Phase Mismatch Calibration of the Multichannel SAR Based on Azimuth Cross Correlation

Multiple-azimuth-channel (MAC) synthetic aperture radar (SAR) systems can overcome the minimum-antenna-area constraint. However, channel phase imbalance and range sampling time error can degrade the quality of the final image. To deal with these two problems, a calibration method based on the azimuth cross correlation is presented in this letter. The proposed method applies the azimuth cross-correlation operation after transforming the received signals of each channel into range frequency domain, where the phase of the cross-correlation function is linear with the range frequency. We obtain the range sampling time error by testing this line´s slope, and then the phase mismatch can be derived. Simulation experiments and real data processing results validate the proposed method.