Researchers at the Sarnoff Corporation in Princeton, New Jersey claim to have built a better GPS system, one that'll never fail, even when confronted with impenetrable obstacles like tall buildings, tunnels, and for the spelunkers among you, caves. The secret ingredient, it seems, is a new video processing technology the Sarnoff researchers have developed, which makes use of two forward-facing and two rear-facing cameras placed on a vehicle or helmet that capture stereoscopic video to help determine the location of the vehicle when the GPS goes dark. The complete workings of the technology are still under wraps, but according to the MIT Technology Review
, the system can pinpoint the position of a vehicle or individual to within one meter after traversing a half a kilometer without access to GPS. As you can probably guess, there's no indication as to when the technology might actually be available for public consumption, although based on the source of funding, the Office of Naval Research, you can safely bet that the military will get its hands on it before you or we do.