卫星定位误差的最优星座选择剖析

在分析定位误差的基础上,研究了星座最佳几何配置,以及几何位置相对较好、星的个数较少的4颗卫星的定位问题,并给出了星座的最佳几何分布与定位误差的关系仿真.结果表明,在卫星星座中,星的高度与分布的均匀性是决定星座几何精度的衰减因子,顶座星、底座星的仰角与方位角之差则是几何精度衰减因子的影响因素.通过计算和实验发现,在GPS系统的定位过程中,有一组最优的、由4颗卫星组成的几何配置星座,此时对应的几何精度衰减因子最小,为1.581 2.

Analysis of Optimal Constellation Selection Based on Satellite Positioning Error

In order to improve the positioning precision of satellites and minimize their positioning error,the optimal geometric configuration of the constellation and 4 satellites positioning problem which has relatively better geometric position and lesser number of satellites are studied on the basis of analysis on the positioning error of satellites.The relationship of the optimal geometric distribution of the constellation and the positioning error is given.Simulation results indicate that in the satellite constellation,the geometrical dilution of precision(GDOP) of the constellation is determined by the height and uniformity of the distribution of the satellites.The difference between the elevation and azimuth angle of topmost and lower satellites also are influence factors of GDOP.By the calculation and experiments,it is shown that in course of GPS systems positioning,there exists a set of optimal geometric configuration constellation consisted of four satellites,and the corresponding GDOP is minimum,i.e.1.5812.