Research On Indoor Location Technology And System Based On Smart Phone

With the rapid development of Internet technology,location-based service(LBS)has become increasingly important in the information society.Especially with the rapid popularization of smart phones,LBS has been widely used in various fields such as public services,intelligent transportation,and smart medical care.Global positioning system(GPS)has met the demands of people's positioning and navigation in outdoor environment.In indoor environment,there is still no universal indoor positioning solution.Therefore,research on Key Technologies of indoor location is still a hot issue.In order to solve this problem,this paper mainly studies the indoor positioning technology of pedestrian dead reckoning(PDR),geomagnetic indoor positioning technology and corresponding systems based on smart phones.The main work of this paper is as follows:1)Focusing on the problem of accumulated error caused by long-term positioning of traditional PDR algorithm,this paper proposes an indoor positioning system and algorithm based on Bluetooth assisted PDR.The indoor positioning system is mainly composed of ground Bluetooth nodes,smart phones and positioning servers.The ground Bluetooth nodes are generally arranged at key indoor locations(such as corners,indoor entrances and exits,staircases,etc.),smartphones are installed with positioning applications,and positioning servers mainly provide indoor maps and other positioning services.In specific implementation,the positioning algorithm uses the PDR algorithm for positioning when it does not receive the ground Bluetooth node broadcast;when the user steps on the ground Bluetooth node and triggers the Bluetooth node broadcast,the positioning algorithm uses the received Bluetooth node coordinate information to determine the PDR's Initial position or correction position to eliminate the cumulative error of PDR.In addition,the step size estimation parameters of PDR positioning are updated synchronously during position correction.The experimental results show that the proposed Bluetooth assisted PDR algorithm effectively corrects the accumulated error of PDR,the location error at the correction point is 0,and the average location error is far more accurate than the traditional PDR.Under the reasonable arrangement of ground nodes(one ground Bluetooth node every 40 meters or so),the average positioning error of the system is 1.15 m.2)Focusing on the problem that the ground Bluetooth nodes cannot be arranged in some complicated indoor areas or in certain special application scenarios,this paper proposes a follow lead indoor navigation algorithm based on PDR and geomagnetic information fusion,which consists of path collection module and navigation module.During the path collection process,the PDR algorithm is used to record the leader's route information.the route is converted into multiple straight-line routes based on the detected key points(turns,ups and downs,etc.),and finally the path is passed to the follower.During the navigation process,the matching algorithm based on PDR and the geomagnetic matching algorithm dynamic time warping(DTW)is used to match the metapath of the follower with the metapath of the leader in real time to provide timely navigation prompts,key action matching and potential path deviation detection to ensure that followers can reach the same destination along the leader's path.Field experiments show that the matching rate of key actions is 100%,80%of path deviation events and path errors within the maximum physical distance of 3.9m can be detected within1.55s.The experiments results show that the system has a matching rate of 100%for key actions,and can detect 80%of path offset events within 1.55s,and detect path errors within a maximum delay physical distance of 3.9 m...