Towards a position and orientation independent approach for pervasive observation of user direction with mobile phones

This paper presents a novel approach for mobile phone centric observation of a user’s facing direction, relying solely on built-in accelerometer and magnetometer. Our approach achieves greater accuracy and independence by an automatic detection of the wearing position of the mobile device on the user’s body and subsequent selection of an optimum strategy for estimating the user direction. We report on a detailed analysis of various features sets and classifiers in order to determine an optimum selection of those for recognizing the wearing position and evaluate the accuracy and reliability of our overall implementation through an extensive measurement campaign.