一种改进的组合导航系统选星算法

针对GPS,GLONASS,BDS组合导航系统定位中卫星的选择作了相关分析。首先用STK软件进行仿真,分析几何精度因子与卫星数的关系,得出组合导航系统最佳选星数;再根据卫星星座的空间几何分布,基于次优选星算法的成本函数模型,结合各导航系统卫星测量精度的差异性以及次优选星算法的峰值、不稳定特点,构建一种以卫星高度角和载噪比确定的加权成本函数模型,提出一种依据加权成本函数选星的分步次优加权选星算法。实验结果表明,该选星算法能近似到达最优选星算法的效果,计算负荷也相对较小,可满足导航定位解算精度和实时性要求。

An improved satellite selection algorithm for integrated navigation system

This paper analyzes the selection of satellites for GPS,GLONASS and BDS integrated navigation system.Firstly,the relationship between the geometric dilution of precision GDOP and the number of satellites is analyzed with STK simulation to obtain the best SVs selection.Secondly,according to the spatial distribution of satellite constellation,based on the cost function of quasi-optimal satellite selection algorithm,and combined with the difference in measurement precision of satellites for integrated satellite system,the peak value and unstable characteristics of quasi-optimal satellite selection algorithm,a weighted cost function model is built determined by the satellite elevation angle and signal to noise ratio. And a step-by-step quasi-optimal weighted satellite selection algorithm is proposed based on the weighted cost function.Experimental result show s that the proposed algorithm can approximate the effect of the optimal selection algorithm,and the computational load is relatively small,w hich can satisfy the accuracy and real-time requirements of navigation and positioning solution.