Closed-loop filter design for X-ray pulsar-based satellite navigation system
X射线脉冲星导航系统的闭环校正滤波器设计

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 dynamics. 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.