基于多参数模型的实时精密单点定位理论与方法研究

To reduce the service item and improve the independent ability of single receiver, a new strategy to realize the real-time precise point positioning in triple-frequency observations is presented, and the theory of multi-parameter model based real-time precise point positioning is constructed in this project. The capability of real-time data pre-processing is improved through studying of the pre-processing method of triple-frequency observations. The algorithms of fast estimation, precise prediction and model of the inter-frequency bias are studied. In order to enable a consistent use of the satellite clock of different observation combinations, the algorithms are used to compute and correct inter-frequency bias. Based on the consistency, the multi-parameter model of real-time precise point positioning is studied and built. The key issues of parametric convergence time are studied to present the strategy to fix the un-differenced ambiguity and realize the fast and precise positioning of multi-parameter model based real-time precise point positioning. The multi-parameter model based real-time precise point positioning can be implemented through studying of the above theories and algorithms. The positioning tchnology and related businesses will be changed by the performances of the multi-parameter model based real-time precise point positioning.

为了简化精密单点定位的服务内容，增强单站观测的自主能力，本项目提出了采用三频观测数据的多参数实时精密单点定位理论。主要研究三频观测信号的实时预处理方法，提高系统的预处理能力；研究三频信号频间差异快速估计，及高精度预报、模型化的相关算法。通过对三频信号频间差异的精密计算与归化，使不同观测组合对应的卫星钟差补偿具有一致性；基于各观测组合对应卫星钟差的一致性，构建多参数实时精密单点定位模型；分析影响多参数模型参数收敛时间的因素，研究参数快速收敛的有效解决方案，实现高精度定位。通过相关理论与方法系统、全面地研究，实现多参数实时精密单点定位。多参数实时精密单点定位的实现，无疑会给导航定位技术及相关产业带来重要性的变化。

为了减轻对PPP 的服务负担，简化服务内容，减少PPP 对外界的依赖性，构建基于多参数模型的实时PPP 的相关理论与算法具有重要的意义。第三频率观测信号的应用，增加了更多的观测量，为多参数实时PPP 的实现提供了前提条件。本项目系统全面地研究、分析了采用三频观测组合时，频间差异变化与单个信号变化的关系；根据不同导航系统频间差异的特点、变化率，研究了其对数据预处理的影响，并结合双频观测预处理已有算法，形成了三频观测数据的实时预处理方案。研究了估计频间差异时，参数的消去算法及对应模型，达到快速估计的目的。采用了历元间差分技术，消去了模糊度参数对于频间卫星钟差偏差的影响，大大减少了估计参数的个数，提高了解算速度。针对各种估计方法的不足，提出了采用相位、伪距两种观测进行高精度频间卫星钟差偏差的估计算法。结合不同导航系统，分析了频间差异产生的渊源及其变化规律，然后进行高精度预报和模型化。分析了GPS、北斗系统观测中存在的频间钟差偏差特性，初步建立了基于4阶谐函数的频间钟差偏差模型，对应模型化精度可以达到2 cm。在现有PPP 模型基础上，增加估计参数个数，即增加卫星钟差为估计参数，与观测量进行对比，研究多参数模型的可行性。结合参数估计理论，进行了多参数实时PPP 模型的评估和论证，研究各参数的可估性及对应的处理方案，最后建立了多参数实时PPP 模型。