[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-30] Characterizing the Effects of Mid-Latitude MSTIDs on GNSS Positioning Accuracy Across Japan Using a Dense Receiver Network

*RAJESH KUMAR BARAD^1,2、Y. Otsuka²、S. Sripathi^1,3、P. Abadi^2,4、A. Shinbori²、T. Sori²、M. Nishioka⁵、P. Septi⁵ (1.Indian Institute of Geomagnetism, Navi Mumbai, India、2.Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan、3.Equatorial Geophysical Research Laboratory, Tirunelveli, India、4.Research Center for Climate and Atmosphere, Indonesian National Research and Innovation Agency (BRIN), Bandung, Indonesia、5.National Institute of Information and Communications Technology (NICT), Koganei, Tokyo, Japan)

キーワード：MSTIDs, GNSS Positioning, TEC, Positioning Error

The ionosphere significantly impacts the propagation of Global Navigation Satellite System (GNSS) signals and the resulting positioning solution. Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) are wavelike perturbations in electron density that propagate through the mid-latitude ionosphere. These can lead to rapid fluctuations in Total Electron Content (TEC) that degrade GNSS positioning accuracy. This study investigates the spatial and temporal characteristics of mid-latitude MSTIDs using a dense GNSS receiver network spread across the Japanese sector. The Japanese GEONET network's ~1300 GNSS receivers provide an opportunity to analyze the impacts of MSTIDs on GNSS positioning over Japan. The differential TEC and TEC rate derived from GEONET reveal MSTID occurrence and amplitude in the Japanese islands. Carrier phase and pseudorange data from various GEONET stations allow kinematic solutions to be generated before, during, and after MSTID events. The estimation of relative positioning is carried out via double differenced carrier phase and code measurements before, during, and after MSTID events. Statistical analysis examines the perturbations in the kinematic solutions in the north, east, and up directions caused by the MSTIDs. Correlations between the positioning errors and the observed MSTID parameters are evaluated to determine which aspects significantly impact positioning accuracy over Japan. Notably, the findings indicate that GNSS positioning errors range from approximately 10 cm to 1 meter, depending on the amplitude of the MSTIDs. For a specific illustration, a detailed case study is presented, focusing on the MSTID event observed on July 3, 2022, characterized by an amplitude of approximately 1 TEC unit. During this MSTID event, positioning errors of ~25 cm in east-west and north-south directions are identified. The error is notably larger in the up-down direction, reaching up to ~60 cm. These quantitative results significantly contribute to understanding MSTID morphology, dynamics, and their consequential impact on high-precision GNSS positioning in the Japanese region.