电波科学学报  2019, Vol. 34 Issue (3): 322-329  DOI: 10.13443/j.cjors.2018042201. PDF

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Three-dimensional ionospheric electron density reconstruction by data ingestion of ground-based GNSS and COSMIC occultation measurements
China Research Institute of Radiowave Propagation, Qingdao 266107, China
Abstract: Accurate determination of the ionospheric real-time state plays an important role in radiowave information systems such as modern communication and satellite navigation system. To provide three-dimensional(3D) specification of the ionosphere electron density for current conditions, a new 3D ionospheric electron density reconstruction method is developed by data ingestion of ground-based global navigation satellite system(GNSS) and constellation observing system for meteorology, ionosphere and climate(COSMIC) occultation measurements. Based on the latest International Reference Ionosphere model (IRI-2016), IG index and Rz index of IRI-2016 are selected as the driving parameter. With Brent algorithm, optimal IG and RZ indices are obtained in two steps by data ingestion of ground GNSS and COSMIC occultation measurements. The comparison between reconstructed results and data of eight ionosonode stations in the European region indicates that the absolute mean error and standard deviation of the reconstructed ionospheric NmF2 were decreased by 33% and 29% respectively, while the reconstruction error of the ionospheric hmF2 decreased by about 55% and 30% respectively. Comparison results demonstrate the accuracy and effectiveness of the proposed method.
Keywords: ionosphere    electron density reconstruction    data ingestion    GNSS    COSMIC occultation

1 基于数据吸收技术的三维电子密度重构

 图 1 电离层TEC/hmF2随IG/Rz指数的变化 Fig. 1 The variation of the ionospheric TEC/hmF2 with the IG/Rz index

 ${\rm{\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}} \over R} z}} = \arg \min {\mathop{\rm var}} \left( {{h_{\rm{m}}}{{\rm{F}}_{2\;{\rm{mod}}}}({\rm{Rz}}) - {h_{\rm{m}}}{{\rm{F}}_{2\;{\rm{mes}}}}} \right).$ (1)

 $\widehat {\rm{I}}{\rm{G}}(\theta , \varphi ) = \arg \min \left( {{{{\mathop{\rm TEC}\nolimits} }_{{\rm{mod}}}}(\mathord{\rm{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}} \over R}} {\rm{z}}, {\rm{IG}}, \theta , \varphi ) - {\rm{TE}}{{\rm{C}}_{{\rm{mes}}}}(\theta , \varphi )} \right)$ (2)

 $\begin{array}{l} {N_{{\rm{e}}, {\rm{Recon}}}} = {N_{{\rm{e}}, {\rm{IRI}}}}({\rm{Year}}, {\rm{doy}}, {\rm{UT}}, \theta , \varphi , h, \\ \;\;\;\;\;\;\;\;\;\;\;\;\;\;{\rm{\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}} \over R} z}}, \widehat {\rm{I}}{\rm{G}}(\theta , \varphi )) \end{array}$ (3)

2 电离层三维电子密度重构 2.1 数据来源

 图 2 SPIDR在欧洲区域的8个垂测站地理位置分布 Fig. 2 Distribution of 8 SPIDR ionosondes in Europe
2.2 电离层三维电子密度重构结果

 图 3 2014年08月24日夜间UT 00:00时刻的电子密度重构的结果 Fig. 3 Ionospheric electron density reconstruction result at UT 00:00 on August 24, 2014
3 重构精度评估与分析 3.1 电离层NmF2重构精度比较

 图 4 八个台站数据吸收前后及垂测站的电离层NmF2比较 Fig. 4 Comparison of NmF2 before and after data ingestion of eight ionosonde stations

 图 5 重构的电离层NmF2精度统计结果 Fig. 5 Statistical accuracy of reconstructed ionospheric NmF2
3.2 电离层hmF2重构精度比较

 图 6 八个台站数据吸收前后及垂测站的电离层hmF2比较 Fig. 6 Comparison of hmF2 before and after data ingestion of eight ionosonde stations

 图 7 重构的电离层hmF2精度统计结果 Fig. 7 Statistical accuracy of reconstructed ionospheric hmF2

 图 8 低纬/高纬电离层hmF2重构误差直方图比较 Fig. 8 Histograms of reconstructed ionospheric hmF2 error at low and high latitude area
4 结论