Patent ID: 6152403
Filing Date: 2000-11-28
Classification: B64G,G01C

Abstract:
A method of calibrating gyroscopic drifts of gyroscopes which each generate an output signal that represents rotation about a respective axis of a spacecraft, said method comprising the steps of:inhibiting spacecraft rotation about at least one of first and second spacecraft axes;from its output signal, calibrating each gyroscope whose respective axial rotation has been inhibited in said inhibiting step;for any uncalibrated gyroscope, slewing said spacecraft under control of another gyroscope so that it rotates by a slew angle in a plane defined by the uncalibrated gyroscope's respective axis and the respective axis of a calibrated gyroscope;for a selected time period, controlling the spacecraft's attitude with said uncalibrated gyroscope to thereby generate an attitude error angle;backslewing said spacecraft under control of said another gyroscope by a backslew angle that is substantially equal and opposite to said slew angle;measuring said error angle; andcalibrating said uncalibrated gyroscope from said slew angle, said selected time period and said error angle.