Research On Underwater Small Moving Target Detection Using Doppler-sensitive Signal Based On Acoustic Image Sequence

Based on the problems of underwater moving small target detection,this paper mainly discusses the use of Doppler sensitive signal as the transmitting signal waveform of sonar to distinguish zero Doppler interference from moving target and achieve the purpose of interference suppression;discusses the design of filter in Doppler domain to achieve the purpose of filtering interference;and combines multi-frame sonar image sequence and Hough transform technology to improve detection performance.The adaptability of common signal waveforms in moving target detection is analyzed.Compared with single-frequency rectangular pulse signal and linear frequency modulation signal,phase-coded signal can obtain both high time-delay resolution and frequency-shift resolution;there is no time-delay-frequency-shift coupling problem;and there is a blur map with the main peak approaching the pin shape.It is a Doppler sensitive signal,and anti-reverberation interference is very beneficial.Doppler sensitive signal is selected as the simulation signal waveform,and the range-azimuth-Doppler image is obtained by combining the matched filter banks with different frequency offsets and beamforming to detect moving targets.The interference suppression ability is discussed by comparing the results of Doppler tolerance signals with the same parameters.Through the actual data processing of the tank test,it is verified that the signal-to-interference ratio gain of 10 lgBT can be obtained by using M sequence as the transmitting signal waveform under the condition of high signal-to-noise ratio.To transmit periodic pulse signal,the transformation relationship between multi-frame echo signal model and Doppler domain is discussed.The interference suppression performances of various delay line cancellers and Doppler notch filters are analyzed.Hough transform technology is used to detect the trajectory of moving target in multi-frame sonar image sequence in order to improve the detection ability.The feasibility of the above method is verified by the data processing results of the actual pool test.