中文摘要：

利用中国地壳运动监测网络CMONOC中85个测站的GPS观测数据,建立3种常用的区域电离层模型：多项式函数模型（polynomial model,POLY）、低阶球谐函数模型（low-degree spheric function model,LSF）和球冠谐函数模型（spheric cap harmonic model,SCHA）,并利用数字测高仪和GPS实测数据对3个模型进行评估和比较。与数字测高仪数据的比较表明,3个模型能够较为准确地反映VTEC的变化趋势,证明了模型的有效性。与GPS实测数据的比较表明,3个模型中平均精度最高的是低阶球谐函数模型,其次是多项式模型,最后是球冠谐模型,其RMS和STD平均值依次为3.48 TECu、3.03 TECu、3.54 TECu、3.00TECu、3.82TECu、3.25TECu。利用GPS实测数据计算GIM（global ionospheric maps）模型的精度,结果显示,3个模型的BIAS均比GIM模型大,但是其RMS和STD小于GIM模型,显示了区域模型精度较高的稳定性。由各个模型与GIM模型的VTEC差值格网图可知,3个模型在建模区域的中部精度较高,多项式模型在边界有较明显的边际效应。

英文摘要：

Three commonly used ionosperic models（polynomial model（POLY）,low-degree spheric function model（LSF）and spheric cap harmonic model（SCHA））are set up by using GPS observation dataof 85 stations from the crustal movement observation network of China（CMONOC）.These models are assessed and compared using the measured data of digisondes and GPS.The models can reflect the trends of VTEC more accurately by comparing their values with the digisonde data.Comparing them with GPS measurements,it is found that the model that has the highest accuracy is LSF,the second is POLY,and the last is SCHA.Their average RMS and STD are（3.48,3.03）TECu,（3.54,3.00）TECu and（3.82,3.25）TECu respectively.The global ionospheric maps＇（GIM）precision is also calculated using the GPS data.The results show that the BIAS of the three models is greater than the GIM＇s,while their RMS and STD are a little less than the GIM＇s,which shows the higher stability of the regional models＇ precision.In addition,it can be known from the difference of VTEC grid charts between GIM and the three models that the three models have high accuracy in the middle of modeling area,while POLY has a significant marginal effect.