A device that is used to define a fixed direction in space or to determine the change in angle or the angular rate of its carrying vehicle with respect to a reference frame. Gyroscopes (also called gyros) respond to vehicle angular rates, that is, rates of change of angles between vehicle axes and reference axes, from which these angles can be computed. Gyros are used for guidance, navigation, and stabilization, for example, to measure the angular deviation of a guided missile from its desired flight trajectory; to determine the heading of a vessel for steering; to determine the heading of an automobile as it turns through city streets; to indicate the heading and orientation of aircraft during and after a series of maneuvers; and to stabilize and point radar dishes and satellites.