InLoc: An end-to-end robust indoor localization and routing solution using mobile phones and BLE beacons

This paper discusses `InLoc', an accurate and a robust positioning and tracking system using commercial mobile devices, with an integrated feature of route finding for the user from a source to the desired destination. The system exploits easily available building floor maps in raster form, with an easy conversion to vector model, eliminating the need of specially designed vector maps, thereby making the system scalable for large indoor maps and more implementation friendly. This also enables the vector map to be used in both Particle Filter based IMU tracking, and routing. Additionally, an efficient method for independent fusion of location information from phone IMU sensors and Bluetooth Low Energy (BLE) beacons is demonstrated. The method caters both dynamic and static properties of the system state. Furthermore, the paper proposes a novel approach for estimating the distance from BLE beacons using RSSI (Received Signal Strength Indication) measurement. InLoc can be readily used for any size of building floors for applications like tracking, routing and guiding system, emergency evacuation, meeting planners etc. requiring no separate effort to rebuild the vector map from scratch. The system yields a mean tracking error of less than 0.4m in location, and yields 0.9m as an average positioning error using fusion.