-ray pulsar-based satellite navigation（XNAV） system. The clock bias and the satellite position in three dimensions are processed as the unknown quantities, and are determined with the measured information from more than four pulsars. Using the difference of the determined positions and positions predicted by orbit dynamics, we obtain the measurement information. The closed-loop Kalman filter is designed to incorporate the measurement information and the satellite dy- namics. Simulation demonstrates that the orbit can be estimated optimally by the designed closed-loop filter, which solves the problem of the clock bias within the XNAV system.