SAR Image Absolute Radiometric Calibration Based on RCS Modeling of Communication Tower

  Objectives  Aiming at the problems of the limited setting of corner reflectors in synthetic aperture radar (SAR) image radiation calibration, a method of using communication towers to assist in measuring the absolute radiation calibration constants of SAR images is proposed.

  Methods  Firstly, an equivalent simplified model is established for the upper and lower parts according to the unique geometric structure characteristics of the signal tower which are the equivalent dihedral angle and the cylinder scatterer, respectively. Secondly, on this basis, we use the physical optics method to calculate the radar cross section (RCS) of each part and superimpose the overall RCS of the communication tower model. Finally, according to the overall RCS, the pulse response energy and the absolute radiometric calibration constant of the communication tower in SAR image are solved using the integral method.

  Results  Experimental results of the simplified model are compared with the simulation results of FEKO in order to prove the accuracy of the proposed method. It saves the time required for simulation and therefore greatly improves computational efficiency.

  Conclusions  The absolute radiation calibration constants of real SAR images are calculated and compared with the nominal parameters, the proposed method is feasible and effective.