基于铱星增强的GPS系统RAIM性能

为评估基于低轨卫星增强的导航系统RAIM性能,建立了基于铱星增强的GPS(以下简称为iGPS)系统的伪距观测方程,估算出该系统用户距离均方根误差,并在此基础上分析了该系统RAIM性能。结果表明,铱星的增强不仅可以显著改善系统GDOP及HDOP值,而且显著提高了故障检测和识别概率,可检测的最小故障偏差从20 m降到10 m,可完全检测的最小故障偏差从80 m降到40 m,可识别及可完全识别的最小故障偏差也得到明显降低,为基于低轨卫星的导航增强系统设计提供了参考。

Receiver autonomous integrity monitoring in iridium-augmented GPS

iGPS is a system that integrates global positioning system(GPS)and low-earth-orbit iridium satellites, its basic goal is to enhance GPS positioning and timing performance. In addition, augmentation of GPS with iridium satellites also guarantees signal redundancy, which enables receiver autonomous integrity monitoring(RAIM). The pseudo range measurement equation of iGPS was established and calculation was made of the user equivalent range error(UERE ), which is approximately 3 meters. Then the performance of RAIM was studied in iGPS. The analysis based on MATLAB simulation proves that the augmentation of Iridium not only improves the GDOP and HDOP values, but also the rates of fault detection and identification.