The Barcelona ionospheric mapping function (BIMF) and its application to northern mid-latitudes
The Barcelona ionospheric mapping function (BIMF) and its application to northern mid-latitudes
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DOI：
10.1007/s10291-018-0731-0
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发表时间：
2018-04
期刊：
影响因子：
4.9
通讯作者：
Haixia Lyu;M. Hernández‐Pajares;Metin Nohutcu;A. García‐Rigo;Hongping Zhang;Jing-nan Liu
中科院分区：
文献类型：
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作者：
Haixia Lyu;M. Hernández‐Pajares;Metin Nohutcu;A. García‐Rigo;Hongping Zhang;Jing-nan Liu
提出了一种利用垂直总电子含量（VTEC）模型改进全球导航卫星系统（GNSS）电离层倾斜改正的简单方法。在许多GNSS应用中，需要映射功能来从VTEC（其可在全球电离层地图（GIM）中提供）转换为倾斜TEC（STEC）。典型的方法假设一个单一的电离层外壳具有恒定的高度，这是不现实的，特别是对于低海拔信号。为了减少相关的转换误差，我们提出了巴塞罗那电离层映射函数及其在北方中纬度地区的第一个实现（BIMF-nml）。BIMF基于VTEC顶部垂直电子含量分数（以下简称µ2）分布的气候预测。BIMF在实际应用中不需要外部数据，便于应用。为了评估其性能，我们使用直接从中纬度双频全球定位系统（GPS）接收器测量的STEC差值（所谓的dSTEC）值作为独立参考，这些接收器尚未用于评估VTEC GIM的计算。结果表明，使用BIMF提高了GIM STEC估计相比，单层假设。全球导航卫星系统国际服务组织和星基增强系统使用的制图功能就是这种情况。这一改进不仅适用于UPC GIM，2014年高达15%，而且特别适用于其他分析中心的GIM，例如CODE和JPL生产的GIM，分别高达32%和29%。
A simple way of improving the Global Navigation Satellite Systems (GNSS) slant ionospheric correction from Vertical Total Electron Content (VTEC) models is presented. In many GNSS applications, a mapping function is required to convert from VTEC, which may be provided in Global Ionospheric Maps (GIMs), to Slant TEC (STEC). Typical approaches assume a single ionospheric shell with constant height, which is unrealistic, especially for low-elevation signals. To reduce the associated conversion error, we propose the Barcelona Ionospheric Mapping Function and its first implementation at northern mid-latitudes (BIMF-nml). BIMF is based on a climatic prediction of the distribution of the topside vertical electron content fraction of VTEC (hereinafterµ2). BIMF is convenient to be applied since no external data are required in practice. To evaluate its performance, we use as independent reference the STEC difference (so-called dSTEC) values directly measured from mid-latitude dual-frequency Global Positioning System (GPS) receivers that have not been used in the computation of the VTEC GIMs under assessment. It is shown that the use of BIMF improves the GIM STEC estimation compared to the single-layer assumptions. This is the case for the mapping functions used by the International GNSS Service (IGS) and Satellite-Based Augmentation Systems (SBAS). This improvement is valid not only for the UPC GIMs, up to 15% for the year 2014, but especially for the GIMs of other analysis centers, such as those produced by CODE and JPL, up to 32 and 29%, respectively.