I have a sensor (3 axis gyroscope) which can rotate and measure angular velocity in 3 dimensions (aligned with the sensor). I know what its current orientation is with respect to the world frame. Call this quaternion qs. I take a reading from my gyroscope and integrate it to give me a rotation in the sensor frame. Call this quaternion qr.
I now want to apply the rotation qr to the current orientation qs to obtain the new orientation, qs'. But I cannot use qr directly as it describes a rotation in the sensor body frame.
I need to transform my rotation quaternion into the world frame, and then I could just apply it to the orientation i.e. qs' = qs * qr_world. But I am really struggling to understand how I can perform this transformation qr -> qr_world.
Does this even make sense? I wonder if I have fundamentally misunderstood some concepts here. If it does make sense, then I am specifically interested in understanding how to do this using quaternion operations (if that is possible) rather than rotation matrices or euler angles.
qrare fundamentally different, where the former represents orientation (in reference to the outside world) and the latter represents a mere rotation (without any external reference at all). You can think of
qras the delta to get to
qs'. Therefore, there is no need for somehow further translating anything. $\endgroup$
qs'will be given by
qs' = qs * qrThe way I am thinking of it now (and I hope that this is correct) is that the orientation quaternion
qsalready describes the rotation required to move from the world frame to the sensor frame, so the further rotation
qrcan just be applied directly to that. @Biscuits if you put this in an answer I will accept it. $\endgroup$