一种超高分辨率机载聚束SAR两维自聚焦算法

ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2012, Vol. 33 ›› Issue (7): 1289-1295.

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2-D Autofocus Algorithm for Ultra-high Resolution Airborne Spotlight SAR Imaging

MAO Xinhua, ZHU Daiyin, ZHU Zhaoda

College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

Received:2011-09-01 Revised:2012-02-16 Online:2012-07-25 Published:2012-07-24
Supported by:
Defense Industrial Technology Development Program (B2520110008); National Natural Science Foundation of China (61071165); Aeronautical Science Foundation of China (20102052024); Special Fund of China Postdoctoral Science Foundation (201003586); New Century Program for Excellent Talents of Ministry of Education of China (NCET-09-0069); Fundamental Research Funds for the Central Universities (NS2012097)

Abstract

Abstract: Synthetic aperture radar (SAR) images are often blurred by phase perturbations induced by uncompensated sensor motion and /or unknown propagation effects caused by turbulent media. To get refocused images, autofocus proves to be useful post-processing technique applied to estimate and compensate the unknown phase errors. However, an important drawback of the conventional autofocus algorithms is that they are able to compensate for only one-dimensional azimuth phase errors. As the resolution increase, residual range cell migration, which makes the defocus inherently two-dimensional(2-D), becomes a new challenge. In this paper, the analytical relationship between the residual range cell migration and azimuth phase error in polar format imagery is developed. Utilizing this relationship, a 2-D autofocus algorithm that can simultaneously compensate for the residual range migration and azimuth phase error is proposed. The results of real data processing validate the effectiveness of the proposed method.

Key words: synthetic aperture radar, ultra-high resolution imaging, autofocus, residual range migration, azimuth phase error

CLC Number:

V243.2
TN958

MAO Xinhua, ZHU Daiyin, ZHU Zhaoda. 2-D Autofocus Algorithm for Ultra-high Resolution Airborne Spotlight SAR Imaging[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2012, 33(7): 1289-1295.

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2-D Autofocus Algorithm for Ultra-high Resolution Airborne Spotlight SAR Imaging

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