GPS/VISNAV integrated relative navigation and attitude determination system for ultra-close spacecraft formation flying

For the improvement of accuracy and better fault-tolerant performance, a global position system （GPS）/vision navigation （VISNAV） integrated relative navigation and attitude determination approach is presented for ultra-close spacecraft formation flying. Onboard GPS and VISNAV system are adopted and a federal Kalman filter architecture is used for the total navigation system design. Simulation results indicate that the integrated system can provide a total improvement of relative navigation and attitude estimation performance in accuracy and fault-tolerance.

基于改进的无迹卡尔曼滤波确定视线感知相对状态

基于视线传感器原理,研究了如何确定摄动作用下两颗卫星间相对状态的问题。采用VISNAV传感器作为相对状态传感器,并应用一种改进滤波算法实现了问题求解。首先,考虑了两颗卫星间相对位置与相对姿态的运动方程及摄动作用的影响,给出了改进的离散系统方程及其误差协方差矩阵的取值方法,避免了复杂协方差矩阵的实时额外求解,降低了算法计算量及实施难度。最后,给出相应的无迹卡尔曼滤波(UKF)算法并通过STK和MATLAB软件进行了数值仿真实验。分析表明,改进后的算法保证了收敛性,数值仿真及对比仿真验证了本文方法的可行性和有效性。在摄动因素作用的前提下,改进的方法能够在200m的相对距离内达到角秒级的相对姿态确定精度和毫米级的相对位置确定精度,完全可以满足近距离自由飞行卫星间的相对状态确定要求。