Efficient method for the translational motion compensation of inverse synthetic aperture radar imagery

A new method for estimating the motion parameters of a target from its step ped-frequency inverse synthetic aperture radar signature is developed, impl emented, and tested. The proposed method uses the phase of the target's ech o transfer function to focus the radar image while avoiding Fourier process ing. A focal-quality indicator is proposed that yields optimum motion-param eter estimates with the least number of computations. Complex analysis is e xploited to measure the slope of the phase more accurately by selecting reg ions of the target signature with a high signal-to-noise ratio. A weighted- least-squares approach optimizes the estimation process by grading the sele cted segments and assigning reliability weights. The Cramer-Rao bounds for lower limits on velocity and acceleration estimates are derived in the cont ext of weighted-least-squares complex analysis. The proposed method provide s higher accuracy and efficiency than conventional methods. (C) 2001 Societ y of Photo-Optical instrumentation Engineers.