Research And Implementation Of An Indoor Navigation System Based On Intelligent Terminal

With the rapid development of the global satellite navigation and positioning technology,the outdoor navigation system is widely used in the fields of transportation,national defense security and so on.But the indoor environment is difficult to obtain more accurate satellite navigation data because of the building interference and other factors.With the increase of human activities in the indoor environment,various indoor navigation technology appears and developed rapidly,human life is increasingly dependent on indoor navigation technology,but there are many shortcomings in different indoor navigation technologies..In order to improve navigation accuracy,reduce system cost,facilitate mobile pedestrian navigation,considering indoor environmental characteristics,a navigation and positioning system based on Pedestrian Dead Reckoning(PDR),WIFI and landmarks fusion is applied to satisfy the navigation and location requirements of pedestrians in complex indoor environment.In order to make full use of the complementary advantages of PDR,WIFI and landmarks,a fusion algorithm based on extended Kalman filter(EKF)is proposed in this paper.For the WIFI positioning system,in the real-time positioning stage,the WIFI location is obtained by fuzzy reasoning weighted location fingerprint algorithm.The trusted area is defined by the location data and the WIFI anomaly detection of pedestrians before,so it can reduce the computation cost and improve the positioning accuracy of WIFI.The indoor environment location point is marked by landmarks which characteristics is more clear,and the off-line fingerprint database is formed together with the WIFI system in the phase of real-time positioning prediction.The PDR positioning system analyzes the user attitude model,calculates the pedestrian gait and steps,and uses the gyroscope and acceleration sensors to determine the user heading based on the EKF heading model.In order to reduce the accumulative error of PDR and achieve continuous indoor navigation and location,the navigation algorithm based on EKF fusion is implemented based on PDR system data as state variables,WIFI and landmarks as measure variables,and mobile client which is built on Android platform is built in the indoor navigation system for mobile terminals.After the test of the actual indoor environment data acquisition and mobile terminal navigation system,from the experimental data are analyzed,we can conclude that: the indoor positioning system PDR,WIFI and landmarks fusion compared to PDR and WIFI fusion system,PDR and landmarks system fusion system,the positioning accuracy is improved,and the precision of fusion was decided to based on the positioning error can be guaranteed about 1m,which is fitted the needs of pedestrian indoor navigation based on personal daily.