Title :
Extension and Evaluation of PGA in ScanSAR Mode using Full-Aperture Approach
Author :
Ning Li ; Wang, Ruiqi ; Yunkai Deng ; Jiaqi Chen ; Zhimin Zhang ; Yabo Liu ; Fengjun Zhao ; Xiaodong Gong ; Zhihuo Xu
Author_Institution :
Dept. of Space Microwave Remote Sensing Syst., Inst. of Electron., Beijing, China
Abstract :
In order to enable a testbed for spaceborne scanning synthetic aperture radar (ScanSAR) mode, in this letter, a ScanSAR autofocusing approach for airborne platforms has been developed. Autofocusing algorithms, such as the phase gradient autofocus (PGA) algorithm, prove to be a useful postprocessing technique to get refocused synthetic aperture radar images. However, conventional stripmap PGA does not work in ScanSAR mode when the full-aperture approach is used, due to the periodic data gaps in each subswath. To solve this problem, we extend the stripmap PGA to ScanSAR with some modifications, mainly in the subaperture segmentation and phase error estimation steps. The performance of extended stripmap PGA is evaluated by an airborne ScanSAR data set containing different types of terrain, with a high spatial resolution up to 3.5 m in azimuth.
Keywords :
airborne radar; gradient methods; image resolution; phase estimation; radar imaging; synthetic aperture radar; SAR image autofocusing; ScanSAR autofocusing approach; ScanSAR mode; airborne ScanSAR; full aperture approach; periodic data gaps; phase gradient autofocus; postprocessing technique; spaceborne scanning synthetic aperture radar; spatial resolution; stripmap PGA; subaperture phase error estimation; Azimuth; Electronics packaging; Estimation; Radar imaging; Spaceborne radar; Synthetic aperture radar; Full-aperture; phase gradient autofocus (PGA); scanning synthetic aperture radar (ScanSAR); subaperture phase errors (SPEs);
Journal_Title :
Geoscience and Remote Sensing Letters, IEEE
DOI :
10.1109/LGRS.2014.2365521
