Localizing a wheelchair indoors with magnetic sensors

Indoor localization with conventional GPS devices is too difficult because the satellite signals are too weak. Several alternate schemes have been proposed, from RF signal strength to radio signatures. In this paper we consider the indoor localization of a wheelchair. This is important to guide the handicapped on predefined wheelchair-friendly routes in a building, for example. For indoor wheelchair positioning we explore a new odometry-like approach based on a cyclometer. Namely, the system detects wheel rotations from uniformly distributed magnets around the circumference of the two large wheels. Distance traveled and turning degrees can be computed by analyzing how much the wheels have rotated. This allows the tracking of the path. This paper reports the system implementation and preliminary results.