ORIGINAL: S_Ellzey
For what its worth - the gyros in an Inertial Measurement Unit (IMU) are at 45 degrees to the major axis'. Of course there are 3 gyros and a computer to come up with the final answer. An IMU is the device in a missile, airplane, or sub that tells it how it is moving.
And of course it's the 3 gyros and the computer that makes the difference! Mounting any gyro off its perfect axis means it will respond to rotations in the other axes too, so it is not well suited to our purposes. By using 3 gyros and a computer, the computer can compare the readings from all 3 to realise that the vehicle is actually just rotating in one axis, or the relevant amounts in each axis. Whilst it may seem a complicated way of doing what we get from 3 gyros on perfect axes, it does provide redundancy, comparison between different gyros to improve accuracy and so on.
H