People effects on WLAN-Based IPS´ accuracy experimental preliminary results

In order to enable Location Based Service (LBS) closed environment, many technologies have been investigated to replace the Global Positioning System (GPS) in the localization process in these indoor environments. WLAN occurs as the most suitable and powerful technology for Indoor Positioning System (IPS) due to its widespread and low cost. WLAN received signal strength (RSS) fingerprinting can be considered as the most accurate IPS method, but this accuracy can be decline due to WLAN RSS fluctuation. WLAN RSS fluctuates due to multipath influenced by obstacles presence. People presence under WLAN coverage can be considered as one of the main obstacles which can affect the WLAN-IPS accuracy. This research presents experimental results to show that the presence of one person between (Access Point) AP and (Mobile Device) MD decreases the Received Signal Strength (RSS) by -5dBm. This RSS decline can lead to big distance error more than 2m. Hence, any accurate IPS must consider the presence of the people in the indoor environment.