Indoor and Outdoor Positioning in Mobile Environments - a Review and some Investigations on WLAN-Positioning

This paper reviews existing indoor and outdoor positioning technologies for mobile users, including GPS and its extensions, wireless communication-networks and others. Accuracy and limitations of these technologies and methods are examined in more detail. Furthermore, results of own investigations concerning Wireless LAN are presented. 1 CLASSIFICATION OF POSITIONING METHODS FOR MOBILE COMPUTING Figure 1 provides an overview on existing and future indoor and outdoor positioning technologies for mobile users. Mobile computing is a combination of mobile Internet, communication, and position location and information technologies. The key to successful mobile computing is real-time positioning of the mobile user, enabling a large number of applications including wireless mapping, emergency response, fleet tracking, traveler information services, location-based marketing, etc. Depending on the task and the environment, mobile users may be positioned by different methods, which we will classify in indoor and outdoor methods. Even though, in general, the technologies are often divided into network-based or satellite-based systems (cf. Karimi et.al, 2004). Another classification is based on the actual device that performs the positioning solution, i.e., mobile user or the base station, leading to mobile terminal (user)-centric (such as GPS, A-GPS, E-OTD), network-centric (COO, TOA, TDOA, AOA, RSS, multipath pattern matching), or hybrid solutions. In the network-centric systems, the user’s position is determined by the base station or a control center and sent back to the user’s set, while in the terminal-centric solution, the position computation is performed by the user’s set. Position determination