Indoor Positioning System Based on LED lighting and PSD Sensor

This paper shows a system and a method for indoor positioning based on the LED lighting installed on the environment. The proposal is based on the modulation of the visible light signal emitted in frequencies ranging from 50 to 200 kHz and detection by means of a PSD (Position Sensitive Detector) photodiode. The paper describes the mathematical modelisation of the proposed Indoor Positioning System (IPS), considering that the detector will move on a planar surface. Several synthetic results are shown for distances of 1 and 3 meters between the light source and detector. The positioning technique is based on the angle of arrival (AoA) captured from the LED lighting. Using genetic algorithm, we have obtained the model parameters for the detector (composed of a PSD and coupled lens). Different experimental tests have been carried out to determine the precision in positioning with the proposed system, considering a ceil lighting at 3 meters distance, with a coverage surface area of 3x3 m2. The average error results in the positioning of the detector, with low multipath (MP) effect, are below 1 cm in 80% of the tested points. Considering the presence of strong effects of multipath signals, the maximum positioning error remains below 4.5 cm.