Estimation of Doppler parameters for spaceborne SAR based on fractional Fourier transform

In spaceborne synthetic aperture radar system, the accuracy of the Doppler centroid and Doppler rate affects the imaging quality directly. Different from the traditional estimating method, a method for Doppler parameters´ estimation based on fractional Fourier transform is presented in this paper. This method estimates the Doppler centroid and Doppler rate in the same process that has less computing complexity. The results of estimating the Doppler parameters of the simulated and real data of Radarsat-1 proves that this method can give an accurate estimation.