GNSS and SAR Signal Delay in Perturbed Ionospheric D-Region During Solar X-Ray Flares

• Published in: IEEE geoscience and remote sensing letters 2020-07, Vol.17 (7), p.1198-1202
• Main Authors: Nina, Aleksandra, Nico, Giovanni, Odalovic, Oleg, Cadez, Vladimir M., Todorovic Drakul, Miljana, Radovanovic, Milan, Popovic, Luka C.
• Format: Article
• Language: English
• Subjects: Atmospheric modeling; D region; Delays; Electron density; Geodesy; Geodetics; Global navigation satellite system; Global navigation satellite systems (GNSS); Ionosphere; Ionospheric disturbances; Ionospheric models; Ionospheric propagation; Navigation; Navigation satellites; Navigation systems; Navigational satellites; Perturbation methods; Radio waves; SAR (radar); Satellites; Signal delay; Solar x-rays; Synthetic aperture radar; synthetic aperture radar (SAR) interferometry (InSAR); Very Low Frequencies; very-low-frequency (VLF) radio signals; VLF radio waves; X rays
• ISSN: 1545-598X; 1558-0571
• DOI: 10.1109/LGRS.2019.2941643

We investigate the influence of the perturbed (by a solar X-ray flare) ionospheric D-region on the global navigation satellite systems (GNSS) and synthetic aperture radar (SAR) signals. We calculate a signal delay in the D-region based on the low ionospheric monitoring by very-low-frequency (VLF) radio waves. The results show that the ionospheric delay in the perturbed D-region can be important and, therefore, should be taken into account in modeling the ionospheric influence on the GNSS and SAR signal propagation and in calculations relevant for space geodesy. This conclusion is significant because numerous existing models ignore the impact of this ionospheric part on the GNSS and SAR signals due to its small electron density which is true only in quiet conditions and can result in significant errors in space geodesy during intensive ionospheric disturbances.