SAR real time motion compensation: Average cancellation method for aircraft motion error extraction

Abstract

Effective motion compensation is the key for achieving high quality SAR images. A recent frequency domain method which is based on an analysis of the azimuth spectrum of SAR raw data to extract aircraft's motion-error, has the advantage of having the ability to operate without accelerometer and INS. However, an antenna with a wide azimuth beam is required. Furthermore, its accuracy depends heavily on the contrast of the ground reflectivity function. A new method based on the time domain approach is presented in this paper. Compared with the existing method, the new approach not only has all the above-mentioned features, but also the added advantages of low computation load requirement as well as the wide-band motion-error extraction capability. Furthermore, it relaxes some requirements on azimuth antenna beamwidth as well as the ground reflectivity function contrast.