Two-dimensional non-uniform FFT for image formation of high-squint SAR

The high-resolution imaging for high-squint synthetic aperture radar (SAR) is still a difficult issue due to large range migration and strong range dependence. An extended keystone transform (EKT) is introduced to correct more complex range cell migration and range-variant, then a two-dimensional non-uniform fast Fourier transform (2D NUFFT) is proposed to obtain the focused image. Simulation results are given to validate the effectiveness of the method.