Estimation of propeller shaft rate in multipath environment using Nevanlinna-Pick interpolation

A problem of interest in passive sonar system is the demodulation of the wide-band signal received from a propeller shaft blades of a vessel. The signal emitted by the vessel undergoes multipath channel that render erroneous classification of the vessel using the digitized acoustic signal. In this paper, a new approach is introduced to determine the propeller shaft rate and the number of propeller blades. The spectral behavior of acoustic signals from a vessel is exploited to achieve the desired tasks using Nevanlinna-Pick interpolation technique.