提高卫星导航定位精度和实时性的选星算法

Satellite selection algorithm to improve precision and real-time performance of GPS positioning

通过分析卫星数目及一颗卫星对GDOP的影响,可知GDOP随卫星数目增加单调递减,但递减幅度变小。综合考虑GPS定位精度和实时性,确定采用6星组合进行定位;基于卫星对GDOP贡献的定义,提出了两种选星算法,并与最佳几何精度因子算法进行了性能比较分析。仿真结果表明,6星组合与全部可见星的GDOP差别不大;提出的两种基于卫星对GDOP贡献的选星算法与最佳几何精度因子算法的选星结果基本相同,而计算量远小于后者,因此具有较好的性能。

Based on an analysis of the influence of both the number of satellites and one satellite to GDOP, it is concluded that GDOP progressive decreases dully with the increase of the number of satellites, but the decreasing amplitude reduces. With consideration of both GPS positioning precision and real-time performance, a combination of 6 satellites is selected to calculate position. Based on the definition of the contribution to GDOP, two satellite selection algorithms are proposed, whose performance is compared with the best GDOP algorithm. Simulation results indicate that there is little difference between the GDOP of 6 satellites and that of all observed satellites, and the two algorithms proposed by this paper have almost the same selected satellites with that of best GDOP algorithm, but with much less computations.