Spatiotemporal accuracy evaluation anderrors analysis ofglobal VTEC maps using asimulation technique
Spatiotemporal accuracy evaluation anderrors analysis ofglobal VTEC maps using asimulation technique
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基于仿真技术的全球VTEC地图时空精度评估与误差分析
DOI：
10.1007/s10291-022-01343-y
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发表时间：
2022
期刊：
影响因子：
4.9
通讯作者：
李新星
中科院分区：
文献类型：
--
作者：
林剑;李新星
垂直总电子含量图（VTEC）的计算逐渐成为国际上关注的重要问题。GNSS服务。鉴于目前的文献报道，很少有研究涉及到的每个误差的定量分析。VTEC地图及全球VTEC精度的时空特征。基于单层模型和球面。本文提出了一种利用模拟GPS数据全面验证VTEC .map精度的方法。分析和讨论了全局VTEC精度的时空特征，以及载波相位对码调平、映射函数（MF）、DCB估计和系数滤波等不同处理步骤引起的误差。在细节。此外，还讨论了太阳活动对全球VTEC地图精度、MF和DCB估算的影响。结果表明：①日出时的中频误差比日落时的中频误差更显著；通过理论分析、电离层掩星和VTEC测量，证明了其重要特性；其次，在密集和均匀的区域，MF是VTEC处理中最重要的误差源。分布式GPS站，例如北美和欧洲。这些区域的VTEC精度可提高100%。随着卫星仰角从12°增加到30°；最后，与使用的全局VTEC精度进行了比较。在350个GPS站观测数据的基础上，双GPS站分布均匀，精度提高了306%。
The computation of vertical total electron content (VTEC) maps has become an important issue gradually for the international .GNSS service. Given the current literature reports, little research is involved in the quantitative analysis of each error of .the VTEC map and the spatiotemporal characteristic of global VTEC accuracy. Based on the single layer model and sphere .harmonic function, we propose an approach using simulated GPS data to comprehensively verify the accuracy of the VTEC .map. The spatiotemporal characteristic of global VTEC accuracy and the errors induced by diferent processing steps, i.e., .carrier phase to code leveling, mapping function (MF), DCB estimation and coefcient ftting, are analyzed and discussed .in detail. In addition, the efect of solar activity on the accuracy of the global VTEC map, MF and DCB estimation has been .discussed. The results suggest: First, it is found that the MF error at sunrise is more signifcant than that at sunset, and this .important characteristic can be proven based on the analysis of theoryand ionospheric radio occultation and VTEC measurements;. second, the MF is the most signifcant error source in the VTEC processing for regions with dense and homogeneous .distributed GPS stations, e.g., North America and Europe. The VTEC accuracy in these regions can be improved by 100% .with the satellite elevation cutof angle increasing from 12° to 30°; fnally, compared with the global VTEC accuracy using .350 GPS stations observations, the accuracy is improved by 306% based on the double GPS stations with even distribution.