An Efficient Snapshot-by-Snapshot Imaging Scheme for Multichannel Forward-Looking SAR

By simultaneously exploiting platform motion information and the phase differences among different channels, multichannel synthetic aperture radar (SAR) can realize forward-looking imaging. However, existing imaging schemes usually require the completion of synthetic apertures for imaging processing and face typical problems of high computational complexity and large storage requirements. To address these challenges, an efficient snapshot-by-snapshot imaging scheme is designed and implemented in this article. In this scheme, fast Fourier transform (FFT) is adopted to realize fast focusing of each snapshot first. Then, range registration of different snapshots is achieved by constructing matched filters considering the range differences, and the space-variant Doppler phase is compensated snapshot-by-snapshot to enable coherent summation of the results of each snapshot. Meanwhile, by using the information provided by the inertial navigation device, the motion error compensation of the platform is embedded into the imaging process. At last, the simulated and measured data experiments are illustrated to verify the effectiveness of the proposed scheme in terms of computational efficiency and imaging performance.