空间信号精度的算法设计与实验分析

Calculation and Analysis of Signal-in-Space Accuracy

导航系统的完好性关系到用户的安全问题,空间信号精度(SISA)是反映卫星导航系统完好性的重要指标之一。针对导航电文中的广播星历和钟差参数信息处理问题,设计了SISA参数计算方法;利用GPS和BDS系统中的实际数据,分析了不同轨道类型卫星SISA参数对空间信号误差的包络特性,并将导航电文中URA参数与SISA参数进行比较,验证了SISA参数计算方法。实验结果表明,SISA能够准确反映广播星历的空间信号精度,并能够对空间信号误差基本实现平均98%的包络能力;目前北斗广播星历中的URA参数不能够精确反映空间信号的精度,不同卫星的空间信号精度相差较大,SISA能够准确反映和包络北斗空间信号误差。

Integrity of satellite navigation system is critical to user＇s security. Signal-in-Space accuracy （SISA） is one of the important indicators reflecting the integrity parameters in satellite navigation and positioning system. This paper designs and discusses a method of SISA parameter calculation for the satellite orbit information and clock errors in the broadcast ephemeris, respectively. We utilize GPS＇s and BDS＇s navigation messages to analyze satellite＇s SISA envelope characteristic of spatial signal error of different types. The method is verified by comparing SISA with URA in the broadcast ephemeris. The results show that： SISA reflects the GPS signal accuracy more accurately than the value. And it can achieve nearly 98% envelope capacity for SISE. For BDS, SISA can accurately reflect and envelope SISE while URA parameter in broadcast ephemeris can＇t. SISA realize more than 99.9% envelope capacity in Compass.