BDS-3精密单点定位在铁路勘测中的应用研究

为研究第三代北斗卫星导航系统（BDS-3,BeiDou Navigation Satellite System-3）精密单点定位技术（PPP,Precise Point Positioning）在铁路勘测应用中的可行性，文章推导了BDS-3任意双频非差非组合PPP通用函数模型，并采用该模型对BDS-3卫星B1I、B3I、B1C和B2a信号形成的5种双频组合进行PPP解算和性能分析，利用某铁路观测数据，对BDS-3进行PPP解算。结果表明，所有观测时段内可见卫星数约为7～11颗，空间位置精度因子（PDOP,Position Dilution of Precision）值约为2.0，可见卫星数较多，且空间几何分布良好；在静态和仿动态解算模式下，在水平和高程方向均可实现厘米级的定位精度。该研究可为BDS-3精密单点定位技术在铁路勘察中的应用提供参考。

BDS-3 precise point positioning applied to railway survey

In order to study the feasibility of BeiDou Navigation Satellite System (BDS)-3 Precise Point Positioning (PPP) in railway survey application, this paper used BDS-3 satellite observation data to deduce BDS-3 arbitrary dual-frequency undifferenced and uncombined PPP universal function model. By using this model, the paper carried out the PPP solutions and performance analysis of five dual-frequency combinations formed by BDS-3 satellite signals B1I, B3I, B1C and B2a, and used a railway observation data to calculate BDS-3 PPP. The results show that the number of visible satellites is about 7~11, and the spatial Position Dilution of Precision (PDOP) is about 2.0 during the observation period. The number of visible satellites is large and the spatial geometry distribution is good. BDS-3 can achieve centimeter-level positioning accuracy in both horizontal and elevation directions in static and pseudo-dynamic solution modes. This study can provide reference for the application of BDS-3 precision point positioning technology in railway survey.