Underwater target detection based on fourth-order cumulant beamforming

Abstract

Due to the complicated influences of the sea environment, how to obtain target echo data with high SRR (Signal-to-Reverberation Ratio) (SNR: Signal-to-Noise Ratio) is the key issue for improving the capacity of underwater targets detection. Based on the array signal processing, this paper presents a robust and highresolution fourth-order cumulant beamforming method based on the characteristics of array aperture expansion of fourth order cumulant, and DOA (Direction of Arrival) estimation of target is achieved by forming a narrow spatial beam. For a wideband acoustic system, the fourth-order cumulant beamforming method is extended to the DOA estimation of wideband LFM signals, combined with fractional Fourier transform (FRFT). Reverberation and noise are filtered out in the FRFT domain to further improve the SRR and SNR of the target echo. Simulation and data processing results of active sonar target detection verify the effectiveness of the research methods.