发射信号不完善性对卫星导航系统内及系统间干扰的影响分析

研究了3种典型的卫星发射信号不完善性——载波泄漏、互调失真和杂散辐射对于卫星导航信号的接收所带来的干扰,通过信号建模以及谱分离系数、码跟踪谱灵敏度系数和等效载噪比的解析计算对干扰效果进行量化分析;针对GPS和Galileo系统L1/E1频段的信号进行了多层次的仿真计算,给出了综合考虑噪声、信号损耗、外源干扰、GNSS系统内和系统间干扰,以及3种信号不完善性单独作用、两两组合和综合作用下的结果,其中对于GPS L1C/A短码考虑了电文调制对线谱的影响。结果表明,当总的不完善干扰功率水平达到一定程度后,其对接收机信号捕获跟踪和解调的影响大于系统间干扰,不能忽略。

Impact Analysis of GNSS Signal Imperfections on Intersystem and Intrasystem Interference

Three types of satellite signal imperfection——incompletely suppressed carrier,intermodulation distortion and spurious emissions——and their interference on GNSS signal receiving are studied in this paper.The interference effects are quantitatively analyzed based on signal modeling and analytical computation of the spectral separation coefficient(SSC),the code tracking SSC(CT-SSC) and the effective carrier to noise ratio.Using the signals in GPS L1 and Galileo E1 band,the effects of the noise,the signal processing loss,the external interference,GNSS intrasystem interference and intersystem interference in the presence of different combination of the three types of signal imperfection are calculated.The results show that when the total signal imperfection interference reaches a certain power level,it will have more impacts on signal acquisition,carrier tracking and dada demodulation than intersystem interference.This analysis provides a reference for the specification of the satellite signal quality.