Research And Implementation Of Indoor Positioning Based On The Android Mobile Phone

The indoor positioning means obtaining the position information of a person or an object in a room. Due to the popularity of the GPS, the outdoor localization technology is fully developed. But in the indoor condition, the GPS signal is too weak to be detected, so indoor positioning needs new technologies. At present, RFID, Bluetooth, Infrared, UWB, ZigBee, WiFi and PDR (Pedestrian Dead Reckoning) and many other techniques have been used in this area. PDR is a technology using sensor information to calculate the relative position. Firstly, it detects the steps and estimates the step length of a pedestrian using the accelerometer. Then it utilizes the gyroscope and the electronic compass to calculate the azimuth. Finally it obtains the relative position of the pedestrian. Compared with other indoor positioning techniques, PDR has higher positioning accuracy and it won’t be affected by the environment. However, it can only obtain the relative position information and has cumulative errors; While WIFI positioning is based on the receiving signal strength from the AP (Access Point), so it can give the absolute position information and help reduce the PDR positioning cumulative error, but the positioning accuracy depends on the environment. Therefore, this article proposes a fusion strategy of PDR and WIFI positioning technologies to achieve high accuracy and stability indoor localization. In addition, as APs widely exist in the room, it is easy to realize PDR and WIFI positioning without adding additional hardware equipments.As the smart phones become more and more popular, and they were embedded with WiFi module, accelerometer, electronic compass and gyroscope, the research and implementation of indoor positioning based on the android mobile phone has become a hotspot. This paper chooses XIAOMI M1as hardware platform to implement the indoor positioning system. Firstly, this paper describes how to achieve indoor positioning system based on WiFi. Then, it describes indoor positioning system based on PDR, and puts forward a new step length estimation algorithm to improve the positioning accuracy. Finally, this paper puts forward a fusion strategy for indoor positioning based on PDR and WiFi technologies.The main contents and results of the research in this paper are as follows:(1) Researching and designing the indoor positioning system based on WiFi, and setting up the WiFi indoor positioning server. (2) Researching and designing the indoor positioning system based on PDR.(3) Putting forward a new step length estimation algorithm to improve the positioning accuracy.(4) Putting forward a fusion strategy for indoor positioning based on PDR and WiFi.