Photo by Alex Lang
Sure, you have your GPS-enabled phone, a built-in navigation device in your car, and maybe even a TomTom for backup, but drop out of satellite range and you’re SOL. Researchers at North Carolina State and Carnegie Mellon Universities, however, have uncovered a way of putting you back on the map even if you’ve lost your signal. Their solution? Embedding a radar inside your shoe.
Photo by Quinn Dombrowski
CAN YOU FIND ME NOW?
Although GPS devices have been a godsend to the directionally challenged, they mean zip if you’re in a signal-free zone like an underground cave, a dense forest, or the subterranean depths of a shopping mall.
GPS devices mean zip if you’re in a signal-free zone like an underground cave or a dense forest.
One solution is using inertial measurement units (IMUs), which are electronic devices that measure how quickly you accelerate (or decelerate) to determine how far you’ve moved from your starting point. The problem is IMUs aren’t always accurate. If the device thinks you’re moving at 0.1 meter per second when you’re standing perfectly still, for instance, it can throw you off your actual position by 18 meters within three minutes.
Photo by Hillary Hartley
HOW ABOUT NOW?
To address the problem of accumulating errors, the scientists attached a portable radar sensor to a shoe. The radar is linked to a small navigation computer that tracks the distance between your heel and the ground, so if that measurement doesn’t change over a given period of time, the computer knows that you’re stationary.
To address the problem of accumulating errors, the scientists attached a portable radar sensor to a shoe.
“By resetting the velocity to zero during these pauses, or intervals,” says Dan Stancil, head of NC State’s Department of Electrical and Computer Engineering, “the accumulated error can be greatly reduced.”
In other words, on your next trip to the mall, you’ll know exactly how to get back to your car.
[Via Popular Science]