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Radar Interferometric Phase Errors Induced by Faraday Rotation

delete2022-01-01
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OA
AI
S
Simon Zwieback *
F
Franz J. Meyer
DOI:10.1109/TGRS.2021.3094996delete
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Abstract

Abstract

En 中文
Ionospheric Faraday rotation distorts satellite radar observations of the Earth's surface. While its impact on radiometric observables is well understood, the errors in repeat-pass interferometric synthetic aperture radar (InSAR) observations and hence in deformation analysis are largely unknown. Because Faraday rotation cannot rigorously be compensated for in nonquad-pol systems, it is imperative to determine the magnitude and nature of the deformation errors. Focusing on distributed targets at L-band, we assess the errors for a range of land covers using airborne observations with simulated Faraday rotation. We find that the deformation error may reach 2 mm in the copol channels over a solar cycle. It can exceed 5 mm for intense solar maxima. The cross-pol channel is more susceptible to severe errors. We identify the leakage of polarimetric phase contributions into the interferometric phase as a dominant error source. The polarimetric scattering characteristics induce a systematic dependence of the Faraday-induced deformation errors on land cover and topography. Also, their temporal characteristics, with pronounced seasonal and quasi-decadal variability, predispose these systematic errors to be misinterpreted as deformation. While the relatively small magnitude of 1-2 mm is of limited concern in many applications, the persistence on semiannual to multiannual time scales compels attention when long-term deformation is to be estimated with millimetric accuracy. Phase errors induced by uncompensated Faraday rotation constitute a nonnegligible source of bias in interferometric deformation measurements.
Keywords:
Faraday effect
Strain
Spaceborne radar
Radar
L-band
Scattering
Covariance matrices
Faraday effect
ionosphere
radar interferometry
synthetic aperture radar

Journal

IEEE Transactions on Geoscience and Remote Sensing cover
IEEE Transactions on Geoscience and Remote Sensing
IF:
8.6
Papers:
2.1W
Citations:
10.7W

Organization

University of Alaska System cover
University of Alaska System
Scholars:
4.6K
Papers: 3.9K
Citations: 27