陆架斜坡海域水平阵波束形成阵增益仿真分析

Array gain of a horizontal uniform linear array in the continental shelf slope

陆架斜坡海域海洋环境复杂多变,水下声基阵在该海域实际应用时,阵元接收信号的幅度和相位会发生畸变,阵元间信号相关性减弱,会带来波束形成器阵增益的严重下降,进而导致声呐探测性能的损失.目前陆架斜坡海域不同波束形成器阵增益的研究较少见,本文在各向同性噪声场假设条件下,针对陆架斜坡海域上坡波导环境中水平阵的常规波束形成器(CBF)、最小方差无失真响应波束形成器(MVDR-BF)和特征值波束形成器(EBF)的阵增益进行仿真研究.结果表明:(1)CBF和MVDR-BF的阵增益均与声场水平纵向相关性有关,当水平阵的阵元个数超过一定值时,两种波束形成器的阵增益均不再随着阵元个数的增加而增大;(2)EBF的阵增益由信号协方差矩阵最大特征值与其所有特征值之和的比值决定;(3)当接收数据信噪比为.10 dB时,MVDR-BF的阵增益高于CBF,但两者均小于EBF的阵增益.

The acoustic environment of the continental shelf slope wavegnide is very complex. For an underwater acoustic array in this area, the amplitude and phase of the received signals will be distortional, which leads to the signal correlation attenuation and the array gain of the beamformer decreasing. However, there has been little work on the array gains of different beamformers in the acoustic propagation environment of the continental shelf slope. In this paper, a horizontal uniform linear array （ULA） receiving signals from a shallow source is considered in the upslope propagation condition and the array gains of conventional beamformer （CBF）, minimum variance distortionless response （MVDR-BF） and eigenvalue beamformer （EBF） are presented. The results of numerical simulations show that： 1） the array gain of CBF and MVDR-BF is related to the horizontal longitudinal correlation of the sound field and will not increase anymore when the number of the hydrophone exceeds a certain value. 2） The array gain of EBF is determined by the ratio of the maximum eigenvalue to the sum of all eigenvalues of the signal covariance matrix. 3） The array gain of MVDR-BF is larger than that of CBF when the signal-to-noise ratio of the receive data is -10 dB, but both of them are smaller than the array gain of EBF.