“The system, dubbed Navigational Assistance for the Visually Impaired (NAVI), can provide location information for the visually impaired and for other kinds of navigational assistance applications like self-guided tours. The system includes a set of permanently mounted passive transponders and a reader/playback device carried by the user. Rather than tipping off an inventory system when a specific item is near, a transponder trips a particular CD track when a playback device comes within range. The system could be a low-cost alternative to global positioning system-based schemes for providing location-specific information and pedestrian navigational assistance.”