A fast and accurate algorithm for SAR Doppler center frequency estimation

A fast and accurate algorithm to estimate Doppler Center Frequency (DCF) automatically from spaceborne Synthetic Aperture Radar (SAR) raw data is presented. Firstly, the principle of DCF estimation is examined and it is pointed out that the speckle nature of the SAR image plays an essential role. Secondly, the origin of estimation error by the conventional method which utilizes azimuth power spectra of raw SAR data is analyzed on the basis of the principle stated above. Thirdly, a new algorithm which is fast and accurate is derived from the estimation error analysis. Lastly, the comparison between conventional methods and the proposed algorithm is made using SEASAT-I SAR data, and the effectiveness of the algorithm is confirmed.