Improved Keystone Transform Algorithm For Paired Echoes Focusing of SAR Vibrating Targets

Paired echoes are the typical Doppler characteristics of vibrating targets in high resolution synthetic aperture radar (SAR). Conventional imaging algorithms produce smeared paired echoes which is not conductive to the analysis of vibrating parameters. A paired echoes focusing algorithm for vibrating targets is proposed. On the basis of the analytic formula derivation in 2-D frequency domain for vibrating targets, Keystone transform is employed to perform migration correction. Then the quadratic phase error is compensated in the Range-Doppler domain. Finally, the vibrating targets and the stationary targets can be well focused contemporaneously. The proposed algorithm needs no prior knowledge of vibrating targets, so it can be used for the imaging of multiple targets at different vibrating state. The simulation results validate the effectiveness of the proposed algorithm.