Gyrocompass

gyrocompass

gyrocompass, navigational instrument which makes use of a continuously driven gyroscope to accurately seek the direction of true (geographic) north. It operates by seeking an equilibrium direction under the combined effects of the force of gravity and the daily rotation of Earth. As such, it is immune to magnetic interferences such as those caused by ore deposits, steel structures, or electric circuits. These properties make the gyrocompass a prime navigational device in ships and submarines. It has found extensive use on ore ships on the Great Lakes, as the azimuth reference for gun and torpedo control on warships, and as a reliable compass for navigation of any ship. It is not suitable as an aircraft compass because the speed of several hundred knots associated with such vehicles seriously affects the north-seeking properties of the instrument.

Although the apparent effect of Earth’s rotation on gyroscopes was first shown by Léon Foucault in 1852, the ability to construct sufficiently accurate units did not exist until the first decade of the 20th century. The first seaworthy gyrocompass was produced in 1908 by the firm of Hermann Anschütz-Kaempfe in Germany. It was largely made possible through the efforts of Max Schuler, who developed the principles on which a practical shipborne gyrocompass depends. This compass was a marvel of mechanical ingenuity. In 1911 Elmer Sperry in the United States produced a gyrocompass that was easier to manufacture. In England, Sidney George Brown, working with John Perry along similar lines as Sperry, produced a gyrocompass in 1916. Later the Arma Corporation in the U.S. produced a unit that was a modification of the Anschütz.

All gyrocompasses operate on the same basic principle. They differ in their methods of supporting the gyroscopic element (the spinning wheel) and of applying the pendulosity which is required for the north-seeking property and in the means used to damp out oscillations and thus cause the unit to settle on north.