Abstract: A calibration system produces a calibrating signal having an adjustable amplitude, a torque force representative of that amplitude is directly applied to a meridian seeking gyroscope unit that hangs from a suspension band. Prior to each use of the instrument, the signal amplitude is adjusted so the gyroscope unit assumes a predetermined null position. The torque force is applied to the gyroscope unit by inductive field interaction of the first, second, and third coils. A control signal representative of the displacement of the gyroscope unit from the null position is applied to the third coil, which is fixed relative to the null position. The calibrating signal is applied to the first coil, which is also fixed relative to the null position. The axis of the first and third coils are both in an approximately perpendicular relationship to a vertical axis.

Abstract: A gyroscope unit having a horizontal spin axis hangs from a suspension band within a container. The container is rotatably supported about a vertical axis. A transducer generates a control signal representative of the angular displacement between the gyroscope unit and the container about the vertical axis from a reference position. The container is rotated about the vertical axis responsive to the control signal to reduce the angular displacement from the reference position. A torque about the vertical axis that opposes the angular displacement is directly applied to the gyroscope unit responsive to the control signal. The directly applied torque is a nonlinear function of the angular displacement, being zero below a threshold value of angular displacement and having a predetermined gradient above the threshold value.

Abstract: The instant system describes a heading and attitude reference system for an aircraft in which slaving of the directional gyro to the magnetic compass and roll erection of the vertical gyro is cut off during turns which exceed a predetermined rate. A unique feature of the system is the manner in which the turn rate cutoff rate signal is generated from the directional gyro without incorporating either rate gyros or rate generators. The turn rate cutoff signal is generated from the directional gyro heading signal by converting the heading signal electrically into a signal proportional to turn rate. In one embodiment, the heading signal from the directional gyro which is representative of the heading shaft angle (.theta.) is converted into a plurality of signals proportional to the sine and cosine of shaft angle .theta.. These signals are first differentiated and then vector summed to produce a signal directly proportional to the rate of shaft rotation (d.theta.

Abstract: An angular displacement transducer having a mounting base for mounting an inertial element sensitive to low frequency angular displacements and an inertial element sensitive to high frequency angular displacements. The low frequency sensitive inertial mass is a solid rotor device having a pickoff for sensing angular displacement between the solid inertial mass and the mounting base. A feedback centering circuit responsive to the pickoff output maintains the solid inertial mass in a substantially neutral position relative to the mounting base for displacement frequencies below the band of interest and allows the solid mass to move in an open loop fashion within its band of interest. The inertial mass sensitive to high frequency angular displacements is a fluid mass having a pickoff for sensing displacement of the mounting base relative to the fluid mass.