Indoor positional tracking using dual-axis rotating laser sweeps

摘要

Accurate positioning of objects within an indoor environment is essential for applications such as virtual reality, robotics and multirotor drones. Previous methods of obtaining six-degrees-of-freedom for a tracked object have been susceptible to latency and accumulated error, computationally intensive, inaccurate, costly, or required exotic components, setups and calibration procedures. This paper presents a novel architecture and implementation of an indoor tracking system that consists of a rotary-laser base station and a tracked object equipped with photodiode sensors. The base station emits horizontal and vertical laser lines that sweep across the environment in sequence. The base station also emits an infrared synchronization beacon that floods the environment between each sweep. The tracked object consists of multiple photodiode sensors and a processing unit. Based on the timings between the synchronization beacons and the sweeps observed by each photodiode, along with the known configuration of the photodiode constellation, the position and orientation of the tracked object can be determined with high accuracy, low latency, and low computational overhead. In addition, the system allows a large number of such objects to be tracked within the same space, as each tracked object can be a separate embedded device. The Nikon iGPS tracking system, along with the more recently announced Lighthouse technology from Valve Corporation, use multiple base stations to triangulate a tracked object, while we will show that one is sufficient for basic tracking. In addition, this paper is the first to describe the specifications for a low-cost version of such a system. Observations and performance characteristics of the constructed prototypes are discussed.