A Modified Space-Variant Phase Filtering Algorithm of PFA for Bistatic SAR

Wavefront curvature effects grow worse in spotlight Bistatic synthetic aperture radar (BSAR) imagery when reconstructed via polar format algorithm (PFA) under the large-scale scene. The wavefront curvature error, which causes geometric distortion and defocuses to the image, is induced by the faulty...

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Bibliographic Details
Published in:IEEE geoscience and remote sensing letters 2022, Vol.19, p.1-5
Main Authors: Han, Shengliang, Zhu, Daiyin, Mao, Xinhua
Format: Article
Language:English
Subjects:
Algorithms
Azimuth
Bistatic synthetic aperture radar (BSAR)
Computer applications
Curvature
Distortion
Error analysis
Error compensation
Error correction
Filtration
Geometry
Image reconstruction
Imagery
Imaging
Mathematical models
Numerical simulations
Phase distortion
Phase error
polar format algorithm (PFA)
Radar imaging
Receivers
SAR (radar)
space-variant post-filtering (SVPF)
Synthetic aperture radar
Wave fronts
wavefront curvature
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Summary:Wavefront curvature effects grow worse in spotlight Bistatic synthetic aperture radar (BSAR) imagery when reconstructed via polar format algorithm (PFA) under the large-scale scene. The wavefront curvature error, which causes geometric distortion and defocuses to the image, is induced by the faulty hypothesis of the planar wavefront. Due to the approximated or unsegmented wavefront curvature error, conventional compensation algorithms experience different degrees of performance restriction. In this letter, the geometric distortion error and the intact defocus error are separated and analyzed for the first time. Based on the separated phase error model, a modified space-variant post-filtering (MSVPF) algorithm is proposed to correct the wavefront curvature effects of the PFA image. Two major contributions of this algorithm are as follows. First, as no high-order term is ignored in the constructed space-variant filter, the proposed algorithm can compensate for the defocus error with any order. Second, MSVPF employs a separate strategy to correct the space-variant defocus and geometric distortion, which avoids high overlap rate in subimage processing and maintains the computational efficiency of the original SVPF. The effectiveness of the proposed algorithm is demonstrated by numerical simulations.
ISSN:1545-598X
1558-0571
DOI:10.1109/LGRS.2020.3047617