High precision imaging algorithm for synthetic aperture radar based on coordinate conversion

New high precision imaging algorithm for low-frequency high squint synthetic aperture radar (SAR) is proposed in this paper for existed SAR algorithms with the problems of defocusing and heavy calculation. The proposed algorithm transforms the SAR data from acquisition Doppler geometry to zero Doppler geometry and then operates ununiform fast Fourier transform (FFT) in range-time domain data to decoupling between range and azimuth. The SAR images focus well after above operations. The computational burden of the proposed algorithm is in the same level as range Doppler(RD) algorithm and has high imaging efficiency. Simulations verify that the proposed algorithm focus well in low frequency high squint SAR. The results demonstrate the correctness of the proposed algorithm.