Classification of ships using underwater radiated noise
Concentrating mainly on the signal processing and physical models behind the algorithms used to classify ships by their underwater-radiated noise, the physical model for cavitation is expanded to include the losses by acoustical radiation and the heat transfer from the vapor to the fluid. The resulting equation allows one to find the characteristics of cavitation through simulation. Five algorithms for estimating the propeller speed have been found. The performance of the three most promising ones are judged with respect to the ratio of the expected value to the variance of the estimator. A complete Bayes hypothesis test on second-order autoregressive power density spectrum poles are then described for determining the kind of propulsion a vessel uses. The nature of gearbox noise is described, and the cepstrum is proposed as an algorithm to detect this kind of noise.