Regional GNSS Water Vapor Inversion Based On Precise Point Positioning

Water vapor is an important part of the atmosphere.The change of water vapor is very important for rainfall,extreme weather and other weather.GNSS water vapor detection technology is playing an increasingly important role in water vapor detection due to its advantages such as high accuracy,all-weather,high spatio-temporal resolution,and economy.This article summarizes the basic theory of GNSS water vapor inversion,studies the model that defines the average temperature of key factors in GNSS water vapor inversion;uses RTKLIB software to perform water vapor inversion based on precise single-point positioning technology;and GNSS/PWV changes during typhoon weather Study the situation.The main research contents of this article are:(1)Using the sounding station data to analyze the influencing factors of,it is found that there is a good correlation between and the meteorological elements on the ground;the temporal and spatial change trend of is analyzed,and it is found that has a significant annual periodic change trend.And the distribution of in China has obvious spatial differences.(2)The single-factor and multi-factor models of Jiangxi Province were established using the principle of least squares,and compared with the widely used Bevis model and the Jiangxi model established by Shan Jiusheng.The results show that the two localization models effectively eliminate the system errors of the other two models,and the accuracy is improved by nearly 30%.Comparing the single-factor model with the multi-factor model,we find that the multi-factor model has higher accuracy.Multi-factor models for four seasons were constructed according to seasonal divisions,and the root mean square errors increased by 1%,9%,6%,and 3%,respectively.The applicability of a multi-factor modeling method that takes into account seasonal changes is verified using two sounding stations in Tibet.In general,the multi-factor modeling method that takes into account seasonal changes is suitable for the study of high-precision models.(3)The empirical weighted average temperature model GPT3 model is researched,and it is found that the GPT3 model has a much higher computational efficiency than the currently widely used GPT2 w model.A climate zoning method was proposed to correct the calculated by the GPT3 model,making the model more suitable for China.After the correction,the model deviation was basically eliminated,and the root mean square error was improved by 0.95 K as a whole,and the improvement reached 18.7.%.(4)It is beneficial for the IGS troposphere product to compare the ZTD based on precise single-point positioning solution using RTKLIB software.The results show that the deviation is concentrated within 20 mm,and the average value of the calculated RMS is 7.33 mm.After verification,the accuracy of the ZTD calculated using the dual system of GPS+GLONASS is higher than that of the single system using GPS.The RMS is reduced by 0.58 mm,and the average reduction rate is 7.3%.Use PWV calculated from sounding station data near the station to verify the accuracy of GNSS/PWV inversion.Four average deviations(Bias),root mean square error(RMS),relative error(Epce),and correlation coefficient(R)were used.Indexes are used for evaluation.In general,the PWV obtained by the inversion is high,which can meet the requirements of GNSS water vapor inversion.(5)Using the CORS station in Hong Kong,the application of GNSS water vapor inversion in typhoon weather was explored.It is found that GNSS/PWV is closely related to precipitation.Before the rainfall,PWV has a rapid rise phenomenon.Rainfall generally occurs 1-2 hours after the peak of PWV.The change characteristics of CORS stations and PWV in Hong Kong during the typhoon transit were analyzed,and the distribution of PWV was explored,which provided ideas for further research.