Abstract To realize the smooth transition from regional BeiDou Navigation Satellite System (BDS-2) to the global one (BDS-3), the integration of BDS-2 and BDS-3 is important for providing continuous, stable and reliable positioning, navigation and timing (PNT) services for global users. This work used 154 globally distributed multi-GNSS (Global Navigation Satellite System) experiment stations spanning 30 days to analyze the satellite availability and positioning performance of uncombined precise point positioning (UC-PPP) under current BDS-2 and BDS-3 constellations. We focused on three issues: the influence of BDS-3 receiver tracking abilities, the positioning performance among different areas, and the benefit of multi-frequency observations. The results show that the elliptical zone caused by poor BDS-2 satellite visibility is disappeared when the evenly distributed BDS-3 medium earth orbit satellites are introduced. When BDS-3 are integrated with BDS-2, the area with the Position Dilution of Precision (PDOP) less than 2 can be expanded to 75° S-75° N and 30° E-150° W. The positioning performance of BDS-3 and BDS-2/BDS-3 UC-PPP are seriously affected by the receiver tracking abilities of BDS-3 signals. When the maximum pseudo-random noise sequences (PRNs) of BDS-3 satellites tracked by stations are within 30 or 37, the positioning accuracy of static UC-PPP can be improved by 22.94% or 8.27 % due to the integration of BDS-2 and BDS-3. Besides, the most improvement of BDS-2 and BDS-3 integration is achieved in Asia-Pacific regions, especially for the kinematic UC-PPP or the poor receiver tracking abilities of BDS-3. Similar to the multi-frequency BDS-2 UC-PPP, the benefit of multi-frequency signals for BDS-3 or BDS-2/BDS-3 UC-PPP is also non-vital. The three-dimensional positioning accuracy of BDS-2/BDS-3 multi-frequency UC-PPP in static mode and kinematic mode are 2.24 cm and 5.39 cm, while the corresponding convergence time are 49.62 min and 73.80 min, respectively. Compared with BDS-2, both the positioning accuracy and the convergence time of BDS-2/BDS-3 joint UC-PPP are improved by approximately over 50%, which indicates that BDS-3 has a great potential to provide high-quality PNT services as other global navigation satellite systems.

中文翻译：

---

使用北斗二号和北斗三号多频信号的非组合精确点定位的卫星可用性和定位性能

摘要 为实现区域北斗卫星导航系统（BDS-2）向全球卫星导航系统（BDS-3）的平稳过渡，BDS-2和BDS-3的集成对于提供连续、稳定、可靠的定位、导航和导航具有重要意义。面向全球用户的计时 (PNT) 服务。这项工作使用了 154 个全球分布式多 GNSS（全球导航卫星系统）实验站，为期 30 天，分析了当前 BDS-2 和 BDS-3 星座下未组合精确点定位（UC-PPP）的卫星可用性和定位性能。我们关注三个问题：BDS-3 接收机跟踪能力的影响、不同区域之间的定位性能以及多频观测的好处。结果表明，引入均匀分布的北斗三号中地球轨道卫星后，北斗二号卫星能见度差造成的椭圆带消失。BDS-3与BDS-2集成后，PDOP小于2的区域可扩展到75°S-75°N和30°E-150°W。 北斗定位性能-3 和 BDS-2/BDS-3 UC-PPP 受到 BDS-3 信号接收跟踪能力的严重影响。当台站跟踪的BDS-3卫星最大伪随机噪声序列(PRNs)在30或37以内时，由于BDS-2的集成，静态UC-PPP的定位精度可提高22.94%或8.27%和 BDS-3。此外，BDS-2 和 BDS-3 集成的最大改进是在亚太地区，特别是对于运动学 UC-PPP 或 BDS-3 较差的接收机跟踪能力。与多频 BDS-2 UC-PPP 类似，多频信号对 BDS-3 或 BDS-2/BDS-3 UC-PPP 的好处也不重要。BDS-2/BDS-3多频UC-PPP在静态模式和运动模式下的三维定位精度分别为2.24 cm和5.39 cm，相应的收敛时间分别为49.62 min和73.80 min。与BDS-2相比，BDS-2/BDS-3联合UC-PPP的定位精度和收敛时间均提高了约50%以上，表明BDS-3具有提供高质量PNT的巨大潜力服务作为其他全球导航卫星系统。多频信号对 BDS-3 或 BDS-2/BDS-3 UC-PPP 的好处也不重要。BDS-2/BDS-3多频UC-PPP在静态模式和运动模式下的三维定位精度分别为2.24 cm和5.39 cm，相应的收敛时间分别为49.62 min和73.80 min。与BDS-2相比，BDS-2/BDS-3联合UC-PPP的定位精度和收敛时间均提高了约50%以上，表明BDS-3具有提供高质量PNT的巨大潜力服务作为其他全球导航卫星系统。多频信号对 BDS-3 或 BDS-2/BDS-3 UC-PPP 的好处也不重要。BDS-2/BDS-3多频UC-PPP在静态模式和运动模式下的三维定位精度分别为2.24 cm和5.39 cm，相应的收敛时间分别为49.62 min和73.80 min。与BDS-2相比，BDS-2/BDS-3联合UC-PPP的定位精度和收敛时间均提高了约50%以上，表明BDS-3具有提供高质量PNT的巨大潜力服务作为其他全球导航卫星系统。