Robust phase mismatch calibration for multichannel sliding spotlight SAR imaging

摘要

This paper investigates the aspect of phase mismatch calibration for multichannel in azimuth synthetic aperture radar (SAR) operating in the sliding spotlight mode. In conventional multichannel stripmap SAR systems, it is assumed that all the sub-aperture antenna phase centers are along the sensor track during system operation. However, in the multichannel sliding spotlight mode, the utilization of beam progressive sweeping in azimuth causes movement of the antenna electromagnetic phase centers along with the time-variant beam squinted angle, which brings space-varying phase error between different channels. In this paper, a calibration method based on the imaging geometry was developed to address this problem, which needs no iteration or block-wise processing. Processing with experimental data obtained from a C-band dual-channel sliding spotlight airborne SAR shows effective channel phase mismatch cancellation.