i have a quaternion representing a small angle rotation (i.e. the scalar part (q4 say) is approximated to 1). This quaternion is estimated in a Kalman Filter, so i also have the associated covariance matrix P, giving me the covariance of the error in the other thee quaternion components (q1, q2, and q3), and thus the expected error in my rotation estimate.(adsbygoogle = window.adsbygoogle || []).push({});

I need to know the expected error rotation around a given vector, h, given the above. Can anyone tell me how to calculate this? I am looking for a scalar that is the variance of the angle phi representing the likely degree of rotation around this vector h.

Hope i explained that clearly! So just like i could take a 2D position error covariance matrix in x-y for example, and work out the expected error variance in any given direction, i want to do the same thing for the rotation and quaternion. Probably a simple answer, but i want to make sure i am doing the right thing...

**Physics Forums - The Fusion of Science and Community**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Covariance of small angle quaternion

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

Loading...

Similar Threads for Covariance small angle | Date |
---|---|

I Dx as a small change in x | Mar 20, 2018 |

A The Pantheon of Derivatives | Feb 25, 2017 |

A Help with covariant differentiation | Jun 26, 2016 |

Negative values in covariance matrix | Aug 10, 2008 |

**Physics Forums - The Fusion of Science and Community**