Abstract: The SOund NAvigation and Ranging (SONAR) is an underwater sound propagation technique used for navigation, communication or detection of objects on or under the surface of the water. The objects may be submarines, vessels etc. It involves the use of frequencies from very low or infrasonic range to extremely high or ultrasonic range. Proper design of a SONAR system requires accurate detection of the signals. Here, tonal features of the received signal are analyzed based on the signal detection theory. Using filtering and several comparison techniques, the targets can be detected and this can be simulated via variables using MATLAB. This paper attempts to design an algorithm for range estimation and target classification using Passive SONAR. The hardware implementation has a wide arena of applications mainly in the defence sector.

Keywords: Acoustic Propagation Loss, Least Mean Square Adaptive Filter, Energy Entropy, Short Time Energy, Zero Crossing Rate, Spectral RollOff, Spectral Centroid, Spectral Flux, Mean, Standard Deviation.