GPS 和 Galileo 空间信号仿真及分析

介绍和详细分析了GPS和Galileo的空间信号。将Galileo空间信号结构及特性与GPS进行了比较,对接收机接收天线接收的射频信号进行下变频并予以分析。为避免信号混叠,仿真中先采用带通滤波器对射频信号进行滤波,然后采用过采样(过采样因子等于8)进行下变频处理。GPS和Galileo信号通过功率归一化加上高斯白噪声产生。对GPS采用的C/A码和Galileo采用的BOC(1,1)码进行比较,发现后者的中心波峰较窄,尽管这一特点使接收机的跟踪处理更为复杂,但提供了较好的接收性能,尤其在多路效应情况下也更为有效。仿真结果为GPS/Galileo双频软件接收机捕获和跟踪算法设计提供了很好的理论基础。

Simulation and analysis of GPS and Galileo signals in space

The space signals of GPS and Galileo were introduced and analysed.Galileo signal structure and properties were presented compared with GPS signals.Down-conversion processing of the radio-frequency signal received by the antenna was made and analysed.The signal is down-converted through digital decimation(over-sampling factor is equal to eight)of a properly filtered signal to avoid aliasing between replicas in simulation.The GPS and Galileo signals are generated through power normalizing and white Gaussian noise(AWGN).A comparison between C/A code and BOC(1,1)code was provided,and the central peak was narrower in the second case.This feature can provide better performance;and BOC(n,m)is more efficient in the multi-path case,although a higher complexity for tracking process was needed.The simulation results provide important theoretical foundation for the acquisition and tracking of GPS/Galileo duel-frequency software receiver.