A Wideband Lateral Multibeam Tiling Synthetic Aperture Method for High-Speed Side-Scan Sonar

Side-scan sonar technology plays an important role in seabed topographic exploration and mapping. However, the mainstream matched filtering technique does not fully utilize the bandwidth and the distance matching is susceptible to the Doppler effect, which limits the imaging effect and towing speed. In addition, the synthetic aperture method of radar is difficult to be adapted to sonar due to the transmission characteristics of acoustic waves in water. To address these issues, we propose a lateral multi-beam tiling synthetic aperture algorithm framework for linear array side-scan sonar (LMBT-SAS). The core idea is to improve long-range information acquisition capabilities through beam focusing, and indirectly increase the azimuth pulse repetition rate to serve synthetic aperture processing to increase towing speed. To further improve image performance and towing speed, within this framework, we also proposed some specific technical means. Including short-time Fourier frequency domain beamforming with speed compensation, beam tiling with pseudo pulse repetition, distance-dependent beam weight allocation mechanism and two-stage migration correction. The simulation results and lake test data imaging results demonstrate the effectiveness of the proposed LMBT-SAS algorithm, with a performance of 250 meters of transverse scanning distance and 12 knots of towing speed at 400 KHz signal.