A method of calibrating a gyro (42) of a spacecraft (14) may include
determining a yaw attitude residual of the spacecraft. Roll gyro bias
residual is determined in response to the yaw attitude residual. The gyro
(42) is calibrated in response to the roll gyro bias residual. A method
of calibrating a gyro (42) of a spacecraft (14) may alternatively include
disabling gyro calibration, gain scheduling, or resetting attitude and
gyro bias covariance, for selective axes, for a yaw transient period. The
gyro (42) is calibrated in a nominal fashion after completion of the yaw
transient period.