Angular Diversity Approach to Indoor Positioning Using Visible Light

A system for indoor localization using partially collimated light from individual LEDs inside a luminary is proposed, simulated and tested experimentally. A simple biconvex lens provides angular diversity to the luminary and generates multiple spatially separated regions of overlapping light which can be resolved with a single detector receiver. This approach provides location information without relying on signal intensity measurements, time-of-flight data or complex imaging approaches. The multiple LEDs available in each luminary are exploited to create a large number of uniquely detectable regions, enabling both low positioning error and low complexity. Using a model based on experimental measurements, in a prototypical $5\times 5\times 3$ m room the average positioning error is 26.0 cm using 4 luminaries and 12.9 cm with 9 luminaries.