中文说明：
本文作的工作是利用信号仿真器仿真GPS数字中频信号，并借助这些仿真信
号完成对GPS信号的捕获和跟踪性能的研究。
English Description：
This work is to use the digital intermediate frequency signal simulation of GPS signal simulator, and the simulation with the help of these letter no. _ complete study of GPS signal capturing and tracking performance.