随机相幅误差对舷侧阵MVDR波束形成器阵增益的影响

Array gain analysis of MVDR beamformer in the presence of amplitude and phase error

舷侧阵正常工作时,由于海洋环境比较复杂,以及每路水听器通道的传输特性不完全一致,使舷侧阵每一个水听器输出信号的相位和幅度叠加了一个随机误差。在作MVDR自适应波束形成时,该随机误差的存在将影响到基阵的阵增益,降低检测能力。仿真结果表明:幅度和相位误差的存在会降低MVDR波束形成器的阵增益,两类误差越大,阵增益就越小;输入信噪比越高,MVDR波数形成器的阵增益就越小。文中从统计学角度分析了随机相幅误差对协方差矩阵的影响,然后通过数值仿真得到阵增益的变化规律。

Flank arrays working under water inevitably face problems such as complex ocean environment and perturbations. Therefore hydrophone output contains random perturbations both in amplitude and phase, which affect the beam pattern and array gain in MVDR based beamforming. Simulation results show that phase and amplitude errors can reduce the gain of MVDR beamformer array, which become more severe at large errors and high SNR. This paper studies two cases. First, assume only phase error exists. An actual steering vector, which contains phase error, is introduced and the array gain analyzed. Then the same approach is used to analyze the case where only amplitude error exists.