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。