Rigorously geometric correction for air-borne SAR images based on affine transformation

Under the condition that the accuracy of the air-borne platform is unknown, an affine transformation model made up of unknown parameters such as rotation, scale and translation is proposed for Synthetic Aperture Radar (SAR) image geometric correction. These parameters in this model have real physical meanings compared to that in the traditional polynomial models. Based on the characteristics of geometric distortions in SAR images, four unknown parameters, i.e., one rotation angle, two scale and two translation parameters, are selected for geometric correction. Different imaging look directions modes including left and right are all considered in this transformation. One real air-borne SAR image with 0.2m resolution was used to validate the availability of this method. In addition, Ground Control Points (GCP) were surveyed by the technique of Real Time Kinematic (RTK) to resolve the unknown parameters and evaluate the image geometric correction results.