RSSI-Based Real-Time Indoor Positioning Using ZigBee Technology for Security Applications

Abstract

Localization in indoor environments is an important aspect with regard to mobile security applications. Because here, the global positioning system (GPS) is not available or very imprecise, other positioning systems are required. For that matter wireless sensor networks provide two common approaches based on received signal strength indicators (RSSI). The first one uses fingerprints and the second is based on trilateration. Because fingerprinting needs a lot of training and (re-)calibration, this paper presents a new indoor positioning system based on RSSIs and trilateration using ZigBee technology. Since RSSI measurements are very susceptible to noise, the gathered RSSIs have to be preprocessed before they can be used for position calculations. For this reason, the RSSIs were averaged using time-dependent weights and smoothed over time so that outliers and old RSSIs can be eliminated. The presented indoor positioning system was verified by experiments. © Springer International Publishing Switzerland 2014.