Analysis And Application Of Ship Seismic Wave Signal Characteristics

In shallow water,when the frequency of ship radiated noise is lower than the cut-off frequency of normal wave,the underwater acoustic signal is seriously attenuated,and its propagation in the form of ship seismic wave through the seabed becomes a way of acoustic propagation.As a new type of physical field,the analysis and application of ship seismic wave are of great significance in the field of underwater acoustics.The detection and feature extraction of underwater target signal is the key of surface ships.Because the propagation channel of underwater target is very complex,it is difficult to detect weak signal under strong background noise interference,therefore,it is still necessary to explore a new method of surface ships detection.At the same time,the ship seismic signal in the low-frequency,low-frequency signal will affect the physiological and psychological aspects of sonar personnel,so it is necessary to study the objective law of frequency shift operation of ship seismic signal and auditory feature extraction method.The paper focuses on the characteristics of ship seismic wave and its application in surface ship detection and auditory feature extraction.Firstly,the polarization characteristic of ship seismic wave are analyzed,and the line spectrum polarization filtering algorithm of ship seismic wave is studied.The purpose of this paper is to improve the weak signal detection of surface ships under the interference of strong background noise,and to provide a new signal processing method for the long-distance detection of underwater target.Secondly,the modulation characteristic of ship seismic wave is analyzed.According to the low frequency characteristic of the envelope modulation signal of ship seismic wave,the psychoacoustic characteristic parameters of the frequency shift operation of the envelope modulation signal of ship seismic wave are studied.At the same time,according to the “rhythm” in listening ship seismic wave envelope modulation signal and considering the excellent detection performance of underwater acoustic listening processing,the research of auditory feature extraction is carried out.The purpose of this method is to provide technical support for the safety of sonar hearing.The main research contents and conclusions are as follows:1.Analysis and application of polarization characteristic of ship seismic wave signalIn the paper,the polarization characteristic of seismic line spectrum signal is analyzed,and the frequency domain polarization parameters suitable for the line spectrum signal are obtained through optimization.Then,the polarization filtering function is constructed.The line spectrum polarization filtering algorithm is realized by weighting the polarization characteristic spectrum of the line spectrum signal.The influencing factors of the polarization filtering function are analyzed.The fourth-order cumulant joint polarization filtering function and the multi-layer autocorrelation joint polarization filtering function are constructed.The simulation and experimental results show that the corresponding fourth-order cumulant polarization filtering algorithm and multiple autocorrelation polarization filtering algorithm overcome the problems of limited analysis points and low signal-to-noise ratio of ship seismic signal.The line spectrum polarization filtering algorithm can suppress the background noise interference and extract the line spectrum signal.The weak signal detection of ships under strong background noise interference is realized,which has a good application prospect for passive sonar signal processing and long-distance detection of underwater acoustic targets.2.Modulation characteristic analysis and auditory feature extraction of ship seismic wave signalIn the paper,the modulation characteristic of the ship seismic wave signal is analyzed.Aiming at the low frequency characteristic of the ship seismic wave envelope modulation signal,the frequency shift operation of the sonar is studied.The variation law of the psychoacoustic characteristic parameters of the ship seismic wave envelope modulation signal is given,which provides the theoretical basis and reference for the sonar to listen to the frequency shift operation.The feature extraction of the time-varying loudness of the envelope modulation signal of the ship seismic wave is studied.The results show that the time-varying loudness time-frequency map is better than the power spectrum time-frequency map.On the basis,the beat loudness variation characteristic is proposed.The simulation and experimental results show that the recognition rate of the change of beat loudness is higher than that of the steady-state loudness.In addition,in the research of the acoustic filter feature extraction of the ship seismic wave signal,it is found that the acoustic filter can be used to detect and extract the line spectrum signal of the ship seismic wave.Compared with the traditional line spectrum extraction method,the output signal-to-noise ratio of the line spectrum signal is improved.Finally,it is found that the cepstrum coefficient feature of equal bandwidth triangle filter has better robustness under low SNR.The psychoacoustic characteristic parameters of frequency shift processing based on ship seismic wave envelope modulation signal provides a new method for recognition of low frequency ship seismic wave,and ship seismic wave auditory feature parameters provides the same effect.