首先证明了非差网络实时动态定位(real time kinematic,RTK)与广域精密单点定位(precise point positioning,PPP)-RTK用户模糊度解算结果的一致性,并利用前者的模糊度可快速固定而后者无需用户与基准站间实时数据通讯的特性,提出了一套适用于大规模用户的非差网络RTK服务模式。按照新模式处理了湖北省连续运行参考站系统的一组实时数据,并与采用原有服务模式的解算结果进行比较,定量评估了新服务模式在实时应用中的定位精度及可靠性。结果表明,对于基准站间平均距离约为120km的区域增强网,网内用户一般只需几个历元进行初始化,便可获得平面方向1-2cm、高程方向6.3cm的快速实时精密定位服务;并且一旦用户完成模糊度初始化,区域增强系统可同时服务的用户数量将不再受限制;与采用原有非差网络RTK模式时94.274%的服务有效性相比,新模式的服务有效性高达99.914%,有效填充了原有服务模式下由于用户周边基准站区域增强信息中断引起的“服务空隙”。
In this contribution, we show the ambiguity consistency between an undifferenced network RTK (URTK) and wide-area PPP-RTK. We make full use of rapid ambiguity fixing in URTK and the lack of the need for real-time communication between users and reference stations in wide-area PPP- RTK, to develop a new scheme to provide URTK services. It is a hard task for existing URTK to realize real-time rapid precise positioning easily for massive numbers of users. Positioning precision and the availability for the proposed scheme and the old one were validated with the real-time data from HBCORS in China. Test results verify that, for a reference network with a station separation of about 120 km, user ambiguities can be fixed in several epochs, with real-time positioning precision for a user in the horizontal and vertical directions are 1 to 2 cm and 6.3 cm, respectively. Once the user ambiguities are successfully fixed, the new URTK service can support an almost unlimited number of users. In comparison with the 94.27% service effectiveness of the existing URTK scheme, the new scheme can fill these service gaps and provide users with more reliable and continuous service.