A 3D indoor positioning system based on common visible LEDs

We propose a realistic 3D positioning system for indoor navigation that exploits visible Light Emitting Diodes (LEDs), placed on the ceiling. A unique frequency tone is assigned to each lamp and modulates its intensity in periodic time slots. The Time Difference of Arrival (TDOA) is measured without the need of a synchronization system between the sources and the receiver, then it is used to accurately estimate the receiver position. We first describe the theoretical approach, then propose the model and characterize the possible sources of noise. Finally, we demonstrate the proof-of-concept of the proposed system by simulation of lightwave propagation. Namely, we assess its performance by using Montecarlo simulations in a common room and estimate the impact of the different implementation parameters on the accuracy of the proposed solution. We find that, in realistic conditions, the technique allows for centimeter precision. Pushing the device requirements, the precision can be further increased to a sub-centimeter accuracy.