A Novel Technique for Inversion of Rotation Angles in Built-Up Areas

In previous publications, it is generally believed that the rotated buildings in built-up areas can induce polarization orientation angles, which cause overestimation of the volume scattering contribution. However, we found that the rotation effect of the double-bounce scattering wall-ground structures cannot be accurately expressed by an orientation angle. In this letter, dihedrals are used to simulate the wall-ground structures, and a novel technique for inversion of rotation angles in built-up areas is proposed. This letter is committed to directly inverting rotation angles rather than orientation angles. Then the rotation angles are compensated into the measured scattering matrix instead of deorienting the coherence matrix. C-band GF-3 and L-band ALOS-2 polarimetric data of San Francisco are used to verify the effectiveness of the proposed inversion technique.