最差用户位置算法研究与仿真分析

Worst User Location Algorithm and Simulation Analysis

在计算Galileo卫星导航系统空间信号误差(SISE)、空间信号精度(SI-SA)和空间信号监测精度(SISMA)时需要用到的一个关键参数——最差用户位置(WUL)。WUL表示空间信号的轨道误差在卫星覆盖域内所导致的伪距误差最大的位置,WUL的确定可以帮助系统向用户提供正确可靠的SISA、SISMA和完好性标志(IF)等完好性信息,对提高系统的可靠性和可用性具有非常重要的意义。WUL的算法主要有两种:临界圆法和网格搜索法。详细介绍两种算法的基本原理与计算流程,比较两种算法的结果,并基于全球和区域完好性监测的概念对二者进行分析评价。

This paper proposes the worst user location （WUL） , which is a key parameter to evaluate the signal-in-space error （SISE） , signal-in-space accuracy （SISA） , and signal-in-space monitoring accuracy （SISMA） of the Galileo satellite navigation system. WUL is referred to as the position with the maximum range error caused by satellite orbit error in the satellite line of sight （LOS） area. Determination of WUL will help the system to provide accurate and reliable integrity information, such as SISA, SISMA and integrity flag （IF） to users, which is very critical to improve the reliability and availability of the navigation system. Basic principle and computation flow of two WUL algorithms, namely, critical circle method and grid search-based method, are presented. Computation results are analyzed and compared to show the performance of the two algorithms. Finally, conclusions are drawn based on the evaluation of global and regional integrity monitoring.