修正主模抑制稳健自适应波束形成算法

Modified Dominant Mode Rejection Robust Adaptive Beamforming Algorithm

针对自适应波束形成器在少快拍和波束指向角度失配情况下性能严重下降的问题,该文提出一种基于修正协方差矩阵的稳健主模抑制算法。算法提出利用修正协方差矩阵估计主模成分,进而重构出数据协方差矩阵,同时利用其特征向量向期望信号导引向量的投影来确定信号子空间维数。为提高算法在低信噪比情况下的性能,提出利用信号区域积分得到正定矩阵,以其主特征向量对信号子空间进行扩充,再将导引向量向信号子空间进行投影得到修正的导引向量。最终利用重构协方差矩阵及修正导引向量得到最优权值。理论分析和仿真实验验证了所提算法的有效性和稳健性。

In order to solve the problem of adaptive beamformer performance degradation due to few snapshots and mainlobe angle mismatch, a robust dominant mode rejection adaptive beamforming algorithm based on modified covariance matrix is proposed. The algorithm employs modified covariance matrix to estimate dominant mode component and reconstructs covariance matrix. Then, the signal subspace is obtained by projecting the steering vector of the desired signal onto eigenvector of the reconstructed covariance matrix, for enhancing the performance of algorithm at low SNR, the algorithm uses the principal eigenvector of a positive define matrix which integrates the desired signal region to modify signal subspace, thus calibrated steering vector of the desired signal is obtained by projecting the presumed steering vector onto the modified signal subspace. Finally, the optimal weight is obtained from the reconstructed covariance matrix and the calibrated steering vector. Theoretical analysis and simulation show the effectiveness and robustness of the proposed algorithm.