The VMS is intended for use as a vehicle motion sensor. The electronic components covered by this specification are military unique because they must be able to operate satisfactorily under accelerations of 40 g applied in any direction, and at ambient temperatures ranging from -50°F to +200°F. Commercial electronic components are not designed to withstand such extreme and sudden environmental conditions and would experience catastrophic failure. The VMS supplies pulses, representing incremental distance traveled, to the Dynamic Reference Unit Hybrid (DRUH) or other navigation devices. The DRUH is an inertial navigation system that uses VMS data to damp inertial errors and sense vehicle motion. The DRUH is described by MIL-PRF-71185.