Super-Radar, Done Dirt Cheap
A radar system that uses ubiquitous cell-phone signals is on its way
Guess what- not only can you be tracked by using your cell as a locater(whether it's on or off), but these guys have come up with a way to track you using the signals from other cell phones as a sort of radar. Even FM radio signals could be used. OOOOH, isn't it scary kids?