Rapid resetting gyroscope

Claim 1

In a north-seeking gyroscope composed of a housing; a frame member journalled withiin the housing for rotation relative to the housing about a vertical axis; a gimbal member arranged within the frame member for rotation relative to the frame member about a substantially vertical axis; a gyro rotor journalled within the gimbal member for rotation about an axis substantially perpendicular to the rotation axis of the gimbal member for producing a force tending to align the rotor axis with geographic north; and servo means normally connected for rotating the frame with a selected degree of damping in a direction to establish a predetermined angular null position between the gimbal and the frame and a predetermined angular orientation of the frame corresponding to geographical north; the improvement comprising control means responsive to the value of a parameter indicative of the deviation of the frame from geographical north for temporarily rotating said frame at an increased rate, and with a degree of damping lower than such selected degree, in such direction only upon the occurrence of parameter values indicating that the angular deviation of said frame from geographical north exceeds a selected magnitude, said control means including: measuring means for measuring the value of such parameter; memory means for storing a representation of such measured value; and switching means operatively connected between said measuring means, said memory means and said servo means and switchable between a plurality of states for producing an operating sequence including: storing a representation of a measured value produced by said measuring means in said memory means; applying such stored representation to said servo means for producing such increased rate of frame rotation; and terminating the action of said control means.