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

Area of Science:

• Space Physics
• Geodesy
• Satellite Navigation

Background:

• Geomagnetic storms are space weather events that disrupt Earth's magnetic field.
• These disruptions can severely impact Global Positioning System (GPS) signal propagation and the accuracy of precise point positioning (PPP).
• Limited research exists on the global-scale performance of GPS PPP under various geomagnetic storm conditions.

Purpose of the Study:

• To investigate the performance of GPS dual-frequency (DF) and single-frequency (SF) PPP globally under different geomagnetic storm intensities.
• To analyze the impact of solar cycle 24 geomagnetic storms on GPS PPP accuracy using a large dataset.
• To identify the relationship between storm intensity, geographic location, and degradation in GPS PPP performance.

Main Methods:

• Utilized data from approximately 500 International GNSS Services (IGS) stations globally.
• Analyzed GPS DF and SF PPP performance during moderate, intense, and super geomagnetic storms.
• Generated global root mean square (RMS) maps and Rate of TEC Index (ROTI) maps to assess positioning accuracy and ionospheric disturbances.

Main Results:

• GPS PPP performance degradation was primarily observed at high latitudes and generally correlated with geomagnetic storm intensity.
• Three-dimensional RMS errors for high-latitude DF PPP increased from 0.163 m on quiet days to 0.393 m, 0.680 m, and 1.051 m during moderate, intense, and super storms, respectively.
• Mid- and low-latitude RMS errors showed less dependence on storm intensity, and GPS SF PPP consistently underperformed DF PPP.

Conclusions:

• Increased ionospheric disturbances during geomagnetic storms are the primary cause of degraded GPS PPP performance.
• These disturbances lead to inaccurate ionospheric corrections and increased cycle-slip occurrences, with cycle slips increasing by up to 69.57% during super storms.
• GPS PPP accuracy is significantly compromised during intense space weather events, particularly at higher latitudes.