Radial velocity estimation of moving target based on maximum likelihood estimation

Abstract

For conventional multichannel synthetic aperture radar (SAR) systems, the pulse repetition frequency is greater than the azimuth Doppler bandwidth. Therefore, each receive channel can obtain unambiguous SAR image and the moving target usually overlaps with no more than one clutter. However, for high-resolution wide-swath (HRWS) SAR systems, the PRF is usually much less than the Doppler bandwidth and thus the moving target may overlap with quite a few clutters, which will severely affect the estimation of the radial velocity of the moving target. A novel radial velocity estimation method based on maximum likelihood estimation (MLE) for HRWS SAR systems is presented. Even if the moving target overlaps with quite a few clutters, the proposed MLE method can still effectively estimate the radial velocity. In order to reduce the computational load, the proposed method transforms the multi-dimensional spectral peak searching of MLE into one-dimensional peak searching and reduces the times of matrix inversion by a block matrix method. Theoretical analysis and experiments demonstrate the feasibility of the proposed method.