Far-field radar cross section determination using near-field ISAR imaging techniques

Inverse synthetic aperture radar (ISAR) imaging is a powerful tool for the characterization of radar targets. Since the direct determination of the far-field radar cross section (RCS) typically requires expensive arrangements and equipment, short distance ISAR imaging of the radar targets has been proposed as alternative method, where the resulting near-field images can be used to extract the far-field radar cross section of the target. This contribution compares the performance of different near-field imaging techniques together with a new approach and accuracy improvements. Furthermore, a detailed insight in the imaging process is given, leading to reliable sampling rules, thus together with calibration and focusing techniques a complete concept for accurate far-field RCS extraction is given.