精密单点定位以其灵活的定位方式而广受关注，其具有巨大的发展潜力和广阔的应用前景，然而，尚难满足广域范围内快速厘米级定位应用场景需求。BDS-3和Galileo四频观测数据的播发，为上述问题的解决提供了有效的数据支持并使之成为可能。本项目拟以实现广域单测站快速厘米级定位为目标，构建合理可行技术方案，并就如下关键问题进行重点研究：1）研究四频相位几何无关组合周跳检测量和四频相位/伪距组合周跳检测量特性，构建四频周跳检测量优选方案；2）优化相位小数偏差基准和独立模糊度基准选取策略，引入并行计算和单观测值迭代Kalman滤波，构建四频相位小数偏差快速网解模型；3）构建四频精密单点定位模糊度快速固定模型，逐级引入模糊度固定质量控制，挖掘四频观测值在模糊度固定方面的优势。项目的开展将有利于进一步完善多频多系统模糊度快速固定理论，为参考站稀疏地区的快速高精度位置服务提供有力的技术支持。

Precise point positioning, which has great development potential and broad application prospects, has gained wide attention due to its flexible positioning mode. However, it is still difficult to meet the requirements of fast centimeter-level positioning application scenarios in a wide area. The release of the BDS-3 and Galileo four-frequency observations provides effective data support and makes it possible to solve the above difficultly. This project aims at achieving fast centimeter-level positioning accuracy for single station in wide area, and constructs a reasonable and feasible technical scheme. The following key issues are focused on: 1) The characteristics of the constructed cycle-slip detections based on four-frequency geometry-free phase combination and four-frequency phase/pseudorange combination are analyzed, respectively, and then the optimal scheme of four-frequency carrier phase cycle-slip detections is formed; 2) The selection strategy of phase fractional cycle bias datum and independent ambiguity datum is optimized, and then the parallel computing and iterated Kalman filter based on single-observation are introduced to construct the network-based estimation model for four-frequency phase fractional cycle bias; 3) A fast precise point positioning ambiguity resolution scheme using four-frequency observations is constructed, and the quality control of ambiguity resolution is introduced step by step, mining the advantage of four-frequency observations in fast ambiguity resolution. This project and its achievements are not only helpful to further improve the theory of multi-frequency and multi-system fast ambiguity resolution, but also providing strong technical support for areas without dense reference stations to obtain fast and high-precision location-based services.