Imaging and Parameter Estimation of Fast-Moving Targets With Single-Antenna SAR

This letter proposes a novel algorithm for focusing moving targets with fast cross-track velocities and estimating their motion parameters with single-antenna synthetic aperture radar. The spectrum of a fast-moving target contains the Doppler ambiguity and the third-order phase error. Hough transform is utilized to estimate the slope of the range walk trajectory, from which the cross-track velocity is obtained and the Doppler ambiguity problem is solved. Then, polynomial Fourier transform is adopted to estimate the second- and third-order Doppler parameters of the moving target. By estimating and compensating for the third-order phase error, the imaging resolution of the fast-moving target is improved and the motion parameters, including the cross-track acceleration, are correctly estimated. Both simulated and real data processing results are provided to demonstrate the effectiveness of the proposed algorithm.