W. Muttitanon
Asian Institute of Technology,
Thailand
Email: [email protected]
N. Tripathi
Asian Institute of Technology
Email: [email protected]
M. Souris
Asian Institute of Technology
Location or positioning is a crucial issue to initiate a location based application. Determination of an accurate position has been a research issue for many years. There are 3 categories: global location systems, wide-area location systems based on cellular networks and indoor location system. Global position system (GPS) receives signals from multiple satellites and employs a triangulation process to determine physical location. GPS fails to provide locations for indoor use or in urban areas where high building shield the satellite signals.Wide-area location systems based on cellular mobile systems involve measuring the signal strength; the angle of signal arrival and/or the time difference of signal arrive and is highly limited by the cell size. Several approaches have been proposed for indoor location sensing; such as infrared sensing, radio frequency, ultrasonic, and scene capture analysis. Each of these methods has their own advantages and disadvantages. Some are expensive to implement, while others are not very accurate. In this study a wireless local-area network (WLAN) based positioning system has been employed for distinct advantages over all other system. It is an economical solution because of the existence of the WLAN network usually as part of the communications infrastructure. The position system can be implemented using software in notebook computers, personal digital assistants (PDA), or the other mobile devices equipped with WLAN capability. The WLAN covers a large area compared with other types of indoor positioning systems. The system employs an underlying wireless data network, such as the IEEE 802.11 wireless network, to estimate user location has gained attention recently, for indoor applications and do not require additional hardware for user location determination.
