Journal of Astronautics ›› 2013, Vol. 34 ›› Issue (2): 246-253.doi: 10.3873/j.issn.1000-1328.2013.02.014

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Wavefront Curvature Compensation Polar Format Algorithm Based on Digital Spotlighting Preprocessing

MAO Xin hua,  ZHU Dai yin,  ZHU Zhao da   

  1. College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  • Received:2011-10-28 Revised:2012-12-19 Online:2013-02-15 Published:2013-02-25

Abstract:

In this paper, a new wavefront curvature compensation method based on digital spotlighting preprocessing is proposed. First, digital spotlighting preprocessing, filtering and downsampling in 2 dimensional space domain, is performed on echo data. This generates multiple full resolution phase histories of smaller image patches, each corresponding to a narrow beam phase history data where the wavefront curvature effect can be ignored. Due to the inherent non planar motion compensation capability, PFA is used to produce focused fine resolution image for each small patch. Finally, all focused image patches are seamed together to get a full image. Simulation experiments show that the new algorithm has improved focused scene size when applying to phase history generated by non ideal radar flight path.
 

Key words: Synthetic aperture radar, Polar format algorithm, Wavefront curvature compensation, Arbitrary flight path, Digital spotlighting

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