在实际应用环境中,信源和阵列传感器等存在误差,假设期望信号的导向矢量与真实信源导向矢量的失配会导致阵列波束形成器把期望信号当作干扰来加以抑制。针对信号匹配误差导致自适应波束形成性能下降的问题,提出了一种基于空时二维协方差矩阵修正的波束形成算法,利用空时结构对宽带幅相误差校正的特性,对空时二维协方差矩阵进行重构,并对修正协方差矩阵进行特征值分解,分离出信号加干扰子空间,将失配导向矢量投影可使期望信号与噪声子空间严格正交,最后求解算法最优权值。算法有效改善了波束形成的输出信噪比,计算机仿真验证了理论分析的正确性和算法的稳健性。

In practical applications, there are errors in the source and array sensors, etc. It is assumed that the mismatch between the steering vector of the desired signal and the true steering vector will cause the array beamformer to suppress the desired signal. To solve this problem, a beamforming algorithm based on space-time two-dimensional covariance matrix correction is proposed. The space-time structure is used to correct the characteristics of wide-band amplitude and phase error. The covariance matrix is reconstructed, and the estimated interference subspace is updated by eigenvalue decomposition. The mismatched steering vector is projected into the updated subspace so that the desired signal is strictly orthogonal to the noise subspace, and finally the optimal weight of the algorithm is solved. the output signal-to-noise ratio of beamforming is improved effectively. The correctness of the theoretical analysis and the robustness of the algorithm are also verified by the computer simulation.

TN957.51

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