The Correlation Research Between Precipitable Water Vapor and Zenith Tropospheric Delay

There is a strong relevance between precipitable water vapor (PWV) and zenith tropospheric delay (ZTD). In this paper, using GPS data of Great Wall Station and meteorological data on ground, we calculated the PWV of empirical model directly by using ZTD and the results of calculation using the measured data had been verified. It had been proved that the precision of this empirical model can reach 2.5 mm. In addition, the accuracy of PWV in the traditional model is affected by atmospheric pressure seriously. However, we used atmospheric pressure and zenith tropospheric delay as two variables to calculate precipitable water vapor, and the precision of the model could reach to 1 mm.