50.5.1.1 States of the ESKF for estimating IMU pose

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Parent: IMU index

Source: Solà 2017 Quaternion kinematics for ESKF

Full state

Vector with 19 elements unknown_filename.1.png

The corresponding kinematics equations/motion model is given in  IMU kinematic equations/motion model .

Notes

  1. The angular error in 3D space is given by the notation $\delta\mathbf{\theta}$.

  2. (s.  rotation-error-representation )

  3. The angular error $\delta\mathbf{\theta}$ is defined locally w.r.t. the nominal orientation (classical approach used in most IMU-integration works).
    A more optimal approach may be to use a globally-defined angular error.

    A global definition of $\delta\mathbf{\theta}$ would lead to a composition on the left hand side (Hamiltonian convention)! unknown_filename.6.png

  4. The rotation estimate is not defined as an expectation [ markley-2014 ]

Inputs

IMU inputs, 6 element vector unknown_filename.png

Notes

  • The angular rate $\mathbf{\omega}$ is definned locally w.r.t. to the nominal quaternion
  • Enables direct incorporation of the gyrometer measurements $\mathbf{\omega}_m$ (which are in the body frame)