Developing, Implementing, and Verifying the Integrity of an Indoor Navigation System for Visually Impaired People

There are an estimated 250million visually impaired individuals worldwide(Ackland\_et\_al\_2017), many of whom use a cane to help them get around. The most familiar type of cane, known as a "long cane", is used by visually impaired individuals with extremely restricted or no vision to help them find their way and avoid obstacles. However, a long cane can only detect obstacles below knee height and within approximately 1 m of the user. This makes it particularly challenging for visually impaired individuals to navigate safely in busy urban areas, especially where cars, bicycles, and pedestrians are found in close proximity.

To address this challenge, WeWALK have developed a revolutionary "smart" device that screws onto a user's existing cane. Our cane detects obstacles(e.g.,trees) at knee-to-head height and uniquely connects to a user's smartphone(Android/Apple) to provide audio-based navigation via integration with Google Maps.

However, our existing audio-based navigation relying on GPS cannot be used indoors and does not provide sufficiently high spatial resolution with the level of confidence(integrity) required to help visually impaired individuals independently navigate indoor urban spaces such as transport hubs and shopping centres.

Recent indoor navigation systems rely on detecting Bluetooth signals transmitted from "beacons" installed across an indoor space. Beacon signals are detected by smartphones and other Bluetooth-enabled devices and can be used to locate the user, warning them, for example, when they are approaching escalators, ticket barriers, and platforms. Such beacons have been trialled with Transport for London since 2015\. However, to date, they have not demonstrated adequate system performance(accuracy/reliability/usability) for use in a safety-critical application such as enabling a visually impaired user to navigate, avoiding hazards, around a tube station using beacon signals alone.

Here, WeWALK in collaboration with Astra-Terra (a London-based SME specialising in intelligent transportation systems), the Centre for Transport Studies at Imperial College London, and the Royal National Institute for the Blind will address the technical/safety challenges that have prevented widespread uptake of beacons for indoor navigation. We will build on the existing installed base of beacons and the available open standard by developing a novel integrity-monitoring layer (providing safety-critical functionality) and usability framework, detecting the beacons signals directly with our smart cane to provide high-accuracy, turn-by-turn indoor audio-based navigation. This project has the potential to play a vital role in ensuring that the rising numbers of visually impaired people have full access to the urban spaces where we live, work, and play.