基于BDS/GPS和经验模型的区域电离层建模

基于北斗卫星导航系统（BDS）和全球定位系统（GPS）实测电离层穿刺点（IPP）数据，结合国际参考电离层（IRI）经验模型历史数据，提出一种对区域二维电离层总电子含量（TEC）进行高精度建模的方法.针对缺乏穿刺点的区域内短时间电离层建模时精度较低且各时段穿刺点空间分布不同的问题，该方法使用IRI模型在建模区域内均匀添加虚拟穿刺点数据，并根据与实测穿刺点的距离，使用构造的权重计算公式赋予其动态权重值，通过加权最小二乘法进行球谐模型参数解算.与欧洲定轨中心（CODE）发布的全球电离层图（GIM）进行数据比对发现，相对于只使用BDS/GPS实测穿刺点数据的建模方法，利用本文建模方法计算获得的垂直总电子含量（VTEC）值对缺乏实测穿刺点的区域精度有明显的提升. 

Regional Ionosphere Modeling Based on BDS/GPS and Empirical Model

Based on the Ionospheric Pierce Point(IPP) data observed by the Beidou Navigation Satellite System(BDS) as well as Global Positioning System(GPS) and the historical data,a high accuracy modeling method for the Total Electron Content(TEC) of regional two dimensional ionosphere is proposed.The historical data are derived from International Reference Ionosphere(IRI)empirical model.The method can solve the low accuracy problem of short-period ionosphere modeling in the area lacking IPPs and the diverse distribution of IPPs in each period.Virtual IPP data estimated from the IRI model is uniformly inserted in the modeling area,and the dynamic weight value is assigned to the data using the constructed weight calculating formula according to the distance from the measured IPP.The spherical harmonic model parameters are calculated by the weighted least squares method.Based on the Global Ionosphere Map(GIM) released by Center for Orbit Determination in Europe(CODE),the comparison of the vertical TEC value obtained from this present method with the modeling method only using BDS/GPS IPP data shows that a significant accuracy improvement of the area lacking the measured IPP has been obtained by the method in this paper.