Vertical measurable displacement approach for altitude accuracy improvement in 3D visible light positioning

Visible light positioning (VLP) techniques using light-emitting diodes (LEDs) are mostly based on the assumption that the height of the receiver is fixed and not intended to be measured. We evaluate the received signal strength (RSS)-based positioning with changed receiver altitude in both two-dimensional (2D) and three-dimensional (3D) situations, taking into account of non-line-of-sight (NLOS) channel with first reflection. Simulation results show that, the positioning accuracy deteriorates with the increase of the receiver altitude. To alleviate such problems and locate the target more accurately, we proposed a simple and convenient method by intentionally changing receiver altitude with direct measurable displacement. By employing the proposed approach, the resultant altitude error can be limited within ∼34 cm.