Ionospheric gradients in multi-constellation global navigation satellite system signals onboard UAV using GIM and Klobuchar model over Thailand region

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dc.contributor.authorAnsari, Kutubuddin
dc.contributor.authorPanda, Sampad Kumar
dc.contributor.authorVenkatesh, Kavutarapu
dc.contributor.authorJamjareegulgarn, Punyawi
dc.date.accessioned2026-08-06T10:56:07Z
dc.date.available2026-08-06T10:56:07Z
dc.date.issued2026-07-01
dc.description.abstractThe effects of the ionosphere on Global Navigation Satellite System (GNSS) signals have been a focal point of research nowadays. During adverse ionospheric conditions, ionospheric gradients become more pronounced and disruptive compared to quiet days, potentially leading to increased positioning errors or loss of satellite signal lock. We introduce an ionospheric spatial gradient estimation method to detect the anomalous gradients from multi-constellation GNSS signals (i.e., GPS, GLONASS, and Galileo) signals recorded by the onboard sensor of flying real-time kinematic unmanned aerial vehicle (RTK UAV) over the Thailand region. We employ the Klobuchar model and global ionospheric maps (GIMs) for estimating the slant total electron contents (STECs) and the corresponding ionospheric spatial gradients between base station and rover (RTK UAV) receivers among the studied multi-constellation systems. The results show that the STEC values estimated from IGS-GIM are larger than those computed by Klobuchar model. Such kind of gradient variation cannot show a perfect correlation due to limited accuracy of Klobuchar model parameters. As for our analysis, the ionospheric spatial gradients estimated from GPS satellites are higher than those calculated from GLONASS and Galileo satellites due to the smallest differences between the two successive positions of flying rover estimated from GPS satellites. The outcomes from this study complement the multi-GNSS cooperative strategy for monitoring ionospheric gradients, thereby mitigating the adverse effects in dynamic positioning and navigation solutions over low-latitude regions.
dc.identifier.citationAdvances in Space Research, 78(1), 331-343, 2026
dc.identifier.doi10.1016/j.asr.2025.07.092
dc.identifier.issn02731177
dc.identifier.other2-s2.0-105012727192
dc.identifier.urihttps://dspace.kmitl.ac.th/handle/123456789/18262
dc.sourceAdvances in Space Research
dc.subjectGlobal ionosphere maps
dc.subjectGlobal Navigation Satellite System
dc.subjectKlobuchar model
dc.subjectReal-time kinematic positioning
dc.subjectSpatial gradient model
dc.subjectUnmanned aerial vehicle
dc.titleIonospheric gradients in multi-constellation global navigation satellite system signals onboard UAV using GIM and Klobuchar model over Thailand region
dc.typeArticle

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