The Research Of Indoor Positioning Technology Based On WiFi And Sensors

With the rapid development of wireless information technology,people's requirements of location based service(LBS)gradually increase.In the outdoor environment,the global positioning system(GPS)can provide accurate location.based services and apply in various fields.However,for the indoor environment,because of the building itself barrier and internal structure such as doors,windows,walls,GPS signal receiving device receives in the indoor environment is very weak,the positioning accuracy is greatly decreased,it is difficult to meet the requirements of precise indoor localization.At present,indoor wireless positioning mainly use Wi Fi,sensor,infrared,ultrasonic,PFID positioning technology.Especially,positioning technology based on Wi Fi due to the wide depl oyment and the low cost,become the ideal solution for indoor positioning system.In this paper,in order to realize the indoor positioning system based on Android,we use not only the fingerprint matching technology based on Wi Fi,but also the multiple sensors of the mobile devices and map matching technology based on routing table to assist the indoor positioning.Test shows that by applying the proposed algorithm,positioning precision is increased.Firstly,this paper introduces some location method b ased on Wi Fi,summarizes the basic theory and analyzes advantages and disadvantages of the positioning method.Positioning method based on fingerprint matching without the need for improvement of the existing network.Therefore,positioning method based on Wi Fi is an ideal indoor positioning method.This paper uses a positioning method based on fingerprint matching of the average of the wireless signal strength repeated collected as position feature.Secondly,this paper uses not only the fingerprint matchi ng technology based on Wi Fi,but also the multiple sensors of the mobile devices and map matching technology based on routing table to make up for the inadequacy of positioning method based on Wi Fi.Combined with these technical advantages,this method improves the positioning accuracy.Finally,this paper implements an indoor positioning system based on Android.The positioning system is composed of mobile terminals and a positioning server.Mobile terminals collect periodically the strength of the signal of all APs surrounded by them and sensor data,and sent to the positioning server.The positioning server stores positioning fingerprint information,and executive positioning algorithm,locate mobile terminals,returned the result to mobile terminals and display.The experiment results show that the algorithm has high speed and positioning error is about 3.65 meters,so it is very ideal positioning system in indoor environment.