Autofocus of wide azimuth angle SAR images by contrast optimisation

The authors address the problem of focusing synthetic aperture radar (SAR) images for wide azimuth angle of observation. In these applications a second order polynomial approximation does not accurately fit the phase term due to the platform motion. Therefore, image focusing requires higher order polynomial approximation. The authors propose a simple and effective autofocusing method based on the contrast optimisation of the image. They also present and discuss simulation results to illustrate the effectiveness of the method.