Extended PGA processing of high resolution airborne SAR imagery reconstructed via backprojection algorithm

This paper extends the classical phase gradient autofocus motion compensation methodology for imagery reconstructed via backprojection algorithm(BPA) in high resolution synthetic aperture radar(SAR). As the existence of the space variant defocus and range cell migration due to motion error in BPA imagery, traditional autofocus methods usually can not be applied directly. In our method, a modified non-rectangle gird is employed in backprojection operation to eliminate the space variance of smearing. Then, a sub bandwidth phase gradient autofocus method is designed to implement motion compensation in high resolution case. Finally, real data processing result can validate this autofocus algorithm.