【作者】 李施佳； 蔡昌盛； 戴吾蛟； 易志鹏；

【Author】 Li Shijia 1 , Cai Changsheng 1,2 , Dai Wujiao 1,2 , Yi Zhipeng 3 1. School of Geoscience and Info-Physics, Central South University, Changsha, China 2. Key Lab of Precise Surveying & Deformation Disaster Monitoring in Hunan Province, Changsha, China 3. Electric Power Marketing Department of Hunan Electrical Corporation Training Center, Changsha, China

【机构】 中南大学地球科学与信息物理学院； 湖南省精密工程测量与形变灾害监测重点实验室； 国网湖南省电力公司培训中心电力营销培训分部；

【摘要】 随着GNSS的发展,电离层已经成为影响导航定位精度的主要误差源之一。由于利用电离层层析技术可以得到电离层的三维甚至四维结构,故对GNSS电离层层析技术的研究已引起广泛的关注。在层析计算中通常采用迭代算法来解决层析矩阵秩亏问题,迭代重构算法是在提供初始值的情况下,通过迭代对有信号穿越的网格内的初始值进行逐步的修复,直到满足设置的迭代终止条件为止。在应用迭代重构算法进行电离层重构时,一种普遍的做法是利用国际参考电离层模型(IRI模型)获得电离层密度迭代初始值,但IRI模型作为一种经验电离层模型,精度较低。而NeQuick2模型作为一种半经验电离层改正模型,可以得到任意时刻给定点的电子密度,精度比IRI模型更高,故本文基于GNSS实测数据,利用NeQuick模型计算获得迭代重构算法的初始值。为了验证NeQuick模型的优越性,其层析结果与利用IRI模型获取迭代初始值的层析结果进行了比较。更多还原

【Abstract】 Ionosphere is one of the main error sources that affect the navigation and positioning accuracy. As the ionospheric tomography is capable of reconstructing 3-D and even 4-D ionospheric structure, the tomography technology has attracted abroad attention. In the process of ionospheric tomography, iterative reconstruction algorithm is commonly used to solve the matrix rank deficiency. But the accuracy of the iterative algorithm largely relies on the initial values. During the iterative process, the initial values of the grids that are passed by signals will be updated until the termination conditions are satisfied. When using the iterative algorithm to reconstruct ionosphere, the initial values are usually obtained from the International Reference Ionosphere (IRI) Model. However, the IRI Model is an empirical model and its accuracy is relatively low. By contrast, the NeQuick Model, which is adopted for Galileo ionospheric error corrections, is a semi-empirical model and has a higher accuracy. This paper uses initial values derived from NeQuick Model in the iterative reconstruction algorithm. The tomography results have been compared with the tomography results with initial values obtained from IRI Model.更多还原