Three-Dimensional VLC Positioning System Model and Method Considering Receiver Tilt

In recent years, several indoor positioning systems have been extensively studied for environments where a satellite signal is typically degraded and interrupted. Among them, visible light positioning (VLP), which has several advantages such as the absence of electromagnetic interference, energy efficiency, and high bandwidth availability, has received considerable attention. However, most VLP systems are established based on two-dimensional (2D) positioning methods in which the height of the receiver is fixed or restricted and the tilt of the receiver is not considered. To solve these problems, we propose a new positioning method that can be applied to three-dimensional (3D) space. We first formulate a new mathematical model for a 3D VLC positioning system and derive the channel gain as a function of source and receiver location in Cartesian coordinates. By employing the cost function developed using the induced channel gain, we demonstrate that the proposed 3D method is more accurate compared to the 2D method in experiments. The quantitative results show an average error of 7.95 cm, in a 2.5 m × 2.5 m × 3 m region.