A new global zenith tropospheric delay model IGGtrop for GNSS applications
A new global zenith tropospheric delay model IGGtrop for GNSS applications
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用于 GNSS 应用的新全球天顶对流层延迟模型 IGGtrop
DOI：
10.1007/s11434-012-5010-9
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发表时间：
2012-06-01
影响因子：
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通讯作者：
Li ZiShen
中科院分区：
文献类型：
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作者：
Li Wei;Yuan YunBin;Li ZiShen
对流层延迟是全球导航卫星系统测量误差的主要来源之一。它通常通过使用经验校正模型来补偿。本文利用全球国际GNSS服务站的对流层延迟（ZTD）时间序列和全球国家环境预报中心再分析数据的年ZTD，进一步分析了全球ZTD的时空变化。根据ZTD的特点，提出了一种新的ZTD校正模型IGGtrop。实验结果表明，这种新的三维网格为基础的模型，适应纵向以及纬向变化的ZTD性能优于仅基于纬度的模型（如UNB 3，EGNOS，和UNB 3 m）。IGGtrop的全局平均偏差和RMS分别约为-0.8 cm和4.0 cm。UNB 3、EGNOS和UNB 3 m的偏倚值分别为2.0、2.0和0.7 cm，RMS值分别为5.4、5.4和5.0 cm。IGGtrop对不同区域的预测误差比EGNOS和UNB 3 m一致得多。在中国，IGGtrop的性能（偏差值为-2.0至0.4 cm，RMS为2.1至6.4 cm）明显优于EGNOS和UNB 3 m的性能（上级）。它也表明，IGGtrop偏差随高度变化不大，其RMS值往往随着高度的增加而减小。此外，在南半球，IGGtrop通常比EGNOS和UNB 3 m更准确地估计ZTD。
Tropospheric delay is one of the main sources of measurement error in global navigation satellite systems. It is usually compensated by using an empirical correction model. In this paper, temporal and spatial variations of the global zenith tropospheric delay (ZTD) are further analyzed by ZTD time series from global International GNSS Service stations and annual ZTDs derived from global National Centers for Environmental Prediction reanalysis data, respectively. A new ZTD correction model, named IGGtrop, is developed based on the characteristics of ZTD. Experimental results show that this new 3D-grid-based model that accommodates longitudinal as well as latitudinal variations of ZTD performs better than latitude-only based models (such as UNB3, EGNOS, and UNB3m). The global average bias and RMS for IGGtrop are about −0.8 cm and 4.0 cm, respectively. Bias values for UNB3, EGNOS, and UNB3m are 2.0, 2.0, and 0.7 cm, respectively, and respective RMS values 5.4, 5.4, and 5.0 cm. IGGtrop shows much more consistent prediction errors for different areas than EGNOS and UNB3m. In China, the performance of IGGtrop (bias values from −2.0 to 0.4 cm and RMS from 2.1 to 6.4 cm) is clearly superior to those of EGNOS and UNB3m. It is also demonstrated that IGGtrop biases vary little with height, and its RMS values tend to decrease with increasing height. In addition, IGGtrop generally estimates ZTD with greater accuracy than EGNOS and UNB3m in the Southern Hemisphere.