Research On Remote Sea RTK With Compass Triple-frequency Data

With the launch of BD GNSS system and the start to provide service from regional to global,the research on triple-frequency BD has becoming a focus.GNSS has wide applications on sea,but the research on BD system for far sea applications is not enough.Due to high cost on far sea work and its difficulty for repeating surveying,so higher reliability and stability on long distance and real-time kinematic navigation and positioning.And for RTK,the main problem is mainly the fixing of integer ambiguity and its validation.The main contribution of the thesis are as follows:(1)A detailed analysis is carried on for the data quality of BD system.Taking advantage of three frequencies of BD system,based on an ionosphere-free and geometry-free combination it,the noise of BD system is analyzed and compared to the other GNSS systems.In addition,the daily repeatability and spatial similarity of BD multipath are analyzed.(2)A new conditional probability method is constructed based on Bayes posterior estimation method.As current integer aperture estimation method does not take consideration of the detailed position of float ambiguity,so with the new method,when the float ambiguity is almost same far from two integer candidates,the derived conditional success rate is no less than 50%,which is more reasonable.So the new method overcomes the weaknesses of integer aperture method and more applicable to practical applications.(3)As long time is generally required for acquired full ambiguity resolution,so a partial ambiguity solution is proposed in this thesis.Contrary to current partial,the new method is in coordinate domain.Three partial solution are proposed: best,middle and average.The three partial solutions have different features,the best solution and average one has highest accuracy and middle one has higher integrity.So different users can choose different partial solutions according to their practical requirement.Based on BD observations,the three partial solutions are validated and compared with the traditional partial solution.The result shows that,compared with the traditional partial solution,the best partial solution has the higher accuracy and average one has the almost same accuracy with the traditional one.(4)Based on practical 100 km sea BD observations,the partial solutions are validated and the long-distance RTK performance on far sea with two different baselines are investigated.The result shows that the partial solutions are effective in remote sea RTK.