초록 ▼

Spacecraft cost, volume and weight are reduced with gyroscope calibration methods that can be effected with structures (e.g., a single-axis Sun sensor and a wheel system) which are typically carried by spacecraft for other purposes. In a method embodiment, these methods include an initial step 1) of

Spacecraft cost, volume and weight are reduced with gyroscope calibration methods that can be effected with structures (e.g., a single-axis Sun sensor and a wheel system) which are typically carried by spacecraft for other purposes. In a method embodiment, these methods include an initial step 1) of calibrating a selected gyroscope and subsequent steps for each uncalibrated gyroscope of: 2) slewing the spacecraft by a slew angle and controlling attitude with the uncalibrated gyroscope for a selected time period to thereby couple its drift into the inertial axis of a calibrated gyroscope, 3) backslewing the spacecraft to return the calibrated gyroscope to its inertial axis, and 4) measuring an error angle generated by the uncalibrated gyroscope during the selected time period (e.g., with a Sun sensor or with the calibrated gyroscope). In another embodiment, steps 2-4 are replaced by steps of: 5) orienting a momentum vector to inhibit spacecraft rotation about an uncalibrated gyroscope's respective axis, and 6) calibrating the uncalibrated gyroscope from its output signal. Another method embodiment retains steps 5 and 6 but replaces the initial step 1) by repeating steps 5 and 6 with a different momentum vector. Drift components are thus sensed in two different spacecraft planes and these components are mathematically resolved to find gyroscope drifts.

대표청구항 ▼

[ We claim:] [1.] 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;f

[ We claim:] [1.] 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.