A new cross-range scaling algorithm based on FrFT

Inverse synthetic aperture radar (ISAR) generates two dimensional high resolution images of targets in range-Doppler domain. In order to determine the cross-range dimension of the target or implement polar formatting to reconstruct more focused ISAR images, estimation of the rotation angle is required. A new algorithm for cross-range scaling (CRS) is proposed to estimate the rotation angle, which makes use of the information hidden in the chirp rate of echoes from the scattering centers. A technique based on Fractional Fourier transform (FrFT) is used to estimate the chirp rate, simulation and real data analyses are provided to verify the effectiveness of the proposed algorithm.