Joint time-frequency distribution analysis of ship radiated transient noise

The transient noise of ship has the features of large energy, short time duration and frequent appearance. Such features affect the operation performance of sonar, and can be detected by a hostile sonar system. Researching the feature of underwater radiated noise is helpful to provide guidance for handling with the transient noise of ship. Traditional analytical method of transient noise is described only in time domain or frequency domain, and the accuracy of the obtained time variation characteristic is worse. Based on the reasons mentioned above, the Wigner-Will distribution and Empirical Mode Decomposition are combined in this paper, and the advantage of each method can be fully used, and the analysis of ship transient noise realized. The simulation and the experimental research demonstrate that the proposed method can remove the quadratic term disturbance of the Wigner-Will distribution, and it also provides a guarantee of the accuracy of the transient noise time variation characteristic. The proposed method is utilized to analyze typical transient noise of ships. According to the mechanism of transient noise, the results demonstrates that the proposed method can acquire the time-frequency characteristic of transient noise efficiently, and it has application significance in engineering.