A study on the use of Wi-Fi positioning technology for wayfinding in large shopping centers

With the popularity of the Apple-, Android- and Windows Operating System-based smart phones and tablets, application programs (APPS) targeting a spectrum of location-based services (LBS) are available on the market. The positioning support of these applications are largely based on satellite positioning with, for example, the American global positioning system (GPS), the assisted GPS combining GPS and cellular mobile network positioning (CMNP), and the integration of GPS, CMNP and Wireless Fidelity (Wi-Fi) positioning technologies. The advantage of the combined and the integrated approaches is that CMNP and Wi-Fi positioning can supplement GPS in case satellite positioning fails in dense and highly obstructed areas and indoors. However, the few tens to hundreds meters achievable accuracy of the market available CMNP and Wi-Fi approaches is not sufficient for the LBS applications that require more accurate users' positions in real time, such as wayfinding in large shopping centers. A study was conducted in Hong Kong by making full use of the available public Wi-Fi networks inside a large shopping center to locate mobile users' positions in real time with sufficient accuracy for wayfinding. The proposed Wi-Fi positioning method is based on the ranking pattern of a set of received signal strengths (RSSs). The test results show that the proposed method is feasible and cost-effective to provide real-time positioning accurate to shop level. However, further improvement of the method is necessary to address the problems of nuisance Wi-Fi signals transmitted from other floors, and the possibility of receiving very similar RSS ranking patterns along the same corridor.