GPT2/GPT2w+Saastamoinen模型ZTD估计的亚洲地区精度分析

The determination of GNSS zenith tropospheric delay by GPT2/GPT2w+Saastamoinen model and its performance analysis in Asia

针对Global Pressure and Temperature2/Global Pressure and Temperature 2w(GPT2/2w)模型在亚洲区域对流层延迟估计中的适用性问题,该文基于GPT2/2w模型,结合Saastamoinen模型(分别用GPT2S、GPT2w-1S、GPT2w-5S表示)估计亚洲地区2007—2017年10年的天顶对流层延迟(ZTD)并分析其精度与时空分布。使用欧洲定轨中心(CODE)的ZTD产品来验证模型在亚洲地区的精度。分析结果表明GPT2w-1S模型精度最高,偏差(Bias)为0.88 cm,均方根误差(RMSE)为4.63 cm,GPT2w-5S模型精度次之,GPT2S模型最差。受水汽分布影响,时间上,3种模型精度表现出季节特性,冬季精度最好,夏季精度最差;空间上,3种模型在高海拔地区精度较好,模型精度对纬度的依赖性不明显且纬度对3种模型的影响程度差别不大。

To solve the applicability problem of the Global Pressure and Temperature 2/Global Pressure and Temperature 2 w(GPT2/2 w)model in Asia.The zenith tropospheric delay(ZTD)in Asia for a period of 10 years(2007-2017)was investigated through incorporating the GPT2/2 w model with Saastamoinen model(represented by GPT2 S,GPT2 w-1 S,and GPT2 w-5 S respectively).The performance of the integrated model was then assessed in terms of accuracy and spatiotemporal distribution.The Center for Orbit Determination in Europe(CODE)ZTD products were used for the validation of the new model.The results showed that the GPT2 w-1 S model could provide tropospheric delay corrections with a bias of 0.88 cm and a root mean square error(RMSE)of 4.63 cm respectively,the performance of which is the best,followed by the GPT2 w-5 S model,the performance of the GPT2 S model was the worst.Influenced by water vapor distribution,the performance of the three models tested showed seasonal characteristics,with the best in winter and the worst in summer.No latitude-dependent feature was found among the three models and their performance in general tended to be better in high altitude regions.However,the tendency and level of impact due to latitude variations was found to be similar for all the three models.