A Spaceborne SAR Radiometric Calibration Scheme Using Power Transmission Towers

Synthetic aperture radar (SAR) radiometric calibration is essential for quantitative application of SAR images. However, radiometric calibration using typical calibrators, such as transponders and corner reflectors, is quite expensive and requires installation of various ground equipment. To reduce the cost and simplify the calibration process, a spaceborne SAR radiometric calibration method is proposed, using power transmission towers (PTTs) as calibrators. PTTs are widely employed and distributed for electricity power transmission and have persistent scattering characteristics as metallic targets, which makes them ideal radiometric calibrators. For effective spaceborne SAR calibration, the required Radar Cross Section (RCS) information of PTTs can be measured by airborne SAR. Experiments are performed using the Gaofen-3 data for Zhenglanqi, Inner Mongolia. The calibration factor derived by the proposed method is compared with that provided in the original Gaofen-3 product, demonstrating the feasibility of the proposed method.