Research On Correction Model Of Tropospheric Propagation Medium Of Measurement And Control Station

Electromagnetic waves of TI’&C radar in troposphere will be influenced by environmental factors, which leads large error in measuring tracking. According to refraction waves in the troposphere of specific control stations, this research makes full use of the measurement and control data, meteorological data as basic data to carry out the study of tropospheric refraction correction model.First we analyze the relationship between meteorological data and the refractive index profile of the troposphere model, then we establish the quarterly tropospheric refractive index profile model of control stations, finally we put forward three empirical correction model and achieve some results in practical engineering.(1)The first chapter analyzes three weather elements which influence the electromagnetic wave in the troposphere, and introduces and compares then vapor pressure model which makes significant influence on the electromagnetic wave refraction emphatically. Besides, the Buck 1981 vapor pressure model is adopted in order to improve the refractive index prediction accuracy. Moreover, the data sources of the control stations’ site and data processing method are introduced, and the original refractive index data and the change of refractive index for the whole year are achieved which provide basic data for building the refractive index profile in the next chapter.(2)The second chapter takes the Hopfield Refractive Index Model as the prediction method based on the comparison and analysis of commonly used refractive index models in the troposphere. The refractive index profile data of each control station is established across the country according to eight sites’ high altitude weather data. The sites include Kashgar, Jiuquan, Beijing, Xi’an, Chengdu, Guangzhou, Guilin, and Sanya. Based on the contrastive analysis of dry and wet refractive index, the nationwide trend of refractive index is achieved, which provides basic refractive index data for the study of refraction correction model in the next chapter.(3)The third chapter studies three commonly used refraction correction methods and introduces some other refraction correction methods Based on the analysis of the Hopfield Correction Model and Ray-tracing method in different elevation, the achieved result shows that the Hopfield Correction Model is only applicable to the target elevation in more than 30 degrees and the Ray-tracing method is well used for high accuracy measurement system.(4)In the final chapter, according to the contrastive analysis of large number of historical refraction correction data, three refraction correction models are established by statistical method combined with experience. The resultshows that the proposed empirical model can not only meet the correction precision requirement of Ray-tracing method, but also be applied to practical engineering.