Research On Moving Target Detection Based On Doppler Characteristic

Due to the development of underwater target detection technology,sonar waveform has also evolved from a single sinusoidal pulse into many forms such as CW,FM,phase encoding and pulse combination.Each signal in anti-reverb,anti-multipath,anti-Doppler shift,reduce the sidelobe response,improve the resolution and other aspects of the characteristics are different.When the velocity of the moving target is unknown,the influence of Doppler shift will cause the target echo to be mismatched with the sample so reducing the ranging accuracy and detection performance.And because the output of the matched filter has higher Distance sidelobes and presence of Doppler spectrum leaks,all of which can lead to degraded sonar system detection performance.In this paper,the moving target detection method based on low sidelobe Doppler filter bank and the moving target detection method based on the full phase spectrum analysis are studied in the case that the target echo signal exceeds the Doppler tolerance.First of all,analyze the performance of signal waveform in moving target detection.The temporal resolution,frequency shift resolution and Doppler tolerance of CW pulse,LFM,HFM and M sequences are analyzed by using signal fuzzy graphs.Secondly,the moving target detection method based on the low sidelobe Doppler filter bank is studied.The moving target is processed by the detection method of Doppler filter bank,and then the sidelobe suppression is implemented for the problem that the mainlobe of the weak target is submerged due to the high sidelobe,including the direct windowing weighting method,IRSL method and deconvoluted side lobe suppression method.Finally,several algorithms were simulated and sea trial data processing.Finally,aiming at the problem that the spectrum leakage may cause the moving target to be lost,The full phase spectrum analysis is studied.Compared with the traditional FFT algorithm,the all-phase FFT has excellent performance in suppressing spectrum leakage,which is beneficial to distinguish the weak signal spectrum from the leakage spectrum.Especially under the strong noise interference,the weak signal spectrum can be achieved Noise submerged purposes,several algorithms were simulated and sea trial data processing.