An Underwater Wideband Multi-Highlight Active Target Velocity Estimation Method Based on Cepstrum and Matched Filter

In this paper, a multi-highlight target echo model is investigated, and the target is considered to be of a constant relative velocity to the sonar. The echo is usually equivalent to the superposition of reflections from single highlight. Due to the relative motion of the active sonar and the target, the echo is stretched or compressed. Moreover, noise and reverberation are existed in the underwater environment. All of the above degrade the performance of the target velocity estimation. As a nonlinear signal operation method, cepstrum can change the convolution operation in time domain into the summation operation in the cepstrum domain. Based on the good performance of cepstrum operation in detecting periodic signals, a cepstrum-based target velocity estimation method is proposed. In this method, a combined pulse signal is transmitted, and the received echo is successively subjected to Matched Filter and cepstrum operation, the position of the peak in the cepstrum domain is searched to estimate the velocity of the target. Simulation results demonstrated that the proposed method can estimate the target velocity precisely at low signal-to-noise ratio using small computational effort.