title: A Synthetic Bandwidth Method for High-Resolution SAR Based on PGA in the Range Dimension.
abstract: The synthetic bandwidth technique is an effective method to achieve ultra-high range resolution in an SAR system. There are mainly two challenges in its implementation. The first one is the estimation and compensation of system errors, such as the timing deviation and the amplitude-phase error. Due to precision limitation of the radar instrument, construction of the sub-band signals becomes much more complicated with these errors. The second challenge lies in the combination method, that is how to fit the sub-band signals together into a much wider bandwidth. In this paper, a novel synthetic bandwidth approach is presented. It considers two main errors of the multi-sub-band SAR system and compensates them by a two-order PGA (phase gradient auto-focus)-based method, named TRPGA. Furthermore, an improved cut-paste method is proposed to combine the signals in the frequency domain. It exploits the redundancy of errors and requires only a limited amount of data in the azimuth direction for error estimation. Moreover, the up-sampling operation can be avoided in the combination process. Imaging results based on both simulated and real data are presented to validate the proposed approach.
authors.affiliation: School of Electronic and Information Engineering, Beihang University, Beijing 100191, China. lijincheng_buaa@163.com.
authors.forename: Jincheng
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Electronic and Information Engineering, Beihang University, Beijing 100191, China. chenjie@buaa.edu.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Electronic and Electronic Engineering Department, University of Sheffield, Sheffield S1-3JD, UK. w.liu@sheffield.ac.uk.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: School of Electronic and Information Engineering, Beihang University, Beijing 100191, China. wangpb7966@buaa.edu.cn.
authors.forename: Pengbo
authors.initials: P
authors.lastname: Wang
authors.affiliation: School of Electronic and Information Engineering, Beihang University, Beijing 100191, China. lics@buaa.edu.cn.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Li
keywords: synthetic aperture radar (SAR); synthetic bandwidth; ultra-high range resolution