Abstract: Platform of airborne Synthetic Aperture Radar (SAR) is easily influenced by environmental factors in flight, which would introduce phase error and lead to image blurring. As an image autofocus algorithm, even though PACE algorithm have advantages on high robustness and can estimate high-frequency phase error, it’s limited in high real-time demanded situation by its computation complexity. So we proposed a new optimized PACE algorithm which combined the primary PACE algorithm with a sub-aperture polynomial fitting PACE algorithm to optimize the processing efficiency in this article and make a detailed explanation of the principle and realization of this optimized PACE algorithm. Our experiment on real data proved that the new optimized PACE algorithm can achieve the same compensated image accuracy in less processing time compared with the primary PACE algorithm.

Key words: motion compensation, PACE algorithm, phase error estimation and compensation