Using DORIS measurements for modeling the vertical total electron content of the Earth’s ionosphere
Using DORIS measurements for modeling the vertical total electron content of the Earth’s ionosphere
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DOI：
10.1007/s00190-014-0748-2
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发表时间：
2014-07
影响因子：
4.4
通讯作者：
D. Dettmering;M. Limberger;M. Schmidt
中科院分区：
文献类型：
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作者：
D. Dettmering;M. Limberger;M. Schmidt
卫星综合多普勒轨道测量和无线电定位系统（DORIS）最初是为低轨卫星的精密定轨而研制的。除此之外，它还非常适合模拟地球电离层内的电子分布。它在L波段测量两个频率，相对频率比接近5。由于地面信标的分布相当均匀，几个LEO配备了现代化的接收机，一个良好的适用性，全球垂直总电子含量（VTEC）建模可以预期。本文研究了DORIS双频相位观测数据推导VTEC的能力，以及这些数据对全球VTEC建模的贡献。DORIS预处理的执行类似于常用的全球导航卫星系统（GNSS）预处理。然而，由于DORIS数据不包含绝对信息，因此DORIS VTEC的绝对水平是从全球导航卫星系统国际服务处（IGS）提供的全球电离层图（GIM）中获取的。DORIS导出的VTEC值与IGS GIM具有良好的一致性，RMS在2和3个总电子含量单位（TECU）之间，取决于太阳活动，当仅使用仰角高于的观测值时，可以减少到小于2个TECU。DORIS VTEC与其他空间大地测量技术的数据相结合，大大提高了全球VTEC模型的准确性。如果使用DORIS VTEC数据更新IGS GIM，则可实现高达12%的改进。DORIS卫星地面航迹正下方的精度范围在1.5和3.5 TECU之间，假设高度计导出的VTEC值的精度为2.5 TECU，这些值已用于验证目的。
The Doppler orbitography and radiopositioning integrated by satellite (DORIS) system was originally developed for precise orbit determination of low Earth orbiting (LEO) satellites. Beyond that, it is highly qualified for modeling the distribution of electrons within the Earth’s ionosphere. It measures with two frequencies in L-band with a relative frequency ratio close to 5. Since the terrestrial ground beacons are distributed quite homogeneously and several LEOs are equipped with modern receivers, a good applicability for global vertical total electron content (VTEC) modeling can be expected. This paper investigates the capability of DORIS dual-frequency phase observations for deriving VTEC and the contribution of these data to global VTEC modeling. The DORIS preprocessing is performed similar to commonly used global navigation satellite systems (GNSS) preprocessing. However, the absolute DORIS VTEC level is taken from global ionospheric maps (GIM) provided by the International GNSS Service (IGS) as the DORIS data contain no absolute information. DORIS-derived VTEC values show good consistency with IGS GIMs with a RMS between 2 and 3 total electron content units (TECU) depending on solar activity which can be reduced to less than 2 TECU when using only observations with elevation angles higher than. The combination of DORIS VTEC with data from other space-geodetic measurement techniques improves the accuracy of global VTEC models significantly. If DORIS VTEC data is used to update IGS GIMs, an improvement of up to 12 % can be achieved. The accuracy directly beneath the DORIS satellites’ ground-tracks ranges between 1.5 and 3.5 TECU assuming a precision of 2.5 TECU for altimeter-derived VTEC values which have been used for validation purposes.