Research On Chinese Regional Ionospheric Delays Model And Application Based On CORS Network

Continuously Operating Reference System (CORS) network is the key point of infrastructure construction of geospatial data, so the research on CORS network structure and seamless link has high theoretical and practical significance. Using CORS network to study the variation of ionosphere becomes a research hotspot. As an important component of near-earth space environment, the delay of ionosphere is the main error source of navigation satellite system in navigation, positioning and timing. With the rapid development of navigation satellite system such as GPS and continuous improvement accuracy of positioning, high accuracy ionosphere delay model becomes the focus of study.The ionospheric delay correction of GPS satellite real-time positioning signals is usually based on ionospheric delay prediction model of navigation message, which is Klobuchar model. In the light of development of satellite navigation and its actual needs, this paper did a deep research and analysis in Klobuchar model which is used in current GPS system's navigation messages, and did an assessment of the prediction effect of Klobuchar model in China region. The main research work is summarized as follows:1. This paper briefly summarized ionosphere and the background and development outline of CORS, then explained the basic principle of GPS positioning and methods using GPS to study ionosphere and do error analysis.2. Based on the existing CORS network construction algorithms, in terms of practical applications, the CORS network construction algorithms were optimized in China regions. Using the optimized algorithm, provincial CORS networks were constructed and at the same time the seamless link and dynamic updates of CORS network were carried out, which verified the feasibility and reliability of the optimized algorithm.3. Selecting Hebei CORS station's observation data on a given day, with the help of the relationship between the Earth's magnetic field and ionosphere, GPS signals' ionospheric delay amount was calculated.4. In view of the importance of Klobuchar model in ionospheric forecast research, a study was carried out by using of this model in China's mid and low latitude regions, then the author made an assessment of the accuracy and effect of this model. A conclusion was drawn that Klobuchar model in China's mid-latitude regions forecast accuracy was higher than that in low latitude. The forecast effect in mid-latitude is about 50.2%, while in low latitude is about 30.9%. Form the data analysis, we can come to a conclusion that this model still needs further optimization and improvement to meet the demands of high precision navigation and positioning.