Many people use GPS systems for navigation. As they have improved GPS systems have become increasingly beneficial to those who are blind but indoor navigation is difficult when satelite signals are blocked.
Researchers at Stanford University have come up with a promising new carrier for GPS signals -- TV signals.
The next logical step seems to me to be integrating RF band in a handheld that reads RFiD chips thus creating a navigation device for those with visual impairments that works indoors and outdoors and can identify specific objects (via RFid chips).
For more information see:
R.U.R. - Rosum's Universal Reconnaissance
http://glikglik.blogspot.com/2005/05/rur-rosums-universal-reconnaissance.html
Rosum TV-GPS
http://www.rosum.com/