## 6 Conclusions  
The plan for global coverage by BeiDou was launched in 2015, and there are currently five next-generation satellites, named as BeiDou-3e, in orbit for validation and testing. Several iGMAS and GA stations were employed to analyze the characteristic performance of the original B1I and B3I signals via MP combinations in comparison with that of BeiDou-2 satellites in this study. As shown by our results, there was no obvious satellite-induced code bias for the next-generation BeiDou satellites, in contrast to the BeiDou-2 satellites. Using the real-valued ambiguity solution, the three-dimensional orbit consistency of BeiDou-2 GEOs, IGSOs, and MEOs reached 62 cm, 24 cm, and 23 cm, respectively, and the consistency of the radial component achieved 6 cm, 5 cm, and 5 cm, respectively. In comparison with BeiDou-2 satellites, the three-dimensional orbit consistency of BeiDou-3e IGSOs and MEOs reached 27 cm and 25 cm, respectively, and the consistency of the radial component achieved 7 cm and 5 cm, respectively. The ambiguity fixed solution was improved by about 10% in the along-track and cross-track components for IGSOs, but for MEOs the improvement was not noticeable. The results of SLR validation showed that, for BeiDou-2 satellites, the STD values for IGSOs ranged from 6.2 cm to 9.8 cm and STD for MEOs were about 6.8 cm, whereas for BeiDou-3e satellites, the STD values were 4 cm for MEOs and 9.6 cm for IGSOs. Furthermore, the clock quality was evaluated for BeiDou satellites, which indicated that the performance of clock products was in accordance with the orbit precision results.  
PPP performances were analyzed with different GPS/BeiDou satellite configurations. Static PPP results show that including BeiDou-3e satellites can slightly improve the horizontal precision for BeiDou only or GPS/BeiDou combined solutions. The post-mission kinematic PPP convergence time using only BeiDou-2 satellites was the longest at about 46 min, but when GPS satellites were included, the convergence time was greatly reduced to about 18.5 min. As our analytical results showed, the newly launched BeiDou-3e satellites could improve the positioning precision and convergence time owing to their better geometry. The convergence time for kinematic PPP when combing GPS, BeiDou-2 and BeiDou-3e data was reduced to 13.5 min.  
The results obtained in this study show that BeiDou-3e satellites can now achieve similar orbit and clock offset precision as BeiDou-2 satellites. By in-cooperating BeiDou-2 with BeiDou-3e satellites, the static and kinematic PPP performances are slightly improved. It is expected the BeiDou system can benefit the community much more after the whole global constellation is deployed.  
The authors are very grateful to iGMAS, GA, IGS-MGEX and ILRS for data supply. The authors would like to express thanks to the editors and the anonymous reviewers for their insightful and helpful comments and suggestions, which resulted in substantial improvements to this work. This work is supported by the National Natural Science Foundation of China under Grant [NOS 41574027, 41574030, 41774035] and the National Key Research and Development Program of China (Grant No. 2016 YFB0501800).  
**Author Contributions:** [PERSON] provided the initial idea for this study and supervised the analyses and revised this article. [PERSON] designed and performed the data analysis and wrote the article. [PERSON] helped with the writing and data tests. [PERSON] supervised the analyses and revised this article.  
**Conflicts of Interest:** The authors declare no conflict of interest.