ACTA AERONAUTICAET ASTRONAUTICA SINICA >
Autofocus Method of Airborne SAR Imagery Reconstructed via Backprojection
Received date: 2013-12-24
Revised date: 2014-07-27
Online published: 2014-08-15
Supported by
China Postdoctoral Science Foundation (2014M551630); Jiangsu Planned Projects for Postdoctoral Research Funds (1302089B); Natural Science Foundation of the Jiangsu Higher Education Institutions of China(14KJB510024); Fundamental Research Funds for the Central Universities (NJ20140008); NUAA Fundamental Research Funds(NS2013023); Open Reasearch Program of State Key Laboratory of Millimeter Waves (K201506)
Backprojection algorithm (BPA) is a classic time domain synthetic aperture radar(SAR) imaging method. Since the imagery reconstructed via BPA is derived via interpolation and accumulation of SAR phase history data, defocus due to motion error will along variant directions and hence traditional autofocus methods cannot be applied directly. To solve this problem, a novel autofocus method for BPA reconstructed imagery is proposed in this paper. Based on the analysis of motion phase error and range migration of BPA processed data, imaging grid is modified to eliminate the space variance of defocus in imagery. The reconstructed SAR imageries after modification can be motion compensated by the phase gradient autofocus (PGA) algorithm in low and moderate resolution cases. Point target simulation results and real data results validate this algorithm.
WANG Xin , ZHU Daiyin , JIANG Rui . Autofocus Method of Airborne SAR Imagery Reconstructed via Backprojection[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2014 , 35(11) : 3074 -3081 . DOI: 10.7527/S1000-6893.2014.0168
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