In this paper we present XtremeLoc, a low-cost indoor positioning system designed to work in situations where GPS is not a valid alternative. XtremeLoc relies on the use of portable, low-cost, Bluetooth Low Energy beacons using the iBeacon protocol. Instead of setting these beacons in fixed positions, they are carried by the persons or goods to be tracked. The beacons broadcast a signal that is received by a set of fixed, low-cost antennas. These antennas estimate the distance to the emitter using the perceived intensity of the signal, and transfer this information to a cloud-based server that calculates the position of the emitter, storing it and displaying it through a web-based interface. The use of this technology allows a precision of around two to three meters. To track elements with a higher precision, XtremeLoc allows the concurrent use of custom Ultra Wideband devices, that allow a precision of around 10 cm while using the same interface. In this paper we describe XtremeLoc architecture and main features, how to use it to find persons and goods with the help of Augmented Reality applications, and an example of use of this technology to record the behavior of individual persons during evacuation drills.
