Line spectrum nonstationary and Dopplerlet range estimation of a moving vessel

The line spectrum of moving vessel radiated-noise is usually used to improve sonar detection performance ("line components" occurring at discrete frequecies in a spectrum is called "line spectrum"). A new method to estimate range and speed of a moving vessel by a nonstationary characteristics of line spectrum is presented. And four spectrogram examples of the moving vessel radiated-noise are provided, which show some time-frequency characteristics including line spectrum nonstationary, the variance of moving state reflecting by line spectrum nonstationary and the interference patterns caused by interactions between the radiated-noise and the acoustic channel. It indicates there are two kinds of characteristics containing the information of range and speed, the Doppler line spectrum and the interference pattern. Dopplerlet transform and matching pursuit are used to estimate range and speed. The result of the computer simulation shows the method is practicable and effective. Moreover, the range and speed estimation of the real underwater data on the sea conform to the on site results.