Fusion with large initial magnetometer biases errors can result in the the NE earth field states reducing in magnitude and effectively flipping sign.
EKF: Move declination state limiting into a separate function
EKF: Limit NE mag states after each 3-axis mag fusion
EKF: Fix bug in mag field strength look-up scale factor
Ensures that each time the earth field covariance and variance data is reset, that the off-diagonal elements containing earth field declination angle certainty is restored.
Moves calculation only required for mag heading fusion into the if (_control_status.flags.mag_hdg) branch
When using EV yaw, the observed yaw angle is calculated directly from the EV quaternions using derived expressions from references in code comments.
Everywhere where KHP is used, it is first completely reset, thus making
it unnecessary to keep it as a class member.
This saves 2.3KB RAM.
Stack sizes don't need changing, since there is already a function
Ekf::predictCovariance(), which needs around 3KB of stack and is called
close to where the fuse* functions are called.
Perform the innovation consistency check on all axes first and exit if any axis fails. Reduces the likelihood of bad magnetometer data corrupting the attitude estimates.
The code fragments for the magnetometer fusion have been refreshed from the auto-coder.
Explicit floating point types used for constants.
The 3x24 observation Jacobian has been replaced with a 1x24 that is updated each axis iteration to save memory.
The covariance was not being updated with the observation from one axis before the innovation variance was calculated for the next axis. This results in greater weighting on measurements for subsequent axes.
Combines the forced symmetry, variance limiting and zeroing of covariances for unwanted states in the one function.
This ensures a consistent correction is applied after every covariance prediction or correction.
Daniel Agar
Paul Riseborough
CarlOlsson
Julien Lecoeur
Beat Küng
Paul Riseborough