摘要:
本文提出一种基于两步Kalman滤波的GNSS分布式自主导航定轨方法。首先，给出分布式自主定轨数据流程，建立并分析GNSS导航星座星间链路双向伪距测量模型。其次，采用单点定位法计算待估卫星位置及其协方差，以此作为伪观测量，采用两步Kalman滤波法处理卫星计算轨道参数改正数，并进行时间更新。另外，针对自主定轨存在的秩亏问题，利用卫星预报星历中轨道定向参数控制星座整体旋转，给出卫星真实轨道的最佳估值。仿真结果验证了该方法的有效可行性。
Abstract:
This article presents an autonomous orbit determination method for distributed GNSS based on two-step Kalman filter. Firstly, the paper gives the distributed autonomous orbit data process, and then builds the bidirectional pseudo-range measurement model for ISLs of GNSS navigation constellation. Secondly, the single point positioning method is adopted to obtain the position and covariance of satellite, which are the pseudo-observations to calculate the orbit correction parameters by the two-step Kalman filter. According to the problem of rank deficiency of autonomous orbit determination problem, the paper gets rid of the unobservable rotation of constellation by constraining orientation of prediction orbit, and then gives the best estimated value of the satellite orbit. The simulation and analysis results illustrate the availability of the scheme.