Use accelerometers and gyroscopes to increase accuracy of location with with virtually no power increase. It would also allow navigation through tunnels and such when GPS location is lost. It would also prevent erroneous movement while stopped at a traffic light. There are companies testing this type of technology. One that I have been following but have no financial interest in is navisens.com There are videos from navisens at https://www.youtube.com/user/navisens