Global Ionospheric Modelling using Multi-GNSS: BeiDou, Galileo, GLONASS and GPS

Area of Science:

• Geodesy
• Space Physics
• Satellite Navigation

Background:

• The proliferation of Global Navigation Satellite Systems (GNSS) beyond GPS, including GLONASS, BeiDou, and Galileo, has increased the density of ionospheric piercing points (IPPs).
• This increased IPP coverage presents significant opportunities for developing high-resolution Global Ionospheric Maps (GIMs).
• Improved GIMs are crucial for enhancing the accuracy of positioning services and advancing ionospheric monitoring.

Purpose of the Study:

• To develop and evaluate Global Ionospheric Maps (GIMs) using multi-GNSS observations.
• To analyze the performance and contribution of integrating multiple satellite constellations (GPS, GLONASS, BeiDou, Galileo) for ionospheric modeling.
• To assess the impact of multi-GNSS GIMs on single-frequency precise point positioning (SF-PPP) accuracy.

Main Methods:

• Processing multi-GNSS observations from over 300 stations across the Multi-GNSS Experiment (MGEX) and International GNSS Service (IGS) networks over two months.
• Developing GIMs based on combined data from GPS, GLONASS, BeiDou, and Galileo.
• Analyzing Differential Code Biases (DCBs) as by-products of the multi-GNSS ionosphere modeling process.

Main Results:

• Multi-GNSS GIM products demonstrate superior performance compared to GPS-only GIM products.
• Satellite DCB standard deviations were 0.06 ns (GPS), 0.10 ns (GLONASS), 0.18 ns (BeiDou), and 0.15 ns (Galileo).
• Receiver DCB standard deviations ranged from approximately 0.2 to 0.4 ns.
• Single-frequency precise point positioning (SF-PPP) results showed improved ionospheric modeling accuracy with multi-GNSS GIMs compared to dual-system GIMs in specific regions.

Conclusions:

• Integrating multi-GNSS observations significantly enhances the accuracy and resolution of Global Ionospheric Maps.
• The developed multi-GNSS GIMs provide a more robust foundation for ionospheric monitoring and precise positioning applications.
• The study confirms the benefits of multi-constellation GNSS for ionospheric modeling and its positive impact on single-frequency positioning accuracy.