Indoor visible light positioning method based on three light-emitting diodes and an image sensor

Indoor positioning systems have been gaining traction in recent years, and visible light positioning (VLP) may be the most promising technology. We propose an indoor VLP method based on three light-emitting diodes and an image sensor. We regard the lamp plane composed of three lamps as a rigid body and the process of lamp plane imaging as the process of rotating and scaling the rigid body. By solving the matrix transformation, the two-dimensional (2-D) coordinates and azimuth angle of the image sensor are obtained with the focal length of the image sensor unknown. Azimuth angle plays an important role in other positioning methods, such as pedestrian navigation methods. The experimental results show that the 2-D positioning maximum error is only 3.21 cm in the horizontal condition, and the azimuth angle error is within 5 deg when the tilt angle is <7 deg.