Abstract: 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.

Abstract: 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).