Range focusing for large scene circular SAR

A recent circular synthetic aperture radar data collection contained various vehicles and calibration targets placed throughout a 5 km scene. By observing multiple orbits of the radar, the down-range distance measurements to scattering features show noticeable drift on the order of 2 m from orbit to orbit. The large scene contained 14 quad-trihedral (QT) calibration targets with radar cross sections that are similar to point targets in the elevation range of the scene. This paper presents an algorithm that uses the QTs to generate global range focusing parameters. Qualitative and quantitative results show the focusing provides a significant improvement to vehicle target discrimination.