Ortho-rectification of polarimetric Radarsat-2/RCM data with accurate lidar DSM

Abstract

Ortho-rectification using digital terrain models is a key issue for full polarimetric complex synthetic aperture radar (SAR) data because resampling the complex data can corrupt the polarimetric phase, mainly in study sites with relief. This research thus compared two approaches for the ortho-rectification of the complex SAR data: the polarimetric processing is performed before (scientist approach) or after (user approach) the geometric processing. A quantitative evaluation between the two approaches as a function of different geometric and radiometric parameters was thus performed to quantify the impact of the ortho-rectification on the complex polarimetric SAR. Radarsat-2 fine-quad data acquired over a rolling relief study site were geometrically processed using a lidar digital surface model. The evaluation results showed than the terrain slopes and land covers can potentially corrupt the polarimetric complex SAR data during the ortho-rectification. Advices are finally provided to reduce these impacts to an acceptable level for the users and their applications. Preliminaries results of simulated compact polarimetric SAR data of the new Canadian Radar Constellation Mission will be presented at the Conference.