Amplitude-phase calibration method for downward-looking SAR

Airborne downward-looking linear-array three dimensional synthetic aperture radar (LA-3D-SAR) can achieve high-resolution three dimensional imagery with a uniform antenna array. However, the actual 3D imagery is unavoidably degraded by amplitude-phase errors due to non-ideal antenna characteristics and motion measurement deviations. This paper investigates the effects of these errors on the forms and the degrees of image quality degradation, and considers the use of corresponding calibration methods to eliminate the effects of errors. Two calibration methods are proposed, which are based on external parallel and point target calibrators, respectively. At last, real data experiments have shown the validity of the analyses as well as the effectiveness of the proposed calibration methods.