Analysis of SAR radiometric calibration accuracy with practical point targets

The calibration factors and image quality parameters for SAR data are usually derived from the impulse response function (IRF) of a point target such as corner reflectors (CR) or active transponders on the ground test site. The peak estimation method and the integral method are efficient technique to calculate radiometric calibration accuracy. Since the peak estimation method requires knowledge of the equivalent rectangle system resolution which is sensitive to image focusing, the integral method is usually recommended. However the integral method is sometimes inaccurate, due to the sidelobes of strong speckle and background contribution around the point target. For the practical case of SAR image, the integrated energy is estimated by simple summation of the mainlobe area of a point target. In this paper, radiometric calibration accuracy are evaluated the point target of a simulated X-band SAR image and practical case of targets.