True north for measuring gyro device

摘要

PURPOSE:To reduce the required measuring time while simplifying the operation eliminating intial state procedure by controlling a torque unit from a declination and a time differentiation to rest a gyro section. CONSTITUTION:A gyro rotor 1 is suspended on a body 10 through a suspension line 8 at the upper portion of a rotor case 2. As a gyro section starts a precession with the rotation of the earth, the direction of a mirror 3 changes and a sensor 4 feeds an output equivalent to a declination alpha of a gyro rotor shaft from the sensor zero direction to a torque unit control circuit 5, which feeds an output -K(alpha+Td.dalpha/dt) to a torque unit. The torque unit applies a torque about a vertical shaft to the gyro section through a control plate 7. The gyro section separates by a certain angle epsilon with respect to the sensor zero direction and rests. The angle epsilon is connected to an azimuth theta of setting the body and the value theta is computed with a CPU9 from the output of a sensor 4 equivalent to the angle epsilon.