The Mechanism for GNSS‐Based Kinematic Positioning Degradation at High‐Latitudes Under the March 2015 Great Storm

Abstract

In this study, we focus on the kinematic precise point positioning (PPP) solutions at high‐latitudes during the March 2015 great geomagnetic storm. We aim to discover the mechanism behind the positioning degradation from the perspective of the impacts of the storm‐induced ionospheric disturbance on the global navigation satellite system (GNSS) data processing. We observed that the phase scintillation dominated the amplitude scintillation at high‐latitudes and the variation pattern of the rate of total electron content index (ROTI) was consistent with that of the phase scintillation during the storm. The kinematic PPP errors at high‐latitudes were almost three times larger than those at the middle‐ and low‐latitude, which were accompanied by large ROTI variations. From the perspective of GNSS data processing, the large positioning errors were also found to be related to the large number of satellites experiencing cycle slips (CSs). Based on the lock time from the ionospheric scintillation monitoring receiver, we found that a large amount of the CSs was falsely detected under the conventional threshold of the CS detector. By increasing such threshold, the kinematic positioning accuracy at high‐latitudes can be improved to obtain similar magnitude as at middle‐ and low‐latitude. The improved positioning accuracy may suggest that the ionospheric disturbance induced by the geomagnetic storm at high‐latitudes has minor effects on triggering the CSs. Therefore, precise positioning can be achieved at high‐latitudes under geomagnetic storms, given that the CS problem is well addressed.

Dependencies of GPS Scintillation Indices on the Ionospheric Plasma Drift and Rate of Change of TEC Around the Dawn Sector of the Polar Ionosphere

“…Recently, several researchers have been using proxy scintillation indices developed from the estimated TEC of GNSS observables, the primary one being the rate of TEC (ROT) and rate of TEC index (ROTI) (e.g., Cherniak et al., 2022; Nie et al., 2022; Pi et al., 1997; Zhao et al., 2021). The main reason for deriving these indices is due to unavailability of high cadence data.…”

On the Global Kinematic Positioning Variations During the September 2017 Solar Flare Events

“…When multiple CSs are detected simultaneously, the number of the unknown parameters increases. Hence, the redundancy of observations decreases, ultimately weakening the estimation of all unknowns and deteriorating the positioning accuracy and stability (Nie et al., 2022a, 2022b). To verify such hypothesis, we loosen the CS threshold of the PGF combination from 0.05 m (0.48 TECU) to 0.20 m (1.92 TECU), and the results during the X2.2, X9.3, and the X8.2 SFs were depicted from Figures 11–14.…”

Studying the Fixing Rate of GPS PPP Ambiguity Resolution Under Different Geomagnetic Storm Intensities

“…This influx of energy takes the form of enhanced electric fields, currents, and energetic particle precipitation disturbs the ionosphere through high‐latitude ionization, Joule and particle heating, ion‐drag forcing, and disturbed electric field penetration, producing ionospheric storms characterized by enhancements or depletions of the ionospheric electron density (Buonsanto, 1999; Yang et al., 2020). The research and understanding of ionospheric disturbances caused by geomagnetic storms hold practical significance for human activities such as communication, positioning, navigation, and timing using Global Navigation Satellite System (GNSS), as well as other applications related to space weather (Förster & Jakowski, 2000; Nie et al., 2022).…”

“…tioning, navigation, and timing using Global Navigation Satellite System (GNSS), as well as other applications related to space weather (Förster & Jakowski, 2000;Nie et al, 2022).…”