Study On The Correction Of Tropospheric Delay Model Based On The Observed Data Of GNSS In Fog Haze Meteorological Condition

Fine particulate matter(PM2.5)is an important part of atmospheric pollutants,and it is a great hazard to social development and residents' health and safety.The traditional PM2.5 detection method either has a small detection range,or is expensive and complex to use,and cannot meet the growing demand for PM2.5 detection.Therefore,it is extremely urgent to explore all-weather,large-scale,and high-resolution PM2.5 detection technologies.In this paper,the characteristics of PM2.5,the correlation between PM2.5 concentration and tropospheric delay,and the PM2.5 diffusion model are studied in depth,and the research on PM2.5 detection in urban areas has been carried out.Specific studies include the following aspects:1.The distribution characteristics and vertical distribution characteristics of PM2.5 are studied,and the electromagnetic properties of PM2.5 medium are deduced.The effect of PM2.5 on electromagnetic waves is analyzed from the scattering and absorption effects,and an electromagnetic wave propagation attenuation model of PM2.5 medium is further established.So far,the impact of PM2.5 on GNSS signals has been theoretically explained.Taking the four IGS stations with different PM2.5 pollution levels at the same time as an example,the accuracy of the three classic tropospheric delay models is compared and analyzed,and it is concluded that the Black model has the best accuracy.2.The problem of refractive index in tropospheric delay is further analyzed.Analyze the correlation between refractive index and meteorological parameters in Beijing,Shenyang,and Chengdu during the PM2.5 pollution period.Then,a refractive index profile inversion model is established based on the statistical inversion method and the accuracy of the model is verified.The period of PM2.5 pollution in Jiuquan is selected as For example,a refractive index profile inversion model is established based on a related support vector machine and the model accuracy was verified.3.The IGS format file and PM2.5 monitoring station data published by the base stations of the CMONOC ware selected to analyze the correlation between PM2.5 concebtration and tropospheric delays in the Beijing-Tianjin-Hebei region,Southwest China,Lanzhou and Shenyang regions from 2014 to 2017.And study the relationship between PM2.5 heavy pollution period,establish a regression analysis model and verify the accuracy of the model.4.Based on the PM2.5 Gaussian diffusion model,an improved PM2.5 diffusion model suitable for Chinese cities is proposed.The influence of different factors in the model is simulated and analyzed.Taking Tiantan Park in Beijing as an example,the accuracy of the model under different atmospheric conditions is analyzed through experiments.Combined with the correlation between PM2.5 and tropospheric delay,a new PM2.5-assisted detection technology is proposed.Finally,four Beijing reference stations are selected as examples to verify the accuracy of the detection technology.