Affiliations: [a] Universidade de Sãao Paulo, PCS/EPUSP, Av. Prof. Luciano Gualberto, trav.3, n.158, 05508-900 São Paulo SP, Brazil | [b] Instituto Tecnológico de Aeronáutica, Divisão de Ciência da Computação, São José dos Campos – SP, Brazil | [c] Department of Computer Engineering, Universidade de São Paulo, Av. Prof. Luciano Gualberto, trav.3, n.158, 05508-900 São Paulo SP, Brazil
Abstract: The proliferation of mobile computing devices and wireless networks has set the stage for the development of smart environments rich in computing and communication capabilities, yet gracefully integrated with human users. This paradigm has fostered a growing interest in localisation-based systems and services for portable devices, especially in indoor environments. However, designing indoor localisation systems with increasing estimation capabilities and decreasing cost installation is a challenge. An interesting approach to reach such requirements consists in using the wireless local area network (WLan) infrastructure that is already installed in many places. Most reported WLan localisation approaches use a map of received signal strength and signal presence frequency collected from multiple channels at different physical localisations in the environment, which can be very noisy. This work proposes a new localisation system, WBLS (Wireless Based Localisation System), that considers the unreliability of information on signal presence frequency in the estimation process, in an attempt to eliminate its associated noise. Experiments considering mobile agents carrying devices and moving at human walk speeds show that the most important feature of WBLS is a robustness to access points shutdowns that may happen without any warning in an environment where there is little control over the infrastructure.
