Autofocused spotlight SAR image reconstruction of off-grid sparse scenes
Date
2017Source Title
IEEE Transactions on Aerospace and Electronic Systems
Print ISSN
0018-9251
Publisher
Institute of Electrical and Electronics Engineers Inc.
Volume
53
Issue
4
Pages
1880 - 1892
Language
English
Type
ArticleItem Usage Stats
208
views
views
254
downloads
downloads
Abstract
Synthetic aperture radar (SAR) has significant role in remote sensing. Phase errors due to uncompensated platform motion, measurement model mismatch, and measurement noise can cause degradations in SAR image reconstruction. For efficient processing of the measurements, image plane is discretized and autofocusing algorithms on this discrete grid are employed. However, in addition to the platform motion errors, the reflectors, which are not exactly on the reconstruction grid, also degrade the image quality. This is called the off-grid target problem. In this paper, a sparsity-based technique is developed for autofocused spotlight SAR image reconstruction that can correct phase errors due to uncompensated platform motion and provide robust images in the presence of off-grid targets. The proposed orthogonal matching pursuit-based reconstruction technique uses gradient descent parameter updates with built in autofocus. The technique can reconstruct high-quality images by using sub Nyquist rate of sampling on the reflected signals at the receiver. The results obtained using both simulated and real SAR system data show that the proposed technique provides higher quality reconstructions over alternative techniques in terms of commonly used performance metrics.
Keywords
AutofocusCompressive sensing (CS)
Off-grid
Radar
Sparse
Spotlight synthetic aperture radar (SAR)
Communication channels (information theory)
Errors
Image processing
Image reconstruction
Phase noise
Remote sensing
Synthetic aperture radar
High quality images
Orthogonal matching pursuit
Performance metrics
Reconstruction techniques