Aspects of 3D tomography for multiple-pass spotlight-mode airborne SAR

Three-dimensional SAR tomography makes use of radar data acquired at different depression angles to synthesise an aperture in elevation and thereby undo layover and resolve along height. Focusing on one tomographic method appropriate to a spotlight-mode airborne collection system, the details of spatial bandwidth usage and point-spread function are described, and the phase modulation effects of the initial two-dimensional image formation stage are analysed in terms of the impact on the tomographic processing. Finally, an adaptive beamforming approach is investigated for the improvement of height resolution.