A novel signal-cancellation-based channel phase bias calibration algorithm for spaceborne multi-channel HR WS SAR in azimuth

Combined with digital beam forming (DBF), multichannel synthetic aperture radar (MC-SAR) in azimuth can achieve high-resolution and wide-swath (HRWS) SAR imaging. However, inevitable channel errors lead to a great degradation of DBF performance in practice. To address this problem, a novel channel phase error calibration algorithm is proposed in this letter. Theoretical analysis reveals that the signal of the reference channel can be reconstructed from those of other channels. Although signal cancellation can be roughly realized by using this reference signal and the original signal, there are still residues due to the existence of channel phase errors. Therefore by minimizing the difference between these two signals, the channel phase errors can be precisely derived. The effectiveness of the proposed algorithm is validated by experimental results.