We discuss requirements surrounding a mobile navigation system for visually impaired people. We describe an initial prototype
based on a PDA using GPS location tracking. This prototype has so far failed to provide reliable location detection, due to
the use of GPS in built up environments. We discuss how our system may improve detection by switching between a range of different
location tracking
... [Show full abstract] technologies. However, we conclude that there may still be times when these technologies fail, and more
work is needed on how to support the user in such circumstances.