Quick settling gyrocompass having interaxis decoupling compensation for improved response time

摘要

A quick settling, accurate gyrocompass for obtaining an accurate, short reaction time azimuth reference is described. The device preferably comprises a four gimbal configuration supporting a limited angle, two degree of freedom packaged gyroscope. The outer two gimbals of the arrangement are employed to provide a horizontal platform using accelerometers or pendulums as a reference to thereby comprise a stabilized platform. The inner two gimbals are employed to provide rotation about the two input axes of the gyro. The two degrees of freedom gyro and the inner two gimbals of the supporting structure thus comprised are connected to operate in a "North seeking" mode wherein the object is to align the gyro spin axis so that it is parallel to the spin axis of the earth. The gyro rotor is slaved to the gyro case about the gyro input axis so that if the rotor axis is not parallel to the earth axis a gyro error signal results in each input axis due to the rotation of the earth. These error signals are then used to drive the inner two gimbals until the errors are reduced to zero at which point (except for undesired effects) the gyro rotor spin axis will be parallel to the earth's spin axis thereby establishing the desired reference. Decoupling compensation circuits are employed for subtracting from the gimbal drive error signal supplied to the servo drive means of a particular axis, that component of the error signal which is due to gimbal rotation.