Estimation of Object Position and Orientation for Dimmable Visible Light Positioning

This work investigates how to estimate the position as well as the orientation of an object in an indoor environment with Light Emitting Diode (LED) ceiling lamps that may be independently dimmed. A receiver with three Photo Diodes (PDs) and angular diversity is used to measure Received Signal Strengths (RSSs) with respect to each LED lamp. To support light dimming, these RSSs are normalized and used to estimate the orientation angle relative to each LED lamp. In particular, the normalized RSS vector is compared in terms of the cosine similarity with the RSS reference vectors for orientation angles of 0, 1,…, 359 degree. Based on these relative orientation angles, the receiver position as well as its absolute orientation (with respect to the positive y-axis) are next estimated using the least square error criterion. Simulation experiments with nine LED lamps on the ceiling of a room (10 m wide, 10 m long, 2.75 m high) and random object positions and orientations at the height of 0.75 m from the floor show that, for 90% of the time, the position error is within 0.6 m while the orientation error is within 4 degree.