Estimation of propeller shaft rate and vessel classification in multipath environment

A problem of interest in a passive sonar system is the demodulation of the wide-band signal received from a vessel's propeller shaft blades. The signal emitted by the vessel becomes a multipath channel which could render erroneous classification of the vessel using the digitized acoustic signal. A new approach is introduced to determine the propeller shaft rate and the number of propeller blades. The cyclostationarity behavior of the acoustic signals from a vessel is exploited to achieve the desired tasks.