# Assessment of BeiDou-3 and Multi-GNSS Precise Point Positioning Performance
## 6 Conclusions  
As of 1 April 2019, the 33 BDS satellites and 26 Galileo satellites can currently transmit the health signals for users. BDS and Galileo have been transformed into stable and reliable global navigation systems, which can provide global precise services. Therefore, it is meaningful to evaluate the ability of global PPP of the GPS, BDS, GLONASS, Galileo, and multi-GNSS. The performance of the GPS, BDS-2, BDS-2/BDS-3, GLONASS, Galileo, and multi-GNSS were analyzed in terms of PDOP, positioning accuracy, convergence time, and ZTD accuracy. Especially, the contribution of BDS-3 to multi-GNSS was analyzed to identify the performance of BDS. In the geographic area of the selected station, the conclusions are listed, as follows. The current BDS and Galileo are not regional navigation systems, but global navigation systems. They are basically capable of global precise positioning and the BDS-2/BDS-3 and Galileo PDOP values are fairly evenly distributed around the world, as seem as GPS and GLONASS. There is no significant difference between GPS, BDS, GLONASS, and Galileo from the perspective of the positioning accuracy and convergence time. The static BDS-2/BDS-3 PPP improves the positioning accuracy by 17.05%, 24.42%, and 35.65% and reduces the convergence time by 27.15%, 27.87%, and 35.76% over the BDS-2-only PPP in three coordinate components, respectively. The RMS of the global position errors for static BDS-2/BDS-3 PPP and Galileo-only PPP are 10.7, 19.5, 20.4 mm and 6.9, 18.6, 19.6 mm, respectively, as the same level as GPS and GLONASS. The GPS/BDS-2/BDS-3 and GPS/Galileo PPP achieves slightly better performance than GPS/GLONASS PPP. Similar to the static PPP, the kinematic BDS-2/BDS-3 PPP improves the position accuracy by 26.32%, 36.00%, and 35.94% and reduces the convergence time by 19.32%, 14.07%, and 19.86% over the BDS-2-only PPP in three coordinate components, respectively. The effect of multi-GNSS to improve the positioning accuracy and the reduce convergence time is more obvious in kinematic positioning. GPS/BDS-2/BDS-3 and GPS/Galileo PPP are both better than GPS-only PPP in terms of kinematic positioning accuracy and convergence time. The multi-GNSS PPP further increases the positioning accuracy and decreases the convergence time over the single-constellation and dual- constellation PPP in both static and kinematic PPP. The BDS-2/BDS-3 PPP accuracy improves the ZTD by 13.16% over the BDS-2-only PPP and there is no significant difference between GPS, BDS, GLONASS, and Galileo. Moreover, the GLONASS PPP and Galileo PPP are slightly poorer than the BDS-2/BDS-3 PPP. Regarding the multi-GNSS, the GPS/BDS-2/BDS-3, GPS/GLONASS, GPS/Galileo, BDS-2/BDS-3/GLONASS, BDS-2/BDS-3/Galileo, GLONASS/Galileo, and GPS/BDS-2/BDS-3/GLONASS/Galileo PPP improve the ZTD accuracy by 1.52%, 4.55%, 1.52%, 1.52%, 0.76%, and 6.06% over GPS-only PPP. The contributions of BDS and Galileo to multi-GNSS are significant. In summary, the new generation BDS is basically capable of global PPP. Its coverage and positioning performance are significantly improved when compared with BDS-2, and the difference is significantly reduced as compared with GPS, GLONASS. Galileo has also made good progress in terms of the coverage and precise positioning. BDS and Galileo are basically at the same level as GPS and GLONASS, and they can be well applied to global precise positioning and other application. [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] conceived and designed the experiments; [PERSON] performed the experiments, analyzed the data, and wrote the paper; [PERSON], [PERSON], [PERSON], and [PERSON] contributed to discussions and revisions. **Funding:** This work is supported by National Key R&D Program of China (2016 YFB0501503-3). **Acknowledgments:** The authors gratefully acknowledge WHU for providing GPS, BDS-2, BDS-3, GLONASS and Galileo precise orbit and clock products. Many thanks to the IGS for providing the tropospheric products.