Radiometric Correction of Dual-Polarization SAR Data Over Steep Terrain

Abstract

Dual-polarization synthetic aperture radar (SAR) data acquired over steep terrain topography is commonly calibrated using the correction methods for single-polarization intensity SAR data. Such kinds of correction methods are generally attained by the illuminated area normalization based on terrain geometry while the case of polarization rotation induced by steep terrain is ignored. To address this issue, this paper proposes a correction method for dual-polarization SAR data over steep terrain, in which both effects of geometry and polarization rotation are taken into account. In this method, correction is achieved based on the original definition of backscattering coefficient by using only intensity SAR values obtained from two channels (co- and cross-polarization) without involving any other amplitude or phase information. The experiments on a set of dual-polarization data correction show that the corrected results generally agree with the facts of relation among SAR data distortion, terrain geometry, and polarization rotation with respect to azimuth and range slope angles of radar, which verifies the effectiveness of the proposed correction method.