中文摘要：

对流层延迟是全球导航卫星系统（GNSS）计算的主要误差之一,其模型精度对测站坐标解算有较大影响,在高程方向尤为明显。因此,有必要对不同的对流层延迟改正模型的适用性进行评估。采用SHA解算了中国陆态网GNSS跟踪站的对流层天顶延迟数据,对常用的对流层改正模型EGNOS/UNB3m/GPT/GPT2的天顶延迟量在中国不同区域、不同季节的适用性进行了分析。结果显示,4种模型的RMS均为4~5cm,各模型RMS之差小于1cm,其中GPT2模型的RMS最小;4种模型的平均偏差（BIAS）为1cm左右,GPT2模型的BIAS最大,为1.5cm;时间上,各个模型在夏季精度普遍较低,这是因为夏季水汽丰富,对流层湿延迟变化较大;空间上,各模型在东南沿海精度较低,因为东南沿海气候湿润,湿延迟变化较大;各模型精度对测站高程不敏感,精度在比较高的测站并无明显降低。通过对不同模型在中国区域的精度分析,验证该改正模型可以为中国区域用户的对流层模型的选择提供一定的参考。

英文摘要：

As one of the main error sources in the Global Navigation Satellite System（GNSS）,the accuracy of tropospheric delay correction model influences the estimated coordinates,especially in vertical direction;therefore,it is necessary to make assessment of different tropospheric delay correction models.An assessment of four commonly used models,including EGNOS/UNB3m/GPT/GPT2,is made in this paper.The result shows that the RMS of the four models remains 4-5cm,and the difference between each model is less than 1cm,with GPT2 being the most accurate model;and the RMS of each model in summer is relatively much bigger than in winter,due to the abundant water vapor in summer,which makes it harder to model tropospheric delay precisely.All models show poor accuracy in southeast China,thanks to the rather changeable weather and the abundant water vapor there;and no model is sensitive to the height,since the accuracy varies little with respect to the variation of altitude.These findings provide a reference for the GNSS users in China area when choosing a suitable tropospheric delay correction model.