Design And Implementation Of Sensor-Assisted Wi-Fi Indoor Positioning System

Under the background of the rapid development of intelligent terminals, mobile internet has been involved in all aspects of public life. More and more people like to get information and resources through their location information, which also spawned the development of positioning applications depends on GPS (Global Positioning System) or base station positioning. However, positioning based on GPS or base station has some flaws, such as in the indoor or areas of built-up, the signal of GPS or base station can be easily interfered, leading the result of positioning be untrusted. With the popularity of smart devices with wireless enabled, more and more public places have been introduced Wi-Fi to convenient and serve people. At the first beginning, Wi-Fi is not created for positioning, but with the information carried by the Wi-Fi signal, Wi-Fi can be developed to provide the function of positioning. The starting point of this paper is to collect the information of Wi-Fi, and provide indoor positioning.This paper, firstly, arranges the place of experiment, including digitize the environment of the experimental room and the layout of the AP (Access Point), so that there is a basic hardware environment to collecting data of Wi-Fi and positioning. Then after the collection of the Wi-Fi data, all the data will be validated and filtered and then inserted into the database of Android phone, to be used as the fingerprint of Wi-Fi positioning. Using the weighted KNN (K-Nearest Neighbor) algorithm, this paper implement the Wi-Fi positioning based on fingerprint database. To improve the accuracy of the positioning, this paper also introduces a way to judge the result of positioning, based on the analysis of phone holder’s walk by sensors of Android phone. Based on the regularity of the Wi-Fi RSSI (Received Signal Strength Indicator) and the distance, this paper also give a solution of the relationship between RSSI and distance. The final indoor positioning result will be given after the steps above. In the end of the paper, some potential direction is put forwarded.