Research On BDS/GPS Dual-mode Positioning Satellite Selection And Solution Algorithm

With the rapid development of science and technology and the continuous improvement of navigation technology,navigation technology is increasingly inseparable from people's lives and related scientific research.With the continuous upgrade of the global navigation satellite system,its application fields are also constantly expanding.From sea,land and air positioning to monitoring of agricultural production,from management of fisheries and forestry to disaster prevention and reduction,navigation technology has played an important role.The improvement of navigation technology has expanded the space for the development of information science.Nowadays,having advanced navigation technology has become an important indicator of the scientific and technological progress of a country and a nation.In recent years,with the rapid development of navigation systems in various countries,aiming at the different characteristics of Beidou navigation satellite system(BDS)and global positioning system(GPS),the information fusion of the two systems can not only complement each other in function,but also improve the stability and accuracy of the system.Therefore,this paper focuses on the research of satellite selection and solution in BDS / GPS integrated navigation system.Based on the research results of existing multi-mode positioning and navigation technology,the positioning accuracy of BDS / GPS integrated navigation system is improved by improving the satellite selection algorithm and solution algorithm.The main contents and innovations of this paper are as follows:(1)Using a multi-mode satellite navigation system for positioning can obtain a larger number of visible satellites than single-system navigation and positioning,which is beneficial to improve positioning performance,but the calculation amount of the navigation system also increases exponentially,selecting satellites for traditional traversal the algorithm is not applicable to this problem in multi-mode satellite navigation systems.In this paper,a BDS/GPS dual-mode composite strategy adaptive fast satellite selection algorithm is proposed.The algorithm selects satellites based on the composite strategy of geometric accuracy factor and carrier signal-to-noise ratio.The height angle filtering angle is adaptively adjusted according to the number of visible satellites to quickly obtain the distribution of sub-optimal constellations,and the constellation is measured by the geometric accuracy factor.Finally,the proposed algorithm is compared with the traditional fast satellite selection algorithm,and MATLAB is used for simulation analysis.It is found that the proposed algorithm has a relatively small loss in accuracy compared to the optimal constellation,and the calculation time is about the traditional optimal one thousandth of the constellation satellite selection method verifies the effectiveness of the algorithm in the dual-mode satellite navigation system.(2)In view of the influence of multipath effect,ionosphere delay,troposphere delay and other factors in positioning,the introduction of Kalman filter and its extended algorithm in positioning solution can reduce the risk of filter divergence,reduce the error of pseudo range observation,and improve the stability of positioning.Among them,the cubature Kalman filter depends on the initial settings,and cannot adjust its own parameters according to environmental changes,as well as the abnormal errors in the observation of the satellite signal capture link,which may produce a large state estimation when performing the cubature Kalman filter.In view of the above problems,this paper proposes to combine robust algorithm and adaptive algorithm with cubature Kalman filter to adjust robustly to the measurement noise.Through simulation analysis,it can be concluded that this method can effectively improve the system positioning accuracy.