Alliedsignal Inc.

The Bendix Corporation

Raymond M Bendett

Michael J Lanni

Howard E Schulien

Thomas Beneventano

A gyrocompassing system intended for land based equipment requiring north reference information includes a novel gyrocompass implementation which enables utilization of high grade inertial sensors while achieving the desired goal of moderate cost. The north finding system is designed to provide high accuracy with fast reaction time over a wide temperature range without the aid of heaters and other auxilliary equipment. The arrangement is specifically configured to tolerate settling and/or oscillatory base motion without additional reaction time or degradation of gyrocompassing accuracy.

North finding system

Apparatus is operable gyroscopically to determine direction and to determine north. This apparatus includes a case (34), a gimbal (20) and a central gyro (10). The gimbal (20) is rotatably mounted in the case for rotating azimuthally. The central gyro (10) has transverse to its spin axis (16), a single degree of rotational freedom. This central gyro (10) is mounted in the gimbal (20) to rotate about its spin axis (16) and shift the degree of freedom between a vertical (12) and a horizontal (18) axis. The central gyro (10) has a transducer (28) and a torquer (26). The transducer (28) can sense motion about the single degree of freedom and can provide a deflection signal signifying this motion. The torquer (26) is connected to the transducer (28) and can respond to its deflection signal for applying a torque to the central gyro (10) tending to affect motion about the single degree of freedom, when this freedom is oriented along the vertical axis (12). The apparatus may be used to determine north when the single degree of freedom is vertical. The torque required to restrain motion about this degree of freedom can be measured. Thereafter, the spin axis (16) can be rotated azimuthally by 90 degrees and the torque required to restrain motion about the degree of freedom remeasured. The north to south direction is estimated by applying the torque measured before and after the 90 degrees of azimuthal rotation to a predetermined trigonometric formula.

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Ridgewood, NJ, United States of America

Raymond M Bendett