In synthetic-aperture radar (SAR), the radar signal, recorded as an interferogram, exhibits a defect known as range curvature. The two dimensions of the interferogram are coupled and cannot be processed separately, leading to image degradation. Two variations of a method of correcting for range curvature are presented. They both involve the insertion of a cylindrical lens or lenses near the region of the Fourier-transform plane of a standard tilted-plane SAR processor. Variable tilt of the lens(es) controls the amount of correction. In the presence of pointing errors of the SAR antenna, an extra cross-coupling factor is introduced. It is corrected by a simple rotation of the range-curvature corrector.
E. Barry Felstead,
"Optical Range-Curvature Correction For Synthetic-Aperture Radar (SAR) Signals", Proc. SPIE 0231, 1980 Intl Optical Computing Conf I, (22 August 1980); doi: 10.1117/12.958861; https://doi.org/10.1117/12.958861