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

The acoustic environment of the continental shelf slope waveguide 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.