GPS广域增强系统星历和星钟改正及用户性能分析

Correction of the Ephemeris and Satellite Clock of GPS Wide Area Augmentation System and User Performance Analysis

研究并程序实现了GPS广域增强系统的星历及星钟差分改正和故障监测算法。为了评估分析算法的性能,选取美国均匀分布的17个GPS测站作为监测站,计算了2016年年积日183～189共7天的卫星星历和星钟的差分改正,基于此改正信息的定位精度相对于伪距单点定位一般可提高60%;在广域增强系统的边缘地区效果稍差,定位精度可提高约30%,总体来看,差分改正数精度可满足Ⅰ类精密进近的定位精度要求;在卫星星历故障情况下,程序可以很好地识别出故障卫星并发出告警信息;在卫星钟斜坡类故障情况下,程序不仅能够计算有效的星钟差分改正数,而且能够准确地估计其变化率。

The ephemeris and satellite clock differential correction and fault monitoring algorithm of GPS wide area Augmentation system are studied and programmed. In order to analyze the performance of the algorithm,the ephemeris and satellite clock error corrections over the period of the day 183 to 189 of 2016 are calculated by using 17 GPS monitoring stations which even-distributed in USA. The user positioning accuracy is improved by 60% compared with the single point positioning. On the edge of the wide area augmentation system, the accuracy is improved by 30%,slightly degraded. In general, the accuracy of differential corrections can meet the positioning accuracy requirements of CAT I precision approach. In the case of satellite ephemeris fault, the program can effectively identify the faulty satellite and issue a warning;In the case of the satellite clock step-type fault, the program can compute the clock differential corrections. When satellite clock ramp-type fault occurs, the program can not only compute the corrections of the satellite clock, but also accurately estimate the rate of fault.