Research On Seamless Indoor And Outdoor Integrated Positioning Method Based On Satellite/IMU/WiFi

With the development of science and technology,people pay more and more attention to the accuracy of their own position information.As a single positioning technology has its own advantages and disadvantages,how to combine these positioning technologies to achieve seamless positioning in different environments has become one of the research hotspots in the field of navigation.Satellite navigation and inertial navigation are two widely used navigation technologies,and with the popularity of Wi Fi network,indoor positioning technology based on Wi Fi network is gradually mature.In order to improve the accuracy and applicability of the positioning method,this paper studies the indoor and outdoor seamless integrated positioning method based on satellite /IMU/Wi Fi.Firstly,a integrated positioning algorithm experimental system based on satellite /IMU / Wi Fi is built,including mobile data acquisition part,PC algorithm implementation part and Wi Fi network access equipment,and the indoor experimental environment is deployed.Secondly,the weighted K-nearest neighbor method(WKNN)is improved.Mahalanobis distance is used as the distance measurement method in WKNN,and the signal stability of the access point is used as the weight parameter for calculating the distance between the moving target and the reference point.K reference point positions close to the moving target are weighted to obtain the moving target position.At the same time,in order to improve the speed and accuracy of positioning,K-means clustering is used for Wi Fi fingerprint database,and the Wi Fi fingerprint positioning results are filtered.Thirdly,a satellite/IMU/Wi Fi integrated positioning scheme is designed,the state space model of the combined positioning system is derived,and a method of indoor and outdoor position coordinate conversion based on a four-parameter model is proposed.In order to achieve indoor and outdoor seamless positioning,the positioning environment is divided into indoor area,outdoor area and indoor and outdoor junction area.Wi Fi / IMU integrated positioning is used in indoor area,satellite / IMU integrated positioning is used in outdoor area,and IMU positioning is used in indoor and outdoor junction area.According to the number of satellites and the quality of AP signal,the moving target area is judged.Fourthly,based on the cubature quadrature Kalman filtering(CQKF),an adaptive CQKF based on Variable Center maximum entropy(VCMCCQKF)is proposed.The algorithm is used to filter the Wi Fi positioning results and fuse the satellite / IMU / Wi Fi data to estimate the positioning results.The algorithm uses the variable center maximum entropy criterion to estimate the measurement noise and reduce the influence of non gaussian and non-zero mean noise on state estimation.In order to test the performance of the integrated localization algorithm,the filtering algorithm contrast experiment and indoor and outdoor localization experiment are carried out.The experimental results show that VCMCCQKF has higher positioning accuracy than MCCQKF and CQKF,and the designed indoor and outdoor switching method can effectively and stably switch indoor and outdoor positioning methods.The research results of this paper provide reference ideas for indoor and outdoor seamless integrated positioning,and lay the foundation for further research on indoor and outdoor seamless integrated navigation system.