中文说明：
本程序使用matlab仿真exprit算法并且可以通过前项平滑技术计算相关信号的方向，解决了exprit不能测相关信号方向的问题（加入了每一步的注释简单易懂）。
English Description：
This program uses MATLAB to simulate the exprit algorithm, and can calculate the direction of the correlation signal through the preceding smoothing technology, which solves the problem that exprit cannot measure the direction of the correlation signal (the notes of each step are added, which is easy to understand)