A novel SAR imaging algorithm based on FrFT and CS

Synthetic aperture radar (SAR) radiates the chirps in the range direction, and their echoes also have the features of the chirp in the azimuth direction, so a novel imaging algorithm based on the fractional Fourier transform (FrFT) and the chirp scaling (CS) operation was proposed. The algorithm applied the CS operation to eliminate the space-variant of the range cell migration, and utilized the frequency-shift and compression properties of the FrFT to perform the bulk range cell migration correction and the range compression. After the FrFT on the azimuth direction, the target image in two-dimensional fractional Fourier domain was obtained. This algorithm may focus the target image described by two-dimensional impulse function only through one FFT and two FrFTs, hence its computational efficiency is improved significantly, which is superior to that of the classical CS algorithm and FrCSA.