A Smart Cane-Based Indoor Positioning System for Visually Impaired People

Autonomous navigation is a crucial aspect of the visually impaired community’s pursuit of independence and social equity. To achieve this goal, visually impaired people (VIP) require a navigation and wayfinding system that works both outdoors and indoors. While outdoor navigation can rely on ubiquitous signals such as global navigation satellite system (GNSS), indoor navigation presents a significant challenge, especially in unfamiliar environments. Despite over two decades of research and development, the issue of delivering a high performance and cost-effective indoor positioning solution for VIPs remains unresolved. Bluetooth-based angle of arrival (AOA) positioning is a cost-effective method that offers accuracy ranging from upper decimeters to meters. However, it still faces challenges in detecting and mitigating outliers caused by nonline-of-sight (NLOS) and multipath effects during signal propagation. In light of these challenges, this article proposes a novel dead reckoning aided AOA Bluetooth indoor positioning system that utilizes a smart cane. The developed model takes into account the swinging characteristic of the cane, which is integral to visually impaired individuals’ mobility. Furthermore, this article incorporates a novel outlier detection and exclusion layer to reduce the impact of NLOS and multipath effects. The proposed system’s performance was evaluated through a series of experiments, and the positioning error distribution was analyzed. The results showed that the accumulated probability of errors less than 0.5 m was 93.56%, and 99.64% of errors were within 0.7 m. With the demonstrated high level of accuracy, the proposed system presents a promising solution for indoor navigation for VIPs.