Performance analysis and improvement of phase gradient autofocus algorithm
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摘要: 描述了相位梯度自聚焦(PGA)算法的实现步骤.基于对PGA算法的性能分析及对PGA算法的基本步骤所起作用的研究,提出了两种改进的方法.首先,通过对加窗方法的改进,提高了算法的聚焦速度;另外,通过选择适当的距离行进行处理,使算法即使在低信噪比的条件下也能达到较好的聚焦效果.Abstract: The realization of phase gradient autofocus (PGA) algorithm was described. Based on the analysis of the shortcoming of PGA and the study of the roles of the basic steps of phase gradient autofocus algorithm, two methods were proposed to improve the performance of the PGA algorithm. First, a new way to select window width was developed, which can accelerate the convergence of the autofocus; second, by selecting the appropriate row to processing, the effect of convergence of focus is good even under the condition of low SNR(signal-to-noise rate).
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Key words:
- synthetic aperture radar /
- phase errors /
- phase gradient autofocus
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[1] Jakoatz C V, Wahl D E. Spotlight-mode synthetic aperture radar:a signal processing approach[M]. Boston:Kluwer Academic Publishers, 1996.221~222 [2]Wahl D E,Eichel P H,Ghiglia D C, et al. Phase gradient autofocus——a robust tool for high resolution SAR phase correcton[J]. IEEE Transactions on Aerospace and Electronic Systems, 1994,30(3):827~834 [3]Jakowatz C V,Wahl D E. Eigenvector method for maximum- likelihood estimation of phase errors in synthetic-aperture radar imagery [J]. Optical Society of America,1993,10(12):2539~2545 [4]Tsakalides P,Nikias C L. High-resolution autofocus techniques for SAR imaging based on fractional lower-order statistics[J]. IEEE Proceedings-Radar,Sonar and Navigation,2001,148(5):267~276
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