软件GPS接收机信号搜索捕获的仿真实验研究

Study on Simulation of Signal Search and Acquisition in Software GPS Receiver

信号搜索捕获是基于软件无线电(SDR)技术的软件GPS接收机(SGR)的重要组成部分,同时也影响软件GPS接收机的工作性能指标。通过特定设计的硬件实验装置获取了真实GPS数字中频信号,利用Matlab分别在时域和频域范围对信号搜索捕获进行了算法仿真,同时对GPS信号中C/A码产生也进行了仿真。根据信号搜索捕获理论结合仿真试验结果,对时/频域两类处理方法进行了分析和比较,认为基于FFT的频域搜索捕获方法是软件GPS接收机工程实现的合理选择。

Signal search and acquisition is an important part of software GPS receiver based on software definition radio, and also makes an influence on the working performance of it. After the real GPS digital IF signal was obtained by means of a special experimental set, Matlab＇s simulation of signal search and acquisition is made in time-field and frequency-field respectively, meanwhile, the generation of GPS C/A code is also simulated. With the theory of signal search and acquisition, according to the result data of simulation experiment, methods of time-field and frequency-field are compared and analyzed. Method of FFT in frequency-field is the wise choice of engineering realizing of software GPS receiver.