The speed of light shouldn't be too fast if the fob is just returning a ping. The car can almost certainly wake up the fob, ping it, then compute the distance.

The speed of light shouldn't be too fast if the fob is just returning a ping. The car can almost certainly wake up the fob, ping it, then compute the distance. Unless my brief calculations [1] are too simplistic, a 2Ghz processor would have a resolution of increments of 15cm. That should be plenty of resolution to decide if the key is in a certain spot. [1] https://www.google.com/search#q=speed+of+light+%2F+2+ghz https://www.google.com/search#q=speed+of+light+%2F+2+ghz