Spaceborne SAR Image Geometric Rectification Method without Ground Control Points Using Orbit Parameters Modulation

Abstract

When using the Range-Doppler model for SAR image geometric correction, the error of satellite orbit, imaging parameter and DEM elevation will affect the geometric correction accuracy. A new geometric rectification method has been presented for spaceborne SAR image. First, polynomial was used for parameterizing SAR orbit. Then orbit parameters were corrected by control points that acquired by matching of simulated SAR image and real SAR image. Finally, the precise geometric rectification using corrected parameters was accomplished. The presented method can be applied for SAR image geometric rectification where the ground control points are difficult to be acquired. It has higher precision compared to the geometric rectification based on image simulation and polynomial correction. The Radarsat-2 image was used in experiments, and the ground control points measured by GPS validated the proposed approach