Circular SAR processing using an improved omega-k type algorithm

Circular SAR processing using an improved omega-k type algorithm

Leilei Kou;Xiaoqing Wang;Jinsong Chong;Maosheng Xiang;Minhui Zhu

【期刊名称】《系统工程与电子技术（英文版）》 【年(卷),期】2010(021)004

【摘要】An improved circular synthetic aperture radar (CSAR) imaging algorithm of omega-k (ω-k) type mainly for reconstructing an image on a cylindrical surface is proposed. In the typical CSAR ω-k algorithm, the rage trajectory is approximated by Taylor series expansion to the quadratic terms, which limits the valid synthetic aperture length and the angular reconstruction range severely. Based on the model of the CSAR echo signal, the proposed al- gorithm directly transforms the signal to the

two-dimensional

(2D)

wavenumber

domain,

not

using

approximation processing to the range trajectory. Based on form of the signal spectrum in the wavenumber domain, the formula for the wavenumber domain in-terpolation of the ω-k algorithm is deduced, and the wavenumber spectrum of the reference point used for bulk compression is ob-tained from numerical method. The improved CSAR ω-k imaging algorithm increases the valid synthetic aperture length and the angular area greatly and hence improves the angular resolution of the cylindrical imaging. Additionally, the proposed algorithm can be repeated on different cylindrical surfaces to achieve three di-mensional