Abstract In this paper, GNSS ionospheric observations from ground-based and spaceborne systems were simulated, and the global 3D ionospheric density field was reconstructed by Kalman-Filter algorithm. Various errors and influences in the assimilation of the ionospheric data were analyzed, and corresponding improvement methods were proposed, which were verified from the following two aspects based on simulation analysis: 1. From the statistics of slant total electron content(TEC): (a) the influence of the shell with altitude between 800 km and 20000 km was 2030%, and could be reduced by the two-step assimilation method; (b) the influence of ionospheric time variations could reach 10%, and was reduced to 5% by the correction proposed in this paper; (c) the influence of the ionospheric grid representation was 2.5%, and was reduced to 0.9% by the method of the bilinear interpolation at intercept midpoint. The three errors mentioned above are called assumptions’ error, for they always be ignored or deduced by theoretical assumptions. 2. The results of electron density reconstruction showed algorithm with assumptions errors corrections was better than origin one, which confirmed the effectiveness of the correction algorithms to the assumptions errors. And it was also showed that the Kalman filter assimilation algorithm was better than the Abel-Retrieved method, especially in ionospheric F2 region, for there is no ionospheric symmetric assumption.

中文翻译：

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地基/星载电离层观测同化假设误差来源分析

摘要 本文模拟了地基和星载系统的GNSS电离层观测，利用卡尔曼滤波算法重建了全球3D电离层密度场。分析了电离层数据同化过程中的各种误差和影响，提出了相应的改进方法，并在模拟分析的基础上从以下两个方面进行了验证： 1. 从斜向总电子含量（TEC）统计： )海拔在800公里至20000公里之间的炮弹的影响为2030%，可通过两步同化法降低；(b) 电离层时间变化的影响可达10%，通过本文提出的修正降低到5%；(c) 电离层网格表示的影响为 2.5%，并降为 0。9% 截距中点双线性插值法。上面提到的三个错误称为假设错误，因为它们总是被理论假设忽略或推导出来。2、电子密度重建结果表明，假设误差修正算法优于原算法，验证了假设误差修正算法的有效性。并且还表明卡尔曼滤波器同化算法优于Abel-Retrieved方法，特别是在电离层F2区域，因为没有电离层对称假设。电子密度重建结果表明，假设误差修正算法优于原算法，证实了修正算法对假设误差修正的有效性。并且还表明卡尔曼滤波器同化算法优于Abel-Retrieved方法，特别是在电离层F2区域，因为没有电离层对称假设。电子密度重建结果表明，假设误差修正算法优于原算法，证实了修正算法对假设误差修正的有效性。并且还表明卡尔曼滤波器同化算法优于Abel-Retrieved方法，特别是在电离层F2区域，因为没有电离层对称假设。