附有国际参考电离层约束的全球电离层模型

Global Ionospheric Model with International Reference Ionosphere Constraint

提出利用国际参考电离层附加虚拟观测值对总电子含量值为负数的地区、赤道异常区域和南半球区域电离层进行约束,在日固地磁参考系下采用15阶次的球谐展开建立全球电离层模型,解算得单位权中误差约为1.6TECU,残差绝对值小于3TECU的比例达90%以上,且全球电离层图与IGS电离层工作组的电离层产品精度相当,偏差RMS约为3.7TECU,卫星差分码偏差与欧洲定轨中心相比优于0.1ns,与IGS相比优于0.2ns,接收机差分码偏差与欧洲定轨中心相比优于1ns(大部分优于0.5ns),与IGS相比优于1.5ns。实验结果表明,附有国际参考电离层约束的全球电离层模型确保了全球各个地区的电离层总电子含量为正值,且有效提高了全球电离层模型在赤道异常区域、海洋地区和南半球的精度。

An optimized method for global ionospheric modeling with an international reference ionosphere constraint is proposed. It constrains the total electron content of the ionosphere over the equatorial anomaly area, southern hemisphere and the area where the value of the total electron content is negative. The vertical total electron content was modeled in a solar-geomagnetic reference frame using a spherical harmonics expansion up to degree and order 15. The standard deviation of unit weight derived from processing was about 1.6 TECU. The proportion of absolute residual errors was less than 3 TECU achieves above 90%. Global ionosphere maps have a good agreement with IGS, and the RMS of difference is around 3.7 TECU. The difference of the satellite＇s differential code bias is just about 0.1 ns when compared with CODE, and 0.2 ns compared with IGS. The difference of receivers differential code bias is about Ins （mostly 0.5 ns） when compared with CODE, and 1.5 ns when compared with IGS. The results indicate that the global ionosphere model with international reference ionosphere constraint ensures that the values of total electron content all over the globe are positive, and enhances total electron content precision of ionosphere over the equatorial anomaly area, ocean and southern hemisphere.