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What does the "w" in an IMU messag stand for?

asked 2018-09-03 09:01:36 -0500

vonunwerth gravatar image

Hello there, i use the Gazebo IMU-Plugin to generate sensor data of an IMU for my robot. An IMU message looks like the following:

header: ...
x: -9.881865455454e-324
y: -9.881865455454e-324
z: 8.8755655245457e-17
w: 1.0
orientation_covariance ...

I understand the x,y,z koordinates, but what does that "w" mean?

Thanks for your help.

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answered 2018-09-04 01:26:47 -0500

Raskkii gravatar image

The xyzw-coordinate is actually called a quaternion. It's a way of representing 3D rotations.

I suggest you read the wiki page:

And here's a useful link to visualize your quaternions and to also convert them to more understandable Euler angles:

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Asked: 2018-09-03 09:01:36 -0500

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Last updated: Sep 04 '18