Pages: 114-128

Abstract

The sonar is actually a radar which is used on or under the surface of the water and uses sound ‎waves instead of radio waves to survey the environment. Detection and classification of marine ‎vessels based on their acoustic radiated noise is of great importance in sonar systems. The non-‎static nature of the radiated noise of marine vessels and its dependency on the propagation ‎channel, the variability of some of its parameters, and the difficulties in the simulation of this ‎noise, make detection algorithms using a limited number of real data with a low diversity and ‎or simulated training data to be not adequately valid. The present study aims to provide a new ‎algorithm for the separation of target signals received in the form of convolutive mixture. For ‎this purpose, a time-frequency window is designed that reconstructs an approximation of the ‎target signal in the frequency domain. The cosine of the angle between two vectors is equal to ‎the cosine of a parameter, called Hermitian angle between the two vectors. The Hermitian angle ‎between two complex vectors remains unchanged if the two vectors are multiplied in a complex ‎scalar. In the present study, this property is used to design a window for the separation of ‎sources mixed convolutively. The advantage of this window over other detection methods is ‎that there is no need for primary information on the geometric location of sources and ‎hydrophones‎‎‎‎.