In this mode, the mag is used to inilialize the heading.
During flight, the heading is predicted using gyros and corrected
by GNSS measurements if available.
- fake_pos only if at rest or tilt variances becomes large
- fake pos: don't run when grav fusion is enabled
- gravity fusion enabled by default
- gravity: only fuse when accel norm and lpf norm are consistent
Co-authored-by: bresch <brescianimathieu@gmail.com>
Use flow rates instead of integrals in backend. This allows us to delay
the data to the mitpoint integration time and simplifies the code in
general.
Gyro compensation can still be done in EKF2 if needed, but the
flow module normally already appends the correct gyro data to the flow
message.
- in theory these are helpful to ensure EKF2_HGT_MODE configuration is
consistent with the relevant aid source (GPS, baro, etc), but it can
be a little awkward with users having to fight manual parameter
changes in the right order
This estimate doesn't converge to the true yaw but can be used as a
more consistent but drifting heading source.
It can be used by a setpoint generator to adjust its heading setpoint
while the true yaw estimate is converging in order to keep a constant
course over ground.
- when GNSS is used require low mag heading innovations during
horizontal acceleration (yaw observable) to validate the mag
- only fuse mag heading just enough to constrain the yaw estimate
variance to a sane value. Leave enough uncertainty to allow for a
correction when the yaw is observable through GNSS fusion
- split mag_3d into new standalone mag fusion and mag fusion allowed to update all states (full mag_3d)
- new dedicated control logic for mag/mag_3d fusion and standalone mag heading fusion
- if WMM available use for mag_I and mag_B init
- mag states reset if external yaw reset (yaw estimator, GPS yaw, etc)
- mag reset if declination changed (eliminate _mag_yaw_reset_req)
- mag fusion (but not mag_hdg or mag_3d) can be active during gps_yaw or ev_yaw (if yaw aligned north)
Co-authored-by: bresch <brescianimathieu@gmail.com>
- since last_us is set to 0 every time the bias is not observable, the
total time was also reset -> needed 30 consecutive seconds in mag 3D
to be declared "stable"
- after landing, the mag_aligned_in_flight flag is reset. Using this for
bias validity makes it invalid before we have a chance to save it to
the calibration.
Opt flow raw innovations can be really large on ground due to the small
distance to the ground (vel = flow / dist). To make the pre-flight check
more meaningful, scale it with the current distance.
bresch