What do gyros output?

Hey everyone!

Kind of stupid question - please bear with me (=

I want to keep track of the orientation of my gyro in respect to a ground fixed coordinate system. So just adding the rotation values from the gyro won’t be enough. I did some research and learned about quaternions and I am currently planning on updating the attitude by a quaternion multiplication. However, to do this, I need to convert the gyro output into a quaternion.

I was quick to google “Euler to quaternion” when I stopped for a second and thought: Do gyros output Euler angles?

I mean I know that the raw output is angle over time and that I need to multiply it with the time between samples. But when I have done that, what am I left with? Euler angles have as far as I know I specific sequence of rotations to them. And the angles are only valid with this specific set of rotations since you rotate the axis which are used for the subsequent rotations.

But a gyro measures all three rotation angles… at once I guess? So they can’t be Euler angles.

So how do I treat the output vales of a gyro and convert them into a quaternion?

Thank you for your help in advance and just say it if I am completely wrong here (=

Typical MEMS gyros output the rate of rotation about each of three axes.

In order to get the angle of orientation, you need a starting orientation, and integrate the rate over time to get the total change from the starting angles.

This process usually fails after just a few seconds, because MEMS gyros drift and the drift rate depends on temperature. To fix this, you add reference orientations obtained from a magnetometer and an accelerometer.

Note that there are several definitions for Euler angles, and two choices for the sign of a rotation about each axis.