Modified Range-Doppler imaging method for the high squint SAR

In this paper, a modified Range-Doppler (RD) algorithm with the Keystone Transform and the rank-deficient Capon is proposed for the shorter Synthetic Aperture Radar (SAR) imaging in the high squint mode. With the decrease of the aperture time under the squint mode, the linear range-walk becomes the dominant part of the range migration. The Keystone Transform is well suitable for removal of the range walk. In order to achieve higher resolution in the azimuth domain with the shorter SAR, the rank-deficient Capon which is an efficient non-diagonal loading spectral estimation based on rank-deficient sample covariance matrix is adopted. Simulation results can obtain the finer SAR images of the proposed approaches.