Distance estimation to BLE beacons using Raspberry Pi 3 boards for indoor positioning and social tracking applications

The Raspberry Pi (RPi) boards family is not only a set of versatile devices suitable for quick prototyping, but robust, low-cost systems that can be used in production. For example, RPi 3B and RPi 3B+ models have integrated WiFi/Bluetooth interfaces , so they can be used to interact with Bluetooth Low Energy (BLE) beacons. In particular, distance among beacons and Raspberries can be inferred using the received signal strength indicator of Bluetooth signals. This feature allows to build low-cost indoor positioning systems, that in turn can be used to track people that works closely for disease prevention. In this paper we present the results of an empirical study that aims to determine whether RPi 3B and RPi 3B+ models are equally good to be used as receiving stations, and whether their relative orien-tations with respect to BLE beacons make any difference. Among other findings, in this work we show that the Bluetooth/WiFi antenna design of the RPi 3B+ receives different RSSI values depending on their orientation, thus being a poor choice for this application domain.