Camera Assisted Received Signal Strength Algorithm for Indoor Visible Light Positioning

In this paper, a camera assisted received signal strength (CA-RSS) algorithm is proposed for visible light positioning (VLP) systems. The basic idea of CA-RSS is to simultaneously utilize visual and strength information of visible lights to achieve accurate positioning at low cost. With rectangular LED layout, the irradiance angles of the visible lights can be estimated regardless of the orientations of the LEDs. Based on the estimated irradiance angles, the distances between the LEDs and the receiver are obtained. Then, the two-dimensional (2D) position of the receiver can be calculated at low cost using a linear least square method. Based on the solid geometry theory, we further propose an independent solution method for three-dimensional (3D) positioning, which can avoid error propagation issue of dependent solution method. Moreover, considering the imperfect channel model in practice, we propose a calibration method of Lambertian model for practical uses. Simulation results show that the proposed approach can achieve 80th percentile accuracies of less than 10 cm for 3D positioning regardless of the orientations of the LEDs and the receiver. In addition, experimental results show that the proposed algorithm achieves an average 3D positioning error of 4.48 cm in a 70 cm × 70 cm × 140 cm space.