Determination of dry zenith delay, DZD, is important for separating water vapor content from GPS solutions in GPS meteorology. The existing models usually cannot meet this need with high accuracy. In this study, we calibrated three popular DZD models namely Saastamoinen, Hopfield and Black models for local GPS meteorology application using radiosonde data. We test the models by comparing the predicted delays from the calibrated models against the observed delays from radiosonde data that are not included in the solution. Calibrated models on the average show 98 pc improvement over the uncalibrated model predictions over one month period. A comparison of the DZDs calculated from GPS measurements over a month period with calibrated and uncalibrated model prediction shows, on the average, 96 pc better agreement for the calibrated models.%确定大气中可降水分的含量是GPS气象学的目的之一.可降水分含量对应于GPS信号中湿分量延时.现有高精度GPS软件包只能提供天顶方向的对流层延时,但是,对流层延时由干分量和湿分量延时组成.因此,精确确定干分量延时,是分离湿分量延时墓丶?也是GPS气象学中必不可少的工作.
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