Bayesian Receiver Orientation Steering for Indoor Visible Light Positioning

Abstract

Received-signal-strength (RSS) visible light positioning (VLP) with a single photodiode (PD) usually assumes an upward-facing receiver. This convention simplifies the channel model, but it leaves receiver orientation unused even though orientation changes RSS sensitivity and LED visibility. We study a two-measurement localization cycle: an initial upward RSS vector gives a coarse position estimate, and we then orient the PD before acquiring a second vector. We use expected posterior localization mean-square error to motivate the sensing decision and develop two efficient local-information policies. Point scores the coarse estimate, whereas Stencil examines a nine-point neighborhood while enforcing LED visibility. After steering, we jointly fit the upward and steered RSS vectors for every policy. Using common Monte Carlo realizations and paired bootstrap intervals, we compare the policies with fixed upward reception, random steering, center pointing, and maximum-predicted-RSS steering. In 4-LED and 6-LED rooms, both local-information policies reduce RMSE by 18–20% relative to fixed upward reception; in an 8 m room, the reductions are about 40%. We further compare the selected actions with a finite grid-posterior reference and examine sensitivity to stencil parameters and actuator rotation error. The reference confirms that Point and Stencil are Bayes-risk-motivated surrogates, not exact Bayes optimizers.