Slice convolution based slope estimation for SAR doppler ambiguity resolver

In high-quality Synthetic Aperture Radar (SAR) processing, the estimation of the Doppler centroid ambiguity from the received data is an essential procedure because it is related to the signal to noise ratio, geometric distortion, and radiometric error of the final SAR image. Conventional algorithms based on Radon transform can solve the ambiguity accurately but still have a certain degree of high computational load. In this paper the feature of the SAR range cell migration (RCM) in the range-Doppler (RD) domain is analyzed. Taking into account the fact that the absolute Doppler centroid and RCM skew slope in RD domain are directly correlated to each other, a new simple method is developed which is directly operated in the RD domain rather than taking the Radon transform of the range-compression image. Compared to the traditional Radon transform algorithms, this new method can greatly reduce the computation complexity while keep the higher absolute Doppler centroid accuracy. Experiments with real space-borne SAR data are applied to validate the effectiveness of this algorithm.