GPS/BDS伪距/相位偏差的产生机制及其对精密单点定位整周模糊度固定的影响研究

Integer ambiguity resolution has been proven to significantly shorten the convergence time of precise point positioning (PPP), whose key is the isolation of the code/phase biases, the clock error and the phase ambiguity. Several GPS PPP integer ambiguity resolution models based on combined and uncombined observables have been developed during past nine years. However, limited efforts have been made to explore the mechanism of the code/phase biases and the relationship among the developed methods. This project proposes to explore the mechanism of code/phase biases within the software receiver. Based on adjustments of the local reproduced pseudo random code rate and carrier phase frequency, the satellite code phase and carrier phase signals can be locked and then the mechanism of code/phase biases is investigated accordingly. The relationship among the combined and uncombined PPP integer ambiguity resolution models and the transformation of their corrections are studied afterwards. Finally, the PPP integer ambiguity resolution theory based on GPS will be extended to that based on GPS/BDS, and the GPS/BDS PPP integer ambiguity resolution methods will also be derived. Research achievements of this project will be of great scientific significance and practical value for the GPS/BDS PPP integer ambiguity resolution theory, the user implementation and the performance optimization.

整周模糊度固定可以显著缩短精密单点定位PPP的收敛时间，其关键技术是伪距/相位偏差、时钟误差和相位模糊度的分离。目前已提出了多种GPS无电离层组合和非组合PPP整周模糊度固定模型，但在伪距/相位偏差的产生机制、各种模型的内在联系等方面的研究有限。本项目提出从软件接收机内部研究伪距/相位偏差的产生机制，通过调整本地复现的伪随机码的码速率和载波频率，实现对输入信号的码相位和载波频率的锁定，达到探索伪距/相位偏差产生机制的目的。在此基础上，研究和推导各种GPS组合和非组合PPP整周模糊度固定模型的内在联系和模型改正数的相互转换。最后，将GPS单星系统理论扩展到GPS/BDS双星系统，建立GPS/BDS双星组合和非组合PPP整周模糊度固定模型。本项目对于GPS/BDS PPP整周模糊度固定理论、用户算法实现和性能优化具有科学意义和实用价值。

GPS/BDS伪距/相位偏差参数、钟差参数以及模糊度参数的分离是精密单点定位（PPP）中模糊度固定的关键，项目对伪距/相位偏差产生机制、分离方法及模糊度固定方法进行了研究。.1）基于自主开发的GPS、GPS/BDS软件接收机，给出了接收机伪距/相位偏差的产生机制；.2）针对目前三种主要的组合PPP整周模糊度固定模型（Single-difference between satellites, Decoupled clock, Integer phase clock），推导出GPS无电离层组合PPP中整周模糊度与伪距/相位偏差、伪距/相位偏差与时钟误差之间的关系，证明了三种模糊度固定模型的等价性，并将GPS组合PPP模糊度固定模型推广至GPS非组合PPP模型；.3）将传统GPS单星双频组合/非组合模糊固定模型推广至GPS/BDS双星五频组合/非组合PPP，建立了双星系统下的PPP整周模糊度固定模型。..项目共发表学术论文8篇，其中SCI/EI各5/1篇；项目负责人获2017年测绘科技进步奖特等奖1项（排名4）。