Assessing the Performance of GPS Precise Point Positioning Under Different Geomagnetic Storm Conditions during Solar Cycle 24.

Xiaomin Luo,Shengfeng Gu,Yidong Lou,Biyan Chen,Chao Xiong,Xueyuan Jin

doi:10.3390/s18061784

Abstract

The geomagnetic storm, which is an abnormal space weather phenomenon, can sometimes severely affect GPS signal propagation, thereby impacting the performance of GPS precise point positioning (PPP). However, the investigation of GPS PPP accuracy over the global scale under different geomagnetic storm conditions is very limited. This paper for the first time presents the performance of GPS dual-frequency (DF) and single-frequency (SF) PPP under moderate, intense, and super storms conditions during solar cycle 24 using a large data set collected from about 500 international GNSS services (IGS) stations. The global root mean square (RMS) maps of GPS PPP results show that stations with degraded performance are mainly distributed at high-latitude, and the degradation level generally depends on the storm intensity. The three-dimensional (3D) RMS of GPS DF PPP for high-latitude during moderate, intense, and super storms are 0.393 m, 0.680 m and 1.051 m, respectively, with respect to only 0.163 m on quiet day. RMS errors of mid- and low-latitudes show less dependence on the storm intensities, with values less than 0.320 m, compared to 0.153 m on quiet day. Compared with DF PPP, the performance of GPS SF PPP is inferior regardless of quiet or disturbed conditions. The degraded performance of GPS positioning during geomagnetic storms is attributed to the increased ionospheric disturbances, which have been confirmed by our global rate of TEC index (ROTI) maps. Ionospheric disturbances not only lead to the deteriorated ionospheric correction but also to the frequent cycle-slip occurrence. Statistical results show that, compared with that on quiet day, the increased cycle-slip occurrence are 13.04%, 56.52%, and 69.57% under moderate, intense, and super storms conditions, respectively.

Highlights

Geomagnetic storms, i.e., large-scale disturbances in the Earth’s near-space environment, are caused by the enhanced solar wind and its interaction with the magnetosphere–ionosphere–thermosphere system.According to the Dst index derived from near-equatorial geomagnetic measurement, the principal feature of a geomagnetic storm represents an obvious decrease of the horizontal intensity of Earth’s magnetic field followed by a recovery [1]
A comprehensive investigation of geomagnetic storms effects on GPS precise point positioning (PPP) has been presented in our study
DF PPP accuracy of most international GNSS services (IGS) stations is better than 0.15 m and 0.2 m in the horizontal and vertical components, respectively

Summary

Introduction

Geomagnetic storms, i.e., large-scale disturbances in the Earth’s near-space environment, are caused by the enhanced solar wind and its interaction with the magnetosphere–ionosphere–thermosphere system.According to the Dst index derived from near-equatorial geomagnetic measurement, the principal feature of a geomagnetic storm represents an obvious decrease of the horizontal intensity of Earth’s magnetic field followed by a recovery [1]. Geomagnetic storms, i.e., large-scale disturbances in the Earth’s near-space environment, are caused by the enhanced solar wind and its interaction with the magnetosphere–ionosphere–thermosphere system. A geomagnetic storm is characterized by an increased spatial decorrelation of ionosphere range delays and scintillation effects at both high- and low-latitudes [4]. The occurrence of equatorial irregularities including equatorial spread-F (ESF) and plasma bubbles (EPBs) is quite complicated since it is influenced by many factors such as the existence of prompt penetration, disturbance dynamo electric fields, and small increase of geomagnetic activity level, which are all known affect the vertical plasma drifts and dominate the Rayleigh-Taylor linear growth rate [7]. The occurrence equatorial irregularities during geomagnetic storms can induce the equatorial ionospheric scintillation. To GNSS users, ionospheric scintillation possibly leads to the occurrence of cycle-slip and even loss of signal tracking, degenerating the GNSS positioning and navigation accuracy [9,10,11]

Methods

Results

Discussion

Conclusion