A Novel Visible Light Positioning System Based on the Dual-LED Anchor

Recently, indoor localization has played a crucial role in the construction of smart homes, smart buildings, and smart cities. Numerous localization technologies have been investigated, and visible light positioning (VLP) as one of the representative technologies has drawn much attention due to its high accuracy, low cost, and friendly infrastructure. Aiming to solve the prominent issues faced by the traditional VLP ranging-model-based localization method, a phase-difference-based ranging method assisted by a dual-light-emitting diode (LED) anchor was first proposed, which can eliminate the negative influences of hardware heterogeneity, environmental differences, and receiver's inclination angle effectively. The key point of the proposed solution is that we innovatively designed an anchor integrated by two closely spaced LEDs replacing the two separated LEDs for distance calculation, which contributed to avoiding the workload of the ranging model's calibration and the dependence on frequency exchange. Furthermore, a weight matrix was introduced in the final localization to restrain the significant error and increase the confidence coefficient of reliable observations. Finally, a brief analysis of the proposed method's theoretical performance was presented and evaluated by extensive experiments. The proposed method was illustrated to be a very competitive system, which obtained a centimeter-level localization accuracy, and showed more advantages than the traditional ranging method, especially when the photodiode (PD)'s inclination angle is not zero.