一种改进的空间信号完好性监测算法

针对Galileo系统空间信号完好性监测方案中两项关键技术点做出改进：1)提出改进临界圆法,从坐标系转换角度解决最坏用户位置方位角转换的复杂度问题；2)引入“截尾概率包络”概念,改善原模型对非零均值空间信号误差值高斯分布的过分包络问题。最后在无故障、阶跃类故障、斜坡类故障三种模式下,对比分析改进方案前后系统的完好性性能。结果表明,完好性阈值对实时空间信号误差估计值的平均包络紧度由3.89米改善至2.62米,对斜坡类故障的告警更加及时。

An Improved Signal-in-Space Integrity Monitoring Algorithm

To improve the algorithm of two key technologies in the Galileo Signal-in-Space integrity monitoring system, an improved critical circle method and a censored probability envelope model were proposed for the determination of the worst user location and enveloping the Signal-in-Space Error respectively. The improved critical circle method could obtain accuracy WUL directly by coordinate conversion to simplify purely geometric derivation. The censored probability envelope model solved the over-bound problem by using a new envelop concept for the SISE distribution with non-zero mean. Finally, simulations were conducted to compare the integrity performance of the improved algorithm with the original one in fault-free, step failure and slope failure modes. The results show that the integrity threshold envelope tightness improves from 3.89 meters to 2.62 meters and system alarm more timely than the original algorithm in the slope failure mode.