Real-time high-rate seismogeodesy using Galileo HAS and BDS PPP-B2b products: a shake table experiment and application to the 2024 Mw 7.0 Wushi earthquake

Summary High-rate GNSS is a valuable seismogeodetic tool for real-time monitoring of seismic displacements. The BeiDou PPP-B2b service provides precise point positioning (PPP) augmentation corrections via the B2b signal for BDS-3 and GPS satellites, while the Galileo High Accuracy Service (HAS) delivers such corrections for GPS and Galileo satellites via the E6B signal. However, PPP-B2b and HAS services are designed for different constellations, which makes the simultaneous use of BDS-3, Galileo, and GPS impossible through a single service. To fully exploit the capabilities of multi-GNSS, we propose a method to integrate the PPP-B2b and HAS products with the emphasis on the positioning performance gain of the integrated products under high-rate and short-time seismogeodetic environment. In the simulated seismic wave experiments, PPP-B2b and HAS achieve positioning accuracies of 4.2 cm and 5.2 cm, respectively. For the 2024 Mw 7.0 Wushi earthquake, PPP-B2b attains accuracies of 0.50 cm, 0.94 cm, and 1.10 cm, while HAS achieves comparable accuracies of 0.83 cm, 0.67 cm, and 1.55 cm in the east, north, and up components, respectively. Compared with standalone product, the integrated solution improves positioning accuracy by an average of 21% in the single-axis shake table experiment and by 42%, 29%, and 45% during the Wushi earthquake, achieving average accuracy of 0.37 cm, 0.58 cm, and 0.69 cm in the east, north, and up components, respectively. Magnitudes for the Wushi earthquake derived from the peak ground displacement of GNSS seismic waveforms using the PPP-B2b, HAS, and integrated products show good agreement with the WUM product. These results confirm the feasibility of PPP-B2b, HAS, and particularly their combined use for high-precision positioning, highlighting their great potential for real-time seismogeodetic applications in regions with limited communication infrastructure.