A wireless LAN-based indoor positioning technology

Abstract

Context-aware computing is an emerging computing paradigm that can provide new or improved services by exploiting user context information. In this paper, we present a wireless-localarea-network-based (WLAN-based) indoor positioning technology. The wireless device deploys a positiondetermination model to gather location information from collected WLAN signals. A model-based signal distribution training scheme is proposed to trade off the accuracy of signal distribution and training workload. A tracking-assistant positioning algorithm is presented to employ knowledge of the area topology to assist the procedure of position determination. We have set up a positioning system at the IBM China Research Laboratory. Our experimental results indicate an accuracy of 2 m with a 90% probability for static devices and, for moving (walking) devices, an accuracy of 5 m with a 90% probability. Moreover, the complexity of the training procedure is greatly reduced compared with other positioning algorithms.

WLocator: An Indoor Positioning System

“…The second category uses empirical data to approximate the location (e.g., [1], [2], [17], [19], [20]). An early example of a location positioning system that uses empirical data is RADAR [2].…”

“…The work in [1], [20] attempt to address this issue using interpolation techniques for location estimation.…”

“…Examples of positioning systems are found in [1], [8], [9], [19], [17], [20]. Several of these systems provide high granularity (i.e., locations that are close to each other can be distinguished) but often incur a high cost of deployment since a thorough mapping of the environment is required in advance.…”

Enhanced Fingerprint-Based Location Estimation System in Wireless LAN Environment

“…When a RSS tuple is obtained in real-time, it is matched to these probability distributions to find out the location with the highest probability. The HORUS system by Youssef et al [12] [13] [14] [15] , and the system by Xiang et al [16] are probabilitybased WLAN positioning system, and both systems use the downlink approach to obtain the RSS tuples.…”

Positioning LBS to the third dimension

“…In the last couple of years, location fingerprinting techniques using WLAN have been suggested for indoor areas where GPS does not work well (Keamarungsi et al, 2004, Xiang et al, 2004. Generally, the deployment of fingerprinting based positioning systems can be divided into two phases.…”