A geo-locked field device that is situated in a non-moving position and is operable as long as its position, including altitude and direction, is unchanged. If the position of the device is changed or disturbed, then the device will become inoperable. If the position is returned to its former position after being disturbed and rendered inoperable, then the device will continue to be inoperable. Providing a special signal to the device may cause it to become operable.