极浅海环境下时间分集MIMO声呐高分辨成像方法OA

In extremely shallow water environments with strong reverberation,traditional multiple-input multiple-output(MIMO)sonar is affected by cross-correlation interference from synchronous orthogonal waveforms.The high range sidelobes significantly raise the reverberation background,leading to severe performance degradation of adaptive beamforming algorithms.To solve this problem,this paper proposed a high-resolution imaging method for time-diversity MIMO sonar suitable for extremely shallow water environments.The method transmitted the same linear frequency modulation signals sequentially through a time-division mechanism and separated echo signals in the time domain by using pulse repetition intervals,thus eliminating cross-correlation interference.Combined with time-domain truncation and data reconstruction,an equivalent uniform virtual linear array with doubled aperture was constructed,which fully retained the high angular resolution of the MIMO system.Simulation results show that the proposed method effectively suppresses range sidelobes under a strong reverberation background with a signal-to-reverberation ratio as low as-20 dB and fully exerts the adaptive filtering capability of the minimum variance distortionless response(MVDR)algorithm.Compared with traditional orthogonal MIMO sonar,its-3 dB main lobe width,side lobe level,and integration side lobe rate are significantly optimized,providing a feasible scheme for high-resolution imaging of small targets in extremely shallow water that takes into account both virtual aperture and strong anti-interference ability.