The Mechanism for GNSS‐Based Kinematic Positioning Degradation at High‐Latitudes Under the March 2015 Great Storm. Issue 6 (23rd June 2022)

• Record Type: Journal Article
• Authors: Nie, Wenfeng; Rovira‐Garcia, Adrià; Li, Mowen; Fang, Zhenlong; Wang, Yong; Zheng, Dunyong; Xu, Tianhe
• Is Part Of: Space weather. Volume 20:Issue 6(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-23
• Subjects: Space environment -- Periodicals; 551.509992
• DOI: 10.1029/2022SW003132
• Languages: English
• ISSNs: 1542-7390

Abstract

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. Plain Language Summary: Geomagnetic storm is one kind of extreme space weather events, which disturbs the radio communication and degrade the precision of the global navigation satellite system (GNSS). Much efforts have been made to study the ionospheric responses to different geomagnetic storms and its impact on the GNSS performances. During intense geomagnetic storms, the positioning accuracies for stations at high‐, middle‐ and low‐latitudes are likely to degrade. Particularly, the positioning errors are more severe for stations at high‐latitudes due to the more frequent cycle slip (CS) than those at middle‐ and low‐latitudes under the same storm. In this study, we found that the degraded positioning accuracy at high‐latitudes was not only related to the large rate of total electron content index (ROTI) variation but also to the large number of the CS. Particularly, we deduce that a large amount of the CSs was falsely detected under the conventional threshold of the CS detector. The results in the study 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 the geomagnetic storm, as long as the CSs can be well addressed. Key Points: Phase scintillation is more severe than the amplitude scintillation at high‐latitudes during the great storm The degraded positioning accuracy at high‐latitudes is related to the large number of falsely detected cycle slip (CS) satellites Precise positioning can be achieved at high‐latitudes under the geomagnetic storm, given that the CS problems are well addressed