VLC-IPS: A Visible Light Communications Based Indoor Positioning System

Abstract

Indoor positioning has always been a hot topic in research in order to accurately determine an object's position indoors for applications such as navigation, tracking, inventory management, and security. However, there are many limitations that can severely reduce the performance of any RF or GPS based indoor positioning system (IPS). This paper proposes a visible light communications based IPS based on Received Signal Strength and the Trilateration method with Linear Least Square. The proposed system consists of 4 white LEDs placed at the ceiling of a room and a photo diode receiver at the ground terminal. Additionally, Unique Frequency ID modulation technique is utilized to modulate the 4 white LEDs, and a bandpass filter and FFT are utilized to obtain the received signals' strength at the photodiode. The proposed system is simulated and evaluated with and without external interference sources. Result show that the average positioning error was found to equals 2.02 cm with no interference. While the average positioning error was measured to be 13.9 cm, in the case where multiple sources of interference were present.