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.