[KenWittlief]

in redundant systems each gyro would be read and used as if it is the only gyro in the system. The signals from all gyros are compaired. If they dont agree, one of them is wrong

with a dual system you have no way of knowing which one is wrong, so you must shut the system down

with a triple or quad redundant system, the gyro that disagrees with the rest is flagged as defective, and taken off line. The system can keep functioning until you get down to two.