Pseudorange Integrated Positioning And Optimization Methods Study Of BDS/GPS

GNSS includes GPS,Galileo,GLONASS,BDS. By the end of 2012, BDS have achieved the public service of the Asia-Pacific region, marking the initial completion of China's own satellite navigation system. In recent years, GNSS is playing an increasingly important role in transportation, mapping, communication, navigation, defense and so on. However, GNSS is also facing a lot of problems: first, in the case of some of the building complex terrain buildings of the city, mountains, valleys and other stands, the positioning accuracy is relatively low, in particular, the current number of BD satellites is only 16, in the case of the south of the satellite blocked, pseudorange positioning accuracy of BDS is not satisfactory, or even unable to locate; second, due to the influence of the atmosphere, multipath, when satellite data quality that the receiver receives is not high, BDS and GPS pseudorange positioning effect is not very good. For this case, the positioning of multi-system and pseudorange positioning optimization technology can effectively solve this problem.Relying on 863 projects, the paper major researchs integrated positioning of BDS/GPS pseudorange and optimization methods of improving the integrated positioning accuracy.(1)The paper simply introduces structures of satellite navigation system, analyzes advantages of BDS and GPS, focuses on studying error Sources on positioning process, analyzes and applies related error correction model;(2)On the basis of full understanding and analysis of principle, the paper analyzes BDS/GPS pseudorange positioning and programs to achieve it. Simply introduces the concept of pseudorange measurements, deduces positioning process by pseudorange equation. On this basis, gives the single system positioning process, uses the collected real satellite data to achieve BDS/GPS single system positioning. On the basis of the single system positioning, focus on the analysis of the basis to achieve integrated positioning and mathematical models, gives integrated positioning process, achieves BDS/GPS integrated positioning, contrasts and analyzes the positioning results to draw conclusions, and put it as the basis for later study;(3)To undertake the above, when the positioning accuracy of single system itself is not high, the paper research optimization methods to improve the integrated positioning accuracy. On the one hand in terms of algorithms, improves the positioning accuracy by applying the weighted least squares method and Kalman filter algorithm, and analyzes the three algorithms. On the other hand from the process of positioning itself, aiming at some problems, optimizes and improves the calculation process of satellite transmission time, to make it more accurate and reasonable.By programming the results show the realization, BDS/GPS integrated positioning can greatly increase the number of visible satellites, improve satellites constellation structure, optimize the positioning accuracy, especially for the BDS positioning, the integrated positioning makes up for the defects of insufficient of BDS satellites number, significantly improves the positioning accuracy; In addition, by applying the weighted least squares method and Kalman filter algorithm, improves the utilization efficiency of satellite data, enhances the stability and reliability of positioning results; For the optimization and improvement of the positioning in this paper, the positioning accuracy has been improved by the positioning results and there is a certain optimization effect.