GPS slant total electron content accuracy using the single layer model under different geomagnetic regions and ionospheric conditions
GPS slant total electron content accuracy using the single layer model under different geomagnetic regions and ionospheric conditions
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DOI：
10.1007/s00190-010-0367-5
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发表时间：
2010-05-01
影响因子：
4.4
通讯作者：
Azpilicueta, F.
中科院分区：
文献类型：
--
作者：
Brunini, C.;Azpilicueta, F.
使用全球定位系统观测对电离层研究产生了重大影响。众所周知，双频GPS观测可以提供对倾斜总电子含量（sTEC-电子密度沿射线路径的沿着线性积分）的非常精确的估计，并且精度水平受载波相位噪声和两个频率上的多路径效应的限制。尽管其精度，GPS sTEC估计可以系统地受到由与sTEC同时确定的频率间偏差（IFB）对卫星和接收器的估计中的误差的影响。因此，GPS sTEC估计的最终精度由IFB估计的误差确定。本文试图评估基于单层模型的电离层估计技术在不同电离层区域（低、中和高磁纬）、不同季节（夏至和冬至以及春分和秋分）、不同太阳活动水平（高和低）以及不同地磁条件（平静和非常扰动）的准确性。以下策略依赖于没有IFB、多径、测量噪声和任何其他误差源的合成数据集的生成。因此，当具有这样的属性的数据集被用作IFB估计算法的输入时，估计的IFB上的任何从零的偏差应当被视为由估计技术引入的误差的指示。这一评估工作的真实性是由合成数据集尽可能真实地模拟真实的电离层中可能发生的不同情况这一事实保证的。这项工作的结果表明，在高太阳活动期间，估计的sTEC的精度约为+/- 10 TECU的低地磁区和+/- 2.2 TECU的中纬度。在低太阳活动期间，可以假设精度为+/- 2 TECU的量级。对于地磁高扰期，结果表明，位于风暴影响最强地区的台站精度下降，但对于风暴影响中等地区的台站，精度与平静期相当。
The use of observations from the Global Positioning System (GPS) has significantly impacted the study of the ionosphere. As it is widely known, dual-frequency GPS observations can provide very precise estimation of the slant Total Electron Content (sTEC-the linear integral of the electron density along a ray-path) and that the precision level is bounded by the carrier-phase noise and multi-path effects on both frequencies. Despite its precision, GPS sTEC estimations can be systematically affected by errors in the estimation of the satellites and receivers by Inter-Frequency Biases (IFB) that are simultaneously determined with the sTEC. Thus, the ultimate accuracy of the GPS sTEC estimation is determined by the errors with which the IFBs are estimated. This contribution attempts to assess the accuracy of IFBs estimation techniques based on the single layer model for different ionospheric regions (low, mid and high magnetic latitude); different seasons (summer and winter solstices and spring and autumn equinoxes); different solar activity levels (high and low); and different geomagnetic conditions (quiet and very disturbed). The followed strategy relies upon the generation of a synthetic data set free of IFB, multi-path, measurement noise and of any other error source. Therefore, when a data set with such properties is used as the input of the IFB estimation algorithms, any deviation from zero on the estimated IFBs should be taken as indications of the errors introduced by the estimation technique. The truthfulness of this assessment work is warranted by the fact that the synthetic data sets resemble, as realistically as possible, the different conditions that may happen in the real ionosphere. The results of this work show that during the high solar activity period the accuracy for the estimated sTEC is approximately of +/- 10 TECu for the low geomagnetic region and of +/- 2.2 TECu for the mid-latitude. During low solar activity the accuracy can be assumed to be in the order of +/- 2 TECu. For the geomagnetic high-disturbed period, the results show that the accuracy is degraded for those stations located over the region where the storm has the strongest impact, but for those stations over regions where the storm has a moderate effect, the accuracy is comparable to that obtained in the quiet period.