Active Sonar Target Detection Technology Of Shallow Sea Dynamic Platform

In active sonar,"reverberation" is one of the main sources of interference,especially when the active sonar works in shallow sea environment,the sonar will be subject to more serious interface reverberation.Therefore,how to reduce the impact of reverberation on target detection estimation has been a key issue in the field of active sonar design.In this paper,two aspects of active sonar transmit signal waveform design and parameter optimization,and anti-reverberation target detection methods are investigated respectively.Firstly,the anti-aliasing performance of single-frequency pulse signals,linear FM pulse signals,sinusoidal FM pulse signals,periodic repetitive signals,Costas signals and other signals are compared for the waveform design and parameter optimization of the transmit signal,and the influence of the selection of each parameter,such as the center frequency and bandwidth of the signal,on the received signal-to-aliasing ratio under the influence of the channel of the moving platform is analyzed to determine the active sonar waveform design principles.Secondly,beam formation and matched filtering are performed on the received signal of the active sonar base array,and the anti-reverberation performance of the conventional signal processing methods of the active sonar in the beam domain,Doppler domain and time delay domain is analyzed.For the problem that the detection effect of the target detection method based on beamforming and matched filtering is not good when the signal mixing ratio is low,the spatial adaptive processing method for the rearranged received data is studied.And based on the reverberant space-time characteristics of the dynamic platform,the principle of optimal space-time processing is analyzed,and a dimensionality reduction algorithm with less operations is proposed.The research of this paper shows that in waveform design and parameter optimization,the linear FM pulse signal has good anti-reverberation performance at low Doppler and Costas signal has good anti-reverberation performance at high Doppler,and the influence of signal parameter selection on the received signal-mixing ratio is greatly influenced by the transmission channel,and the parameters need to be adjusted according to the a priori information of the channel to adapt to different environments.In terms of signal processing,the detection method based on beamforming and matched filtering has better detection performance than the detection method based on spatial adaptive processing in low signal mixing ratio environment,and the amount of spatial adaptive processing operations can be significantly reduced by the dimensionality reduction algorithm.