Research On Towing Active Sonar Signal Processing Algorithm And Multi-core DSP Implementation

The towed active sonar system overcomes the limitation of the size of the receiving array,and the variable depth of the receiving array allows the sonar to work at the most suitable depth,so it is widely used in the field of underwater acoustic detection.This article is aimed at the research of towed active sonar signal algorithm and it’s multi-core DSP implementation.Firstly,the algorithms related to towed active sonar are introduced.In terms of spatial signal processing,the design and implementation of a wideband frequency domain DFT beamformer under a vector receiving array are studied.In order to resolve the inconsistency of the main lobe widths of the subbands in the frequency domain DFT beamformer,the method of the constant beamwidth beamformer was studied.Aiming at the problem of Random strong interference in towed active sonar detection,low sidelobe beamforming and zero-notch beamforming is studied.In terms of signal processing in the time-frequency domain,in order to reduce the influence of reverberation,anti-reverberation method based on pre-whitening and Bivariate singular value decomposition is studied.Aiming at the target distance estimation requirements of active sonar,the matched filter of LFM signal and the method of adaptive matching filter in frequency domain are studied.The implementation process of frequency-domain fast sliding correlation algorithm is introduced.Aiming at the requirement of active sonar target speed estimation,the frequency estimation technology of CW signal is studied.The algorithm includes adaptive line spectrum enhancer and corresponding frequency domain batch processing technology,and a frequency estimation algorithm based on FFT interpolation.Finally,in order to compensate the delay estimation deviation caused by the relative motion of the target,a simple delay correction method was researched.Based on the research of towed active sonar signal processing technology,the towed active sonar signal processing software is designed and its implementation process on multi-core DSP C6678 is introduced.Firstly,according to the actual needs,the software framework of the multi-core signal processing system is constructed.Under this framework,the network communication module,multi-core data interaction module and signal processing module are designed and implemented.After that,each module of the towed active sonar signal processing software was tested and verified,including tests on the performance of the receiving array,data transmission,signal processing functions,and real-time load conditions of the DSP.Finally,the lake test is introduced,and the performance of the sonar is analyzed.