说明：  利用Matlab生成GPS C/A 码的基带信号。 （1）产生卫星PRN 号码为“5”的一组C/A 码； （2）循环生成25 页的导航数据，GPS 时间可填入一固定的已知数值； （3）生成C/A 码扩频信号，每个C/A 码码片给出4 个采样数据； （4）基带信号采用方波信号，电平为0 和1，占空比为50 ％， 不加入噪声，进一步生成某个特定的中频信号
(The baseband signal is generated using Matlab GPS C/A code. (1) generate satellite PRN number " 5" is a set of C/A code (2) loop generates 25 navigation data, GPS time can be filled with a fixed known value (3) generated C/A code spread spectrum signals, each C/A code chip sample data is given 4 (4) a baseband signal using a square wave signal with a level of 0 and a duty cycle of 50 , the noise was not added, and further generates a a specific frequency signal)