Using RFID Tags as Reference for Phone Location and Orientation in Daily Life

This paper investigates a novel approach to obtain location and orientation annotation for smartphones in real-life recordings. We attached RFID tags to places where phones are located in daily life, such as pockets and backpacks. The RFID reader integrated in modern smartphones was used to continuously scan for registered tags. In a first evaluation across several full-day recordings and using nine locations, our approach achieved an accuracy of 80 % when compared to a manual diary. Only 5.3 % of all tags were missed. We conclude that RFID-based location and orientation tagging is a viable option to obtain ground truth reference for real-life activity recognition algorithm developments.