Range estimation of continuous transmission FM (CTFM) sonar for a fast moving target

This paper proposes an extension of the CTFM approach to estimate range and velocity for a fast moving target. Traditional CTFM processing assumes a stationary or slow moving target. However, for a fast moving target, the Doppler shift creates distortions in the estimated range. We propose a method whereby multiple Doppler shift channels are applied and then we look for minimal variance across all Doppler channels. Also a direct path signal elimination algorithm is proposed.