This method constructs covariance matrix by utilizing data vectors in different range lines and projects phase error vector into noise sub-space which is formed by eigendecomposing the covariance matrix.

• 该方法利用不同距离单元的观测矢量构造协方差矩阵，然后通过对协方差矩阵特征分解得到噪声子空间，最后将相位误差矢量向噪声子空间投影来估计多普勒调频率。