Modeling And Analysis Of Regional Tropospheric Delay

Tropospheric delay is one of main error source of improving GPS positioning precision.In the practical surveying,model method is used to eliminate the tropospheric delay,but due to the influence of meteorological representative error and meteorological element measurement error,the prediction accuracy of tropospheric delay and the accuracy of GPS surveying are not high.Differential method is common in the application, but large differences in regional meteorological parameters will bring great residual tropospheric delay and have influence on the positioning because of the complex terrain.In order to improve the prediction accuracy of tropospheric delay in small area and meet the demand of high accuracy surveying, tropospheric delay model of HongKong is established. The specific work is as follow:1. The existing tropospheric delay models are summaried and compared and give a simple description of these models.2. Analyzing the zenith tropospheric delay value of12stations in the CORS network of HongKong estimated by Bernese software,it shows that the zenith delay values of each station has an annual cycle.The regional tropospheric model based on BP neural network is established according to the gradient variation of zenith delay.Then the new model compares with the existing empirical models.3. Through the analysis of wet and dry delay of the HongKong region,it is concluded that wet and dry delay have different temporal characteristics. Then wet and dry delay spatiotemporal model are established and compare with the existing empirical models.4. To prove the validity of the model,the preprocessor of GPS data is writed by using the new model and existing positioning program.Finally,The result shows that the new model improve the accuracy about2cm.5. Some significant conclusions can be summarized from the analysis of wet and dry delay variations under special weather conditions.Figures24,Tables21,References66.