Implementation of indoor location and orientation estimation system using ultrasonic and radio

It is important for ubiquitous computing to realize providing location-aware information service for humans. Especially, orientation information can reflect a more detailed context than that obtained merely according to the location: people standing face-to-face or back-to-back would have vastly different contexts. We are tackling the indoor location and orientation estimation with a new approach called topological estimation that focuses on relative relationships of humans rather than their absolute positions. In the initial implementation of the topological estimation, we have used infrared tags as the sensors to collect real world relative information. However, there is a lower precision issue in the infrared system. To solve the issue, this paper proposes an ultrasonic system to provide higher sensing accuracy,