Autofocus: The key to a high SAR resolution

Uncompensated phase errors lead to a significant quality degradation of images obtained with a synthetic aperture radar (SAR). In the paper, an efficient approach to the SAR autofocusing is proposed. The main idea of the method is the usage of independent local phase error estimates on short time intervals for an arbitrary phase error reconstruction. The residual phase error is retrieved via a double integration of the estimated time-series of the second derivative of the phase error. A high efficiency of the approach is confirmed by experimental results.