Title
High-Resolution Real-Time Imaging Processing for Spaceborne Spotlight SAR With Curved Orbit via Subaperture Coherent Superposition in Image Domain
Abstract
With the increasing of application requirements, the high-resolution real-time imaging processing of the spaceborne spotlight synthetic aperture radar (SAR) has been developed. Since the traditional real-time imaging algorithms have the problems that the range model has errors and the two-dimensional (2-D) space-variance of the equivalent velocity caused by the curved orbit cannot be effectively eliminated. Thus, this article proposes a high-resolution real-time imaging algorithm for spaceborne spotlight SAR with curved orbit via subaperture coherent superposition in image domain. In this article, the echo data are first divided into subapertures to avoid the azimuth spectrum aliasing. After that, the 2-D space-variance of the equivalent velocity caused by the curved orbit can be eliminated by the method of azimuth time scale transformation, higher order phase compensation, and introducing phase transition function. Then, the dechirp function is applied for the subaperture signals to obtain the partial-resolution subaperture images. Finally, these partial-resolution subaperture images are coherently superposed in the image domain to obtain the final full-resolution image of the whole echo data. Moreover, the proposed algorithm improves the real-time performance by adopting the idea that the subaperture data recording and subaperture real-time imaging processing are synchronized, which greatly accelerates the acquisition of the final full-resolution imaging result. At the end of this article, the simulations and the real-time performance analysis are performed to validate the proposed algorithm.
Year
DOI
Venue
2022
10.1109/JSTARS.2022.3150025
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
Keywords
DocType
Volume
Imaging, Real-time systems, Orbits, Synthetic aperture radar, Azimuth, Spaceborne radar, Radar imaging, Curved orbit, high-resolution real-time imaging, spaceborne synthetic aperture radar (SAR), spotlight mode, subaperture coherent superposition
Journal
15
ISSN
Citations 
PageRank 
1939-1404
0
0.34
References 
Authors
0
7
Name
Order
Citations
PageRank
Yanbin Liu100.68
Guang-Cai Sun205.41
Liang Guo315115.26
Mengdao Xing41340162.45
Hanwen Yu503.72
Ruimin Fang600.34
Shiyu Wang711.73