To pass from invalid to valid:
- time hysteresis
- some vertical velocity
- test ratio < 1
- low-passed signed test ratio < 1
To pass from valid to invalid:
- low-passed signed test ratio >= 1
At each new valid range measurement, the time derivative of the distance
to the ground is computed and compared with the estimated velocity.
The average of a normalized innovation squared statistic check is used
to detect a bias in the derivative of distance measurement,
indicating that the distance measurements are kinematically inconsistent
with the filter.
- the estimated mag bias was requiring > 30 seconds of continuous 3d
mag fusion to be reported stable (and saved back to mag cal), this
restores the original intent requiring 30 seconds of accumulated valid
3d mag fusion
- this is a more conservative default if a vehicle isn't set (no land detector running)
- handled horizontal preflight failures in commander when disarmed
rather than overloading xy_valid and v_xy_valid flags
- ekf2 no longer depend on arming or standby status
- ekf2: expose dead reckoning as control status flags
- commander:
- add GPS validity check
- in AUTO MISSION if dependent on GPS then a loss of GPS will
- Also use the delayed current data instead of newest that might not be
available (gps buffer is sometimes empty if the dt between samples is
larger than the delayed horizon).
- Separate "baro fault" from "baro intermittent": intermittent is a
temporary failure and should prevent from switching to baro right now,
but "fault" means that it should never be used anymore
- In case of height timeout, check for metrics but not for consistency
as the filter is likely to have diverged already.
- move vehicle at reset detection ekf2 -> land_detector
- ekf_unit: reduce init period
- Fake fusion is when at rest is quite strong and makes the variance reduce rapidly. Reduce the amount of time we wait before checking if the variances are still large enough.
- ekf_unit: reduce minimum vel/pos variance required after init
- Fake pos fusion has a low observation noise, making the vel/pos variances reduce quickly.
Co-authored-by:: bresch <brescianimathieu@gmail.com>
- remove class _mag_sample_delayed
- update mag fusion call graph to use mag sample delayed functionally
- Ekf::resetMagHeading()
- use low pass mag directly, but check if valid (magnitude)
- MAG_FUSE_TYPE_INDOOR treat like auto if heading required
- introduces new parameter EKF2_PREDICT_US to configure the filter
update period in microseconds
- actual filter update period will be an integer multiple of IMU
The existing logic using the angle between velocity vectors failed to
determine a yaw failure in practice because the state velocity is often
too small compared to its uncertainty to be used. In all the failures
reported, the yaw emergency estimator converged properly and yaw reset
would have fixed the issue.
A much simpler check using the yaw difference between the main EKF
and the emergency estimator is now used to tell if the vel/pos update
failure is most likely caused by a wrong heading.
bresch