A Novel Spectrum Reconstruction and Imaging Processing Method for Squint Multichannel SAR

Azimuth multichannel synthetic aperture radar(SAR) is a form of SAR with one transmitter and several receivers, which is able to obtain both high resolution and wide swath imaging. Azimuth spectrum reconstruction is core operation in the data processing of azimuth multichannel SAR. The spatial variation of Doppler center frequency is non-ignorable in multichannel SAR of squint view, meanwhile, in sliding spotlight SAR imaging mode, the Doppler spectrum of the signal increases greatly due to the rotation of the beam direction, thus, the traditional reconstruction algorithm fails to reconstruct the signal spectrum correctly. To solve above problems, an improved azimuth spectrum reconstruction and imaging processing algorithm for squint multichannel SAR in sliding spotlight mode is proposed. By analyzing the characteristics of multichannel signals in two-dimensional frequency domain, a new spectrum reconstruction matrix is established. Besides, by combining the Deramp operation with the reconstruction algorithm, the Doppler bandwidth caused by the rotation of the beam center is removed. Finally, imaging algorithm of single channel SAR is used to image the reconstructed signal. Simulation experiments verify the effectiveness of the method.