Patent GB-683777-A (GB)
Title: Compensated vertical gyroscope system
IPC: G01C19/44
Filed: 1950-05-25
Abstract: 683,777. Gyroscopic apparatus. BENDIX AVIATION CORPORATION. May 25, 1950 [June 10, 1949], No. 13227/50. Class 97 (iii). [Also in Group XXXV] In a gyroscope system for use on a moving craft and having pendulous means for precessing the support mounting the gyroscope for angular movement about its bank axis, the pendulous means are rendered inoperative in response to the rate-of-turn of the craft when the craft changes direction and precessing forces determined by angular and linear velocities of the craft and the bank of the craft are applied to precess the gyroscope support to maintain the spin axis in a predetermined position, e.g. vertical. The pendulous means may also be rendered inoperative for precessing the support about the pitch axis in response to charges in linear velocity of the craft so that the gyroscope acts as a free gyroscope about its pitch axis. An indication of the true vertical is obtained corrected for errors due to Coriolis acceleration by a signal proportional both to the latitude at which the craft is moving and to the linear velocity of the craft. As shown, a computer device 23 responsive to dynamic and static pressure data and temperature data produces a signal V proportional to the linear velocity of the craft. This signal is applied to relay R to open the circuit of the bank axis precessing motor 5 to render inoperative the pendulous device 9 when the craft changes velocity. An inductive signal device or synchro 25 produces a signal E BA  which is a function of the bank angle and is applied to a synchro 31 the rotor of which is secured to the frame 33 mounting a rate-turn gyroscope 35 having a servomotor 39 opposing angular displacement of the frame 33 whereby the signal E BA  is modified to Ew in proportion to the angular turn velocity W of the craft. This signal Ew from the stator of synchro 31 is impressed on the stator of a synchro 43 the rotor 45 of which is angularly adjusted proportionally to the signal V by the computer 23 and produces a signal Ewv from rotor 45 proportional to angular and linear velocities of the craft. Signal Ewv is fed to one stator of a resolver synchro 49 and a reference voltage E3 is fed to another of its stators. The resolved amplified voltages from rotor 53 after amplification in amplifier 50 are impressed on motor 51 which drives the rotor 53 to null position through an angle B=tan<SP>-1</SP>KWV, K being a constant of proportionality and B the theoretically correct angle between the dynamic and true verticals during turn of the craft. Rotor 57 of synchro 55 is turned by motor 51 through a similar angle. Signal E BA  is applied to the pendulous rotor 61 of a differential synchro 59, an output signal from the stator representing the actual angle between the true and dynamic verticals. This signal is applied to the stator of synchro 55 the rotor of which is mechanically coupled with rotor 53 so as to provide a signal EN from synchro 55 which represents the difference between the actual angle between the true and dynamic vertical and the correct angle and represents the banking error of the craft and is impressed on the precessing torque motor 7. A potentiometer 65 is set in accordance with sin A, A being the latitude of the craft position, to produce a voltage E sin # which is fed to the rotor 71 of a synchro 69 which rotor is connected mechanically to computer rotor 23 to give an output signal Ec of the stator proportional to V sin # which is applied to the synchro rotor of bank angle repeater 73 to the stator of which signal EBA is applied. A servomotor drives the rotor of the synchro to null position and gives an indication of the bank angle corrected for the Coriolis error. In an alternative arrange. ment a constant voltage is applied to the stator of synchro 69 and the rotor output signal is multiplied by a synchro having its rotor rotated by an air position or ground position indicator computer through an angle # to give a voltage EC1 proportional to V sin #. In a modification the voltage Ec is algebraically combined with voltage EN and fed to the bank processing motor 7 and to the bank repeater 73. Specification 660,208 is referred to.