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