Calibrator Irregularity Error Compensation for Radar Cross Section Measurement

Calibration isan important step in measuring the electromagnetic scattering from a target. Metal spheres are usually selected as calibrators in the calibration process. However, real spherical calibrators are not perfect spheres, which cause calibration errors due to their geometric irregularity and thus affect the radar cross section (RCS) prediction accuracy for the target. A method of estimation and compensation based on high-resolution range profiles (HRRPs) of calibrators is proposed. First, the scattering of a real-world spherical calibrator is measured using the sweep-angle and the sweep-frequency strategies. Then, the error curves are obtained by comparing the HRRPs of the real-world calibrator and its theoretical solutions at each incident angle, which are also used to compensate the RCS error of the real-world spherical calibrator. Finally, the corrected RCS of the calibrator is adopted to access the accurate RCS of the target being tested. The results of simulation and testing show that the proposed method reduces the root mean square error of the RCS of the target by 40%, which demonstrates the effectiveness of the presentedmethod.