Range cell migration correction for bistatic SAR image formation

Range cell migration correction (RCMC) is the key process in the imaging formation of the bistatic SAR. Due to the existence of double-square-root in the bistatic range equation, the RCMC in the general bistatic SAR configuration is more complicated than the traditional monostatic method. In this letter, the range cell migration of bistatic SAR system is analysed in detail, and a novel data transformation is derived. From the derivation, we find that the original keystone transform is only a special case of our proposed transformation, so that we called it the generalized keystone transform. Compared with the original keystone transform, this generalized method can correct more complex range cell migration nicely. After the generalized keystone transform processing, the range cell migration is eliminated closely, and the focused image with full range and Doppler resolution can be obtained using the fast Fourier transform. Finally, a hybrid spaceborne/airborne bistatic SAR numerical simulation is performed to validate the proposed processing procedure.