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High-accuracy VLC-based indoor positioning system using multi-level modulation.

In this study, a novel high-precision positioning algorithm was proposed by using Visible Light Communication (VLC) with only a simple and single receiver. The received voltage-level difference with multi-level modulation was adopted as the input variable, in order to minimize the negative consequences of noise. Then, the relationship between the received voltage-level difference, noise, and position was developed based on the optical propagation model. The minimum mean squares error algorithm and extended-Kalman filter was employed in order to improve the accuracy of the optical model and achieve high performance. Using the developed algorithm, high-accuracy results with a 0.9 cm average position error in the simulation and 2.56 cm average position error in the practical experiments were obtained.