Wi-Fi-based indoor positioning: Basic techniques, hybrid algorithms and open software platform

In urbanized and indoor environments, outdoor positioning systems, such as Global Navigation Satellite Systems (GNSSs), are often inaccurate and adaptations of such systems to those contexts are expensive and hard to deploy. Nowadays, a lot of indoor positioning techniques have been studied, but it it quite difficult to objectively evaluate and compare their accuracies in the same environment. Our Open Wireless Positioning System (OWLPS) allows a comparison of indoor positioning algorithms and techniques with the same input data. Those techniques include propagation models, signal strength map, building topology, description of access points... Few algorithms use a Viterbi-like algorithm to take into account the pathway of the mobile terminal. This paper presents a new hybrid algorithm combining a signal strength cartography and a calibrated propagation model. Finally, we compare our solution with well known algorithms in order to evaluate the results in a real context.