Study On The Regional Tropospheric Delay 4-Dimension Modeling And Applications Based On The Multiple Reference Stations Networks

Tropospheric delay is one of the main errors of GPS surveying and navigation. High accuracy regional tropospheric delay modeling and fitting are studied in the dissertation to meet the needs of research on geodesy, earth science and meteorology. The basic characters of troposphere, theory and method of tropospheric delay resolving, as well as GPS meteorological applications etc. are included. Some comprehensive and intensive research works on tropospheric delay in GPS positioning applications are conducted to provide a helpful groundwork for future research.There are mainly three parts in the dissertation:Firstly the background is introduced, including the significance of troposphere delay research, the propagation influence of electromagnetic wave in the troposphere and the basic method of tropospheric delay estimation.Secondly the dissertation focuses on the method and theory of tropospheric delay modeling in GPS positioning, which are presented as the following:1. Proposed a layered atmospheric refraction model based on the character of atmospheric refraction varated with altitude. Then a new the tropospheric delay model with integral formula is obtained. Some tests are held to make the comparison of the new model with the traditional ones, e.g. Saastamoinen and Hopfield. The results showed that the accuracy of proposed tropospheric delay model is the comparable with or better than the two traditional models.2. Developed a new mapping function, namely HT mapping function using geometric method,. It is independent of any meteorological data, the accuracy of the new mapping function is comparable with NMF (Niell Mapping Function) model, but the computing velocity of HT is about four times faster than NMF.3. A regional tropospheric delay model is developed by analyzing the relationship between three-dimensional coordinates and tropospheric delay of the reference stations. Tropospheric delay can be estimated in real time with the accuracy of 1 centimeter using this model.4. Some useful methods are developed to eliminate the effects of tropospheric gradient by analyzing the changes of atmosphere.5. IGS ultra rapid products can meet the needs of tropospheric delay real time monitoring applications by the proposed method.Finally GPS meteorological applications are discussed. Both GPS positioning and GPS meteorology are benefited from troposphere delay modeling. Atmospheric mean temperature model is established using the data of several...