GPS两种广播星历参数拟合及外推精度分析

ACCURACY ANALYSIS OF TWO GPS BROADCAST EPHEMERIS FITTING AND EXTRAPOLATION ALGORITHM

给出了GPS系统现有导航电文与现代化后导航电文的参数拟合算法,比较分析采用两种不同广播星历参数进行轨道拟合与外推的精度。结果表明,在相同拟合时长下,18参数算法拟合精度高出16参数近一个数量级,外推2小时卫星轨道计算时,18参数算法优于16参数。参照目前的GPS广播星历更新策略,采用16参数4小时轨道拟合,误差损失约为14cm,采用18参数3小时轨道拟合,误差损失约为1cm。

A parameter fitting algorithm was studied for the current broadcast ephemeris and the modernizing broadcast ephemeris which were used to analyze the orbit fitting accuracy and orbit extrapolating accuracy respec- tively. It was shown that the 18-parameter algorithm is an order of magnitude higher than the 16-parameter algo- rithm for the orbit fitting accuracy in the same fitting interval, and the 18-parameter algorithm is better than the 16- parameter algorithm for the 2-hour orbit extrapolation. According to the current GPS broadcast ephemeris update strategy, the 4-hour orbit fitting by the 16-parameter algorithm could have the accuracy by 14cm, while the 3-hour orbit fitting by the 18-parameter algorithm could have the accuracy by lcm.