- EKF isTimedOut(), isRecent(), and isNewestSampleRecent() need to handle the case where the timestamp has never been set
- reset() more thoroughly reset fields (mainly impacts unit tests)
- from the C standard, "All identifiers that begin with an underscore and either an uppercase letter or another underscore are always reserved for any use"
- refactor all EKF backend output predictor pieces into new OutputPredictor class
- output states are now calculated immediately with new high rate IMU rather than after EKF update
- IMU delayed sample is passed as around as control data to avoid storing an extra copy and make the requirement clear
- move EV yaw and EV position to new state machines
- EV yaw and EV pos now configured via EKF2_EV_CTRL (migrated from EKF2_AID_MASK)
- new EV position offset estimator to enable EV position while GPS position is active (no more EV pos delta fusion)
- yaw_align now strictly means north (no more rotate external vision aid mask)
- automatic switching between EV yaw, and yaw align north based on GPS quality
- respect new EKF2_EV_CTRL parameter for VPOS usage
- EV hgt rotate EV position before usage (there's often a small offset in frames)
- EV hgt reset use proper EV velocity body frame
- try to keep EV hgt and EV vel state machines consistent
- small incremental piece of https://github.com/PX4/PX4-Autopilot/pull/19128
- don't store unnecessary IMU copy in class, pass it through where required
- remove custom pi constants
- remove unused fields from ahrs_ekf_gsf (vel_NE, fuse_gps, accel_dt)
- explicitly initialize everything in header
- apply PX4 code style
- set GPS velocity before yaw estimator update, not after
- in a lot of cases this won't really matter, although you can see it in logs (especially with things like vehicle_at_rest), but it's something we might as well do properly
Co-authored-by: Mathieu Bresciani <brescianimathieu@gmail.com>
During the whole flight, if the difference between the yaw estimate from
EKF2 and the emergency estimator is large and that the GNSS velocity
fusion is failing continuously, immediately reset to the emergency yaw
estimate.
- with Ekf::initialiseFilter() resetting _time_last_hagl_fuse the terrain estimate was technically valid regardless of any range or flow data availability and as a result optical flow fusion is able to start and stay active
- only consider terrain estimate valid based on control status flags and recent fusion
- buffer at least 2 samples for the IMU output predictor buffers
- dropping below 2 becomes problematic for the minimum observation
interval calculation and the vertical output buffer trapezoidal
integration
Daniel Sahu