Ionospheric Scintillation Impacts on L-band Geosynchronous D-InSAR System: Models and Analysis

The upcoming L-band geosynchronous differential interferometric synthetic aperture radar (GEO D-InSAR) system has the capability to monitor rapid deformations due to its excellent revisit capability. However, because of its low working frequency, the random ionospheric scintillation signal will degrade the deformation retrieval accuracy by giving rise to extra interferometric phase errors and obvious decorrelations in GEO D-InSAR interferograms. In this paper, aiming at impacts of ionospheric scintillations on GEO D-InSAR system, we theoretically establish its interferometric phase error and decorrelation models by using the scintillation statistical parameters directly. Simulations based on the scintillation sampling model, the Cornell university scintillation model, the phase screen mode, and the ionospheric scintillation signal acquired by the ground-based global positioning system receiver are carried out to verify the proposed model. Moreover, quantitative analyses of the ionospheric scintillation interferometric phase error and decorrelation impacts under different scintillation cases are obtained. The results verify that the proposed models and the analyses are effective. Meanwhile, they also suggest that the generated defocusing decorrelation dominates the ionospheric scintillation impacts on GEO D-InSAR, which can induce a coherence loss of more than 0.1 in the interferogram when only one image of the interferometric pair suffers the weak ionospheric scintillation.