北斗导航卫星迭代双向卡尔曼滤波定轨

Orbit Determination for Beidou Navigation Satellite System Using Iterative Two-way Kalman Filter

以不同天的广播星历拟合初值结果作为北斗星导航系统(BDS)卫星轨道解算参数初值,分析了状态参数不同初始值对BDS双向卡尔曼滤波定轨结果的影响。针对卡尔曼滤波系统不稳定时或弧段长度未能使卡尔曼滤波达到稳定时,初始值的误差对BDS卫星滤波结果影响较大的情况,提出了将双向卡尔曼滤波定轨解算得到的卫星初始历元状态参数估计值作为初值,其他参数初值重新解算,初始方差保持不变,进行迭代计算的迭代双向卡尔曼滤波定轨算法。实验结果表明,在相同初始先验方差的情况下,迭代双向卡尔曼滤波定轨方法整体提高了BDS卫星轨道精度。

The result of BDS Kalman filter orbit determinationis analyzedby the status parameters of different initial values,and the initial results of broadcast ephemeris in different days are used as the initial parameters of BDS orbit solution. For Kalman filtering system is unstable and the length of segmental arc fails to be long enough to make Kalman filter keep stable,errors of initial values have a great influence on the results of the filtering process. Therefore,an iterative two-way Kalman filtering algorithm is put forward,in which values worked out by using two-way Kalman filtering are considered as initial values to solve the orbit determination of satellites and the other parameters are re-settled with the same variance. The experimental results showed that if the initial prior variances stay the same,the iterative two-way Kalman filtering method will improve the precision of the orbit determination.