DOA估计：最大熵算法、最小模算法、最小方差算法。输入： 快拍数据协方差矩阵R，观察范围内各方向导向矢量，三维矩阵phiyz。输出：最小方差谱估计矩阵P。-DOA Estimation: maximum entropy algorithm, the minimum norm algorithm, the minimum variance algorithm. Input: snapshot of the data covariance matrix R, the steering vector