The accelerometer is also the base of any
inertial navigation system such as some aircraft
autopilots, or ship nav systems. A set of accelerometers continually measures acceleration in all
three dimensions; the second
integral (thanks
baffo!) of these values will give you the distance traveled in each direction from the starting point (well, not that simply, but using that method).
Many accelerometers utilize gyros of some sort, from mechanical gyroscopes to ring laser gyros.