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gyromagnetic compass[¦jī·rō·mag′ned·ik ′käm·pəs]
a gyroscopic device used on moving objects and designed for determining the course of the object with respect to the plane of the magnetic meridian. It is a free astatic gyroscope equipped with azimuthal and horizontal correction systems. The azimuthal correction system, which contains a magnetic needle as the sensing element, holds the gyroscope axis in the plane of the magnetic meridian. The horizontal correction system holds the inner gimbal suspension ring in a position perpendicular to the outer ring. The horizontal correction system consists of a potentiometer and a moment transducer. The azimuthal correction system consists of a magnetic needle, a potentiometer, and a moment transducer. The operational principle of the correction systems of the gyromagnetic compass is analogous to that of the vertical gyroscope with a pendulum correction. The error of the gyromagnetic compass may be as high as several degrees. The instrument is widely used in aeronautics, as well as the navy.
If the magnetic system is installed far from the gyroscope, the coupling between them is achieved by a servomechanism (remote-control gyromagnetic compass). In some existing instruments the magnetic system is replaced by an induction sensing element. This is the so-called gyroinduction compass. In contrast to the gyromagnetic compass, it does not contain an azimuthal gyroscope, and the magnetic course indications are determined using an induction sensing element consisting of a permalloy core and a winding. The axis of the element is fixed in the plane of the magnetic meridian. To increase the accuracy of the instrument, the induction element is stabilized with respect to the plane of the horizon by installing it on the chamber of a vertical gyroscope.
A. IU. ISHLINSKII and S. S. RIVKIN