Directional Gyroscope

(also azimuth gyroscope), a gyroscopic device for determining the angles of yaw (course change) and rotation of an object about a vertical axis. When the directional gyroscope is aligned with the plane of the meridian (for example, according to the readings of a compass), it indicates the current course of the object. The directional gyroscope is a free astatic gyroscope equipped with horizontal and azimuthal correction systems. The horizontal correction system, which holds the inner gimbal ring (axis of the gyroscope) in the plane of the horizon, consists of a pendulum corrector (which determines the angle of deviation of the gyroscope axis from the plane of the horizon) and a moment transducer (which applies the corresponding correction moments to the gyroscope). The azimuthal correction system, which holds the gyroscope axis in a fixed azimuthal direction (that is, at a given angle to, for example, the meridian plane), consists of a moment transducer and a computer, which provides the azimuthal correction moment. Corrections are introduced for the earth’s rotation and for the motion of the object relative to the earth. The azimuthal correction of the directional gyroscope may also be derived from a sensing element that is selective with respect to the direction to be stabilized—for example, a magnetic needle. The potentiometer serves to read off the angles of yaw and of rotation of the object about the vertical axis. The errors of a directional gyroscope are characterized by the azimuthal deviations of the gyroscope’s axis, which may range from degrees to tenths of a degree per hour.

Directional gyroscopes are used for determining the angles of yaw and rotation of aircraft and ships, as well as for short-term course indications. They may be used as the sensing elements of an automatic course stabilization system such as in the autopilots of aircraft, in automatic course controllers of torpedoes, and so on.