CurveLight: An Accurate and Practical Indoor Positioning System

This paper presents CurveLight, an accurate and practical light positioning system. In CurveLight, the signal transmitter includes an infrared LED, covered by a hemispherical and rotatable shade, and the receiver detects the light signals with a photosensitive diode. When the shade is rotating, the transmitter generates a unique sequence of light signals for each point in the covered space. The main novelty of the system design is a set of curves that define different regions, either transparent or translucent, on the shade. The regions allow the light signals to create patterns from which the receiver can calculate its angles with respect to the transmitter. We design the curves in such a way that the angular information is most robust to errors caused by signal noise and motor jitters. Moreover, the shade is divided into multiple sectors, each providing independent positioning function, so as to maximize the position update rate. Experiments in various environments show that the system achieves 2-3 cm accuracy on average, with a 36 Hz update rate with a single transmitter. We present a product quality implementation of the system, and report the deployment experience in real-world environments, including autonomous driving and robotics navigation. CurveLight consistently offers centimeter-level accuracy and low latency, serving as a key component of the hybrid navigation solution for real systems in challenging scenarios.