The accuracy of GNSS is essential for applications requiring precision, but regional networks often encounter challenges in maintaining this accuracy. By combining LEO satellite data with ground station measurements, a promising solution to these challenges has been identified. This approach highlights the need to explore more effective methods for GNSS orbit determination.
Researchers from the Shanghai Astronomical Observatory, Chinese Academy of Sciences, published a study on August 12, 2024, in 'Satellite Navigation' (DOI: 10.1186/s43020-024-00147-4). The study details how the integration of regional ground station data with LEO satellite measurements can significantly enhance GPS orbit determination. Data from January 20 to 26, 2019, involving 13 LEO satellites and six International GNSS Service stations across China, were analyzed. The findings suggest that this method can achieve centimeter-level accuracy in GPS orbit and clock products, which is essential for high-precision GNSS applications.
The study, conducted by the Shanghai Astronomical Observatory, focused on integrating measurements from 13 LEO satellites with data from six GNSS stations around China. The satellites involved included those from missions such as GRACE Follow-On, SWARM, Sentinel, Jason, and various Chinese meteorological satellites.
The results showed significant improvements in GPS orbit accuracy, with average errors reduced to 2.27 cm in the radial direction, 3.45 cm along-track, and 3.08 cm cross-track. Clock accuracy was also enhanced, with errors less than 0.15 nanoseconds. The LEO satellites themselves demonstrated high precision, with most errors within 4 cm. This approach underscores the potential of LEO satellites to boost GNSS accuracy, especially in regions where ground station coverage is limited, offering a reliable solution for achieving high-precision GPS orbit and clock products necessary for a variety of applications.
Dr. Chengpan Tang, the lead researcher from the Shanghai Astronomical Observatory, emphasized the importance of this study: "Integrating LEO satellite data with regional ground stations provides a practical solution to the challenges of high-precision orbit determination in GNSS. Our findings suggest that this approach can deliver reliable orbit and clock products, which are vital for a broad range of applications, from navigation to Earth observation."
The integration of LEO satellites with regional ground stations represents a major advancement in GNSS technology. This method not only improves GPS orbit determination accuracy but also opens up new opportunities for high-precision applications, particularly in areas with limited ground station coverage. As LEO satellite constellations continue to grow, this method could become a standard practice, ensuring more reliable and accurate GNSS services worldwide.