Enhancement of acoustic field aberration for underwater forward detection with experimental verification

When an object crosses the source-receiver line, a weak acoustic field aberration is produced. However, it is often overwhelmed by the fluctuation of direct blast. A principal component analysis of stable portion of beam output on vertical receiver array is proposed to enhance the field aberration for forward detection. A lake experiment utilized a vertical receiver array spanning the water column was conducted. A 10 kHz pulse was transmitted successively, and the field aberration caused by the forward scattering of the crossing object was observed. The beam output waveform at the horizontal direction is processed with the proposed method, and the field aberration about 10dB above the background acoustic field is achieved, while the maximum aberration is only about 2dB above the background field before processing.