Imaging and Parameter Estimating for Fast Moving Targets in Airborne SAR

A novel algorithm is presented to image fast moving targets and estimate moving parameters in single-antenna synthetic aperture radar, in which phase information is extracted by a proposed maximum amplitude extraction algorithm, and the Doppler parameters of moving targets are estimated by combining the fractional Fourier transform and an adaptive and iterative ambiguous number estimation algorithm. The range curve and walk can be corrected simultaneously with the estimated Doppler parameters. After azimuth compression, the shortest distance is estimated in a focused image to obtain the accurate moving parameters. Our simulations demonstrate that high-precision estimation and robust performance can be achieved when a large range curve and walk caused by fast moving targets exist, even in low-signal-to-noise-ratio cases. Comparisons with state-of-the-art algorithms also illustrate the advantages of the proposed algorithm.