Target Velocity Estimation in Synthetic Aperture Radars Using the Mellin Matched Filter

Abstract

Construction of the radar image and estimation of the velocity of a moving target in synthetic aperture radars (SAR) is one of the key problems of the radar theory. The range cell migration (RCM) is a cause for the low quality of the radar images in this case. Traditional methods of RCM compensation, which are successfully used to construct radar images of stationary objects, do not provide the required quality when used in processing of signals of a moving target. Algorithms for solving this problem are currently known. However, most of the proposed algorithms use optimization procedures for estimating unknown parameters. This greatly complicates their practical implementation. An exception from these algorithms is the LvD-algorithm, which is based on double application of the Keystone transform (KT). The LvD-algorithm does not use procedures for searching of estimates, because it constructs the radar image of a moving target in the coordinates "longitudinal speed - transverse speed", which makes estimation of the target velocity very simple. The purpose of the presented paper is to develop an alternative algorithm for estimating the velocity vector and constructing radar images of a moving target in SAR without using optimization procedures. The algorithm is based on the use of the Mellin matched filter (MMF). Computer simulation showed that under the adopted in the article simulation scenario the proposed algorithm yields unbiased and efficient estimates of the components of the target velocity when the signal-to-noise ratio (SNR) is greater than minus 10 dB.