Are there any academic publication describing the low pass filter using quaternion?

[mathieudutoursi]

I am mathematician by background and I wonder what this low pass filter is supposed to achieve.

Also, I wonder if there are other techniques for this problem.

[michaelestanley]

The closest would be SLERP (Slerp - Wikipedia).    The thinking behind our filter is in AN5022 in the sensor fusion docs directory.  Look at section 6.