Geodetic SAR tomography

Abstract

In this paper, we propose a framework referred to as “geodetic SAR Tomography “that fuses the SAR imaging geodesy and TomoSAR approaches to obtain absolute 3D positions of a large amount of natural scatterers. The methodology is applied on four very high resolution (VHR) TerraSAR-X spotlight image stacks acquired over the city of Berlin. Since all the TomoSAR estimates are relative to the same reference point object whose absolute 3D positions are retrieved by means of stereo-SAR, the point clouds reconstructed using data acquired from different viewing angles can be geodetically fused. To assess the accuracy of the position estimates, the resulting absolute shadow-free 3D TomoSAR point clouds are compared to a DSM obtained by airborne LiDAR. It is demonstrated that an absolute positioning accuracy of around 20 centimetre and a meter-order relative positioning accuracy can be achieved by the proposed framework using TerraSAR-X data.