多GNSS组合精密单点定位非差模糊度快速固定方法

Based on only dozens of reference stations, Precise Point Positioning (PPP) can achieve high precise positioning results globally. However, neither scientific research institutions nor business companies at home and abroad have resolved the problem of long initialization time required for PPP ambiguity fixing, which greatly undermine its feasibility for industrial applications. This project intends to provide theories and methods for integrating muti-GNSS (BDS/GPS/GLONASS) observations to shorten the ambiguity fixing time for PPP. Key issues for this project are as follows: ①develop a model to correct the systematic pseudorange bias for BDS and GLONASS system, such that PPP wide-lane ambiguity fixing can be achieved; ②develop an integer satellite clock estimation strategy considering satellite orbit errors to resolve the impact of the large orbit error of BDS satellites; ③model the inter system bias for the receivers, such that different GNSS systems can be combined in an unified model to perform PPP ambiguity fixing; ④develop an ambiguity acceptance test threshold determination method with controllable success rate, which is suitable for multi-GNSS PPP ambiguity fixing. By integrating multi-GNSS, we strive to shorten the long initialization time, and also to improve the correctly fixing rate for traditional PPP ambiguity fixing based on solo GPS. This project would provide new ideas for the engineering application of PPP, which have both important significance of scientific research and engineering application value.

精密单点定位技术（PPP）仅需几十个基准站即可实现全球范围的高精度实时定位，然而国内外科研机构以及商业公司均未能很好解决PPP模糊度首次固定时间较长的问题，导致PPP技术无法得到广泛应用。为此，本项目拟研究组合多模GNSS数据（北斗/GPS/GLONASS）实现PPP模糊度快速固定的方法，主要研究内容包括：①北斗和GLONASS系统性伪距误差建模；②顾及卫星轨道误差的整数卫星钟差估计；③多GNSS统一的PPP模糊度固定解算模型；④自适应选取阈值的PPP模糊度可靠性检验。通过对多模PPP模糊度固定的研究，拟解决目前基于单GPS系统的PPP模糊度固定时间较长、固定可靠性不高的问题，为PPP应用提供一些新的思路，具有重要的科学研究意义和工程应用价值。

精密单点定位技术（PPP）仅需几十个基准站即可实现全球范围的高精度实时定位，然而国内外科研机构以及商业公司均未能很好解决PPP模糊度首次固定时间较长的问题，导致PPP技术无法得到广泛应用。本项目研究了组合多模GNSS数据（北斗/GPS/GLONASS）实现PPP模糊度快速固定的方法，主要研究了北斗和GLONASS系统性伪距误差建模的问题，提升了北斗系统伪距观测值精度，并实现了基于不同种接收机的GLONASS系统PPP模糊度的固定。研究了顾及卫星轨道误差的整数卫星钟差估计方法，实现了北斗系统GEO、IGSO、MEO三种类型卫星的整数卫星钟差估计。研究了多GNSS统一的PPP模糊度固定解算模型，实现了不同频段（L1, L2, L5, B1, B2, B3, G1, G2, E1, E5a, E5b, E5a+b, E6）、不同信号体制（CDMA/FDMA）、不同星座（GEO、IGSO、MEO）卫星信号的统一数据处理。研究了基于动态ratio阈值的模糊度检验方法，提高了多GNSS系统下模糊度固定的性能。在上述理论方法研究的基础上，研制了多GNSS整数卫星钟差估计以及PPP模糊度固定软件系统一套，进行了相关算法的应用验证，为PPP技术的工程应用提供了理论和方法支撑。研究目标基本全面完成，发表已标注国家自然科学基金资助的SCI论文4篇。