Abstract
The third generation of China’s BeiDou Navigation Satellite System (BDS-3) began to provide global service at the end of 2018, and the completion of BDS was announced in July 2020, which includes GEO (Geostationary Earth Orbit), IGSO (Inclined Geosynchronous orbit), and MEO (Medium Earth Orbit) satellites. The resulting BDS orbits vary due to the inconsistent alignment strategies used by different analysis centers. Therefore, it is necessary to study the method of determining the BDS-3 orbit products combined from different analysis centers. In this research, the accuracy of the combined orbits for BDS-3 and other GNSS systems is evaluated and analyzed. To verify the reliability of the orbit combination method proposed in this paper, the GPS orbit is first selected for verification. Compared to the analysis centers, the mean Signal in Space User Ranging Error (SISURE) for GPS combined orbits is significantly reduced, and the mean SISURE of combined orbits for Block IIF, Block IIR, and Block III is 4.15 mm, 5.43 mm, and 5.63 mm, respectively. This demonstrates the effectiveness of the orbit combination method in this research. Besides, the accuracy of the combined orbits is improved by the ERP correction, and the mean RMS of the without Earth rotation Parameters (ERP) correction orbits and with ERP correction orbits is 4.78 mm and 4.53 mm, respectively. This demonstrates that orbit consistency corrections should be considered when performing orbit combinations. Compared to the GFZ orbits, the accuracy of the combined orbits has improved for GPS, GLONASS, GALILEO, and BDS is 8.2%, 9.9%, 9.9%, and 5.5%, respectively. It shows that the orbit combination method improves the orbital accuracy compared to the individual analysis center orbits. The mean RMS of the combined orbits for GPS, GLONASS, GALILEO, BDS MEO, and BDS IGSO is 1.7 cm, 2.61 cm, 2.52 cm, 2.59 cm, and 4.90 cm, respectively. The results demonstrate that the accuracy of the combined orbit for the BDS-3 MEO satellite is already similar to other systems; an orbit combination also available for the BDS-3 satellite.
Funder
Key Project of China National Programs for Research and Development
National Natural Science Foundation of China
Opening Project of Shanghai Key Laboratory of Space Navigation and Positioning Techniques
State Key Laboratory of Geo-Information Engineering and Key Laboratory of Surveying and Mapping Science and Geo-spatial Information Technology of MNR, CASM
Scientific Research Project of Chinese Academy of Surveying and Mapping
Subject
General Earth and Planetary Sciences
Reference41 articles.
1. Multi-GNSS high-rate RTK, PPP and novel direct phase observation processing method: Application to precise dynamic displacement detection;Paziewski;Meas. Sci. Technol.,2018
2. Siejka, Z. (2018). Validation of the accuracy and convergence time of real time kinematic results using a single galileo navigation system. Sensors, 18.
3. Comparative analysis of active geodetic networks in Poland;Specht;Int. Multidiscip. Sci. GeoConference SGEM,2017
4. Assessment of precise orbit and clock products for Galileo, BeiDou, and QZSS from IGS Multi-GNSS Experiment (MGEX);Guo;GPS Solut.,2017
5. Robert, W., and Elisabeth, F. (1999, January 13–14). In Proceedings of the Combined GLONASS Orbits, IGS International GLONASS Experiment IGEX-98 Workshop Proceedings, Nashville, TN, USA.