Calibration of High-Resolution Polarimetric Imaging SAR Accounting For the Impulse Response of the Active Point-Target and The SAR Ambiguity Function

In this paper, calibration of a high-resolution imaging SAR using an active point target is considered. Most of the time, the exact position of the calibration target with respect to the ground pixel cannot be determined ahead of time. As we show in this paper, an offset in the location of the calibration target with respect to the center of the ground pixel can result in a rather large calibration error if not properly accounted for. Furthermore, depending on the pixel size, the impulse response of the active calibration target may span over a long enough time to create aliasing effects over a few adjacent pixels. This paper will investigate both of these effects and introduce a method to accurately calibrate the SAR in the presence of these effects. It is shown that the proposed method also reduces the effect of clutter on the accuracy of calibration.