Improving Sidescan Sonar Performance Using Array Upsampling Beamforming Synthetic Aperture

Sidescan sonar technology plays an important role in seabed topography detection and mapping, but the performance of mainstream matched filter technology in long-distance image and towing speed limits its application scenarios. In addition, due to the slow propagation speed of sound waves in water, the synthetic aperture method in radar is difficult to adapt directly to sonar. To address these problems, a synthetic aperture algorithm framework for sidescan sonar with array upsampling beamforming is proposed (AUB-SAS). Firstly, the array element spacing is reduced by upsampling the array element to facilitate beamforming, and the long-distance information acquisition capability is improved by beam focusing. Secondly, the calculated multi-beam is used for synthetic aperture processing to make up for the low pulse repetition rate caused by the slow sound speed, thereby increasing the towing speed. In addition, the short-time Fourier transform with high resolution in the lateral direction and the motion compensation in the azimuth direction are derived, which further improve the imaging quality. The imaging results of lake test data prove the effectiveness of the proposed algorithm, achieving a lateral detection distance of 250 meters while the towing speed reaches 9 knots, and the imaging quality is significantly better than the traditional method.