Physic and Experimental Issues on High Resolution SAR Imaging of Urban Area

Here are presented issues about building or urban area high resolution imaging using synthetic aperture radar (SAR). Promises of circular imaging are assessed. Indeed, this acquisition mode, though available only to airborne sensors, has the potential to solve shadow and overlay problem through rotation of the slantrange projecting direction. It has also an intrinsic elevation dependency that would allow "along track stereo" reconstruction. This is illustrated from several recent circular/spotlight acquisitions over urban areas.