一种改进的全球对流层天顶延迟模型

An Improved Global Zenith Tropospheric Delay Model

顾及文献[16]所建立的全球对流层天顶延迟模型GZTD的时间分辨率为24h,为进一步提高GZTD模型的时间分辨率,利用GGOS atmosphere的2002—2009年全球天顶对流层延迟格网时间序列按照其6h的时间分辨率分别建模,再采用三次样条插值计算任意时刻的天顶对流层延迟估值,由此构建了一种时间分辨率更高(6h)的改进的GZTD模型(GZTD-6h)。经过两种模型内符合检验对比分析表明,GZTD-6h模型内符合精度(bias:0.17cm,RMS:3.9cm)优于GZTD(bias:0.17cm,RMS:4.4cm)。使用全球IGS站进行外符合检验,统计结果表明GZTD-6h模型(bias:-0.22cm,RMS:4.05cm)相比GZTD(bias:-0.45cm,RMS:4.51cm)改善明显。

The time resolution of GZTD model developed by Yao[16] is 24 hours .To further improve the time resolution of GZTD model ,we used the time series of global 4D‐grid ZTD from 2002 to 2009 ,provided by GGOS atmosphere ,to construct model according to the 6 hours resolution ,and then calculated the ZTD at any time using the cubic spline interpolation method .Thus we developed an improved higher time resolution (6 h) GZTD model (GZTD‐6h) .Analyzing the inner coincidence of two models comparatively ,we found that GZTD‐6h model (bi as:0 1.7 cm ,RMS:3 9. cm) performs better than GZTD model (bi as:0 1.7 cm ,RMS:4 4. cm) .Using ZTD time series from global International GNSS Service (IGS) sites to analyze outer coincidence ,the statistical results shows that GZTD‐6h model (bi as:-0 2.2 cm ,RMS:4 0.5 cm) improves significantly ,compared with GZTD model (bi as:-0 4.5 cm ,RMS:4 5.1 cm) .