GNSS射频前端的多频信号兼容采样

Compatibility of multi-frequency signal sampling for GNSS RF front-end

针对不同频段GNSS信号存在的频率冲突问题,提出一种射频前端多频信号的采样频率兼容算法。分析了GNSS接收机射频前端的结构体制,指出射频直接采样数字化结构有利于同一射频前端实现多频信号的接收。在此结构基础上,考虑到多频信号采样频率兼容,采样后信号不发生混叠,以及实际工作环境的要求,提出一种计算多频段GNSS信号兼容采样频率的处理方法。利用该方法对GPS的L1、L2C和E5a信号的兼容采样进行仿真,结果表明,涉及到长码的采样兼容时,较小的采样频率对接收机的系统设计是有利的。

A sampling frequency compatibility algorithm for multi signals in radio frequency （RF） front-end is put forward to address the conflict problem among GNSS signals with different frequencies.The structures of RF front-end in the GNSS receivers are analyzed,which shows that the RF direct digitalization structure based on bandpass sampling is suitable for multi-band GNSS software receivers.Utilizing this structure,a sampling processing method for multi-band GNSS RF signals is put forward considering the compatibility of multi-band sampling frequencies,no signals aliasing after sampling,and the requirements of actual working environment.The simulations are made by applying this algorithm to achieve the compatible sampling of GPS L1,L2C and Galileo E5a,and the results show that the lower sampling frequency is beneficial to the system design of receivers when involved with long-code sampling compatibility.