多模多频GNSS系统间偏差的统一函数模型与估计方法研究

Differential inter-system bias (DISB) is one of the major errors that must be considered in tightly combined relative positioning with multi-GNSS. Conventional carrier DISB processing models are mainly for overlapping frequencies and short baselines, and thus difficult to effectively compatible with current mixing processing of multi-system and multi-frequency signals. For this problem, the project intends to research the unified function model of inter-system bias and break through the fast estimation of carrier DISB, so that the model can be applicable to mixing processing of multi-system and multi-frequency signals, and thus tightly combined high-precision positioning can be implemented. The specific ideas are as follows: the rank-defect problem among DISB, receiver clock, ambiguity, ionosphere delay and other parameters will be studied first, so that a full-rank single-difference un-combined observation model can be founded. On this basis, by fixing the intra-system double-difference ambiguity, the fast estimation method of carrier DISB with the constraint of integer ambiguity will be researched. Finally, step-by-step integer constraint for extra-wide-lane, wide-lane and narrow-lane is implemented on the unified function model, so that a progressive tightly combined positioning model can be established. The project is expected to solve the problem of tightly combined mixing processing of multi-GNSS observations. This will be of theoretical significance to the deep fusion of multi-GNSS, and thus beneficial to improve the high-precision positioning performance in harsh environments.

差分系统间偏差（DISB）是多模GNSS紧组合相对定位中必须考虑的误差因素之一，常规载波DISB处理方法主要面向重叠频率及短基线，难以有效兼容当前多模多频混合处理情况。为此，项目拟研究适用于多模多频混合处理的系统间偏差统一函数模型，重点突破载波DISB的快速估计技术，实现紧组合基础上的高精度定位。具体思路为：研究DISB与接收机钟差、模糊度、电离层等参数间的秩亏问题，构建满秩的站间单差非组合统一观测模型；在此基础上，通过系统内模糊度的分离和固定，构建附有整数模糊度约束的载波DISB快速估计方法；最后，在统一的函数模型上实施超宽巷-宽巷-窄巷的分步整数约束，建立精度渐进的紧组合定位模型。项目研究有望解决多模多频GNSS观测信息混合紧组合处理的难题，对于促进多模多频GNSS的深度融合和复杂观测环境下高精度定位的性能提升具有理论意义。

围绕GNSS高精度定位在复杂环境下的可靠定位需求，项目以多模多频GNSS系统间偏差处理为研究对象，致力于解决多GNSS数据的紧组合处理。围绕研究目标，主要开展了以下三方面内容研究：首先建立了基于站间单差非组合的系统间偏差参数函数模型，实现系统间偏差参数的满秩可估，并相应提出和发展了长基线系统间偏差模型；其次针对系统间偏差参数的估计问题，通过重参化实现系统内双差模糊度的整数可估性，在此基础上通过粒子滤波方法实现复杂环境下的DISB参数快速估计；最后提出了发挥多模多频信号优势的多种快速定位模型，包括基于超宽巷/宽巷组合的中长基线单历元定位方法和网络RTK紧组合定位方法，提升了定位的实时性和可靠性。项目完成了预期研究目标，形成了一套较为完善的多模多频系统间偏差数据处理方法。基于项目成果发表学术论文16篇（其中包含SCI论文9篇，EI论文4篇），申请发明专利6项（其中授权2项），培养了江苏省科协“青年科技人才托举工程”培养对象1人次，博士研究生2名、硕士研究生2名。项目研究作为组成部分之一，获得中国卫星导航定位协会科技进步一等奖。研究成果对于提升GNSS在复杂观测环境下定位模型的强度进而提升定位精度和可靠性具有重要的理论意义和实用价值。