Robust detection of underwater targets using a nonlinear energy tracker

The use of sonar systems is widely applied to detection of underwater targets. Conventional detection methods estimate the Doppler characteristics of an underwater target by processing the received signal in the frequency domain, for example by the use of the discrete Fourier transform and filter bank structures. We propose a robust scheme for estimation of the Doppler characteristics of an underwater target by employing nonlinear processes. Since the proposed method is processed in the time domain, it can significantly reduce the computational complexity. The proposed scheme can also be used for estimation of the velocity and distance of the target. The performance of the proposed scheme is analyzed and verified by computer simulation.