The gyro data accumulation needs to be across the same integration period as the flow sensor. The previous code didn't sample the accumulation until the midpoint of the flow data had fallen behind the fusion time horizon.
This PR changes the optical flow time stamp definition so that flow data is retrieved when the leading edge of the flow accumulation period falls behind the fusion time horizon. This enables the accumulated gyro data to be sampled at the correct time. Fusion is then delayed until the mid sample time has fallen behind the fusion time horizon.
This is required because it can take several seconds for an optical flow sensor operation to be confirmed and there are also many use cases for indoor operation where no optical flow is used.
If magnetometer use is being inhibited because an indoor condition has been detected (optical flow and poor or no GPS) and the optical flow fusion checks fail causing the EKF to stop navigating, we do not want the EKF to start using the magnetometer.
Remove duplicate checking for dead reckoning and consolidate into a single function.
Use separate timers to check for start of dead reckoning and check when dead reckoning has been performed for too long for the nav solution to be valid.
Allow the timeout for validity reporting to be adjusted externally.
Separate external reporting of dead reckoning from internal checks.
* EKF: Move optical flow specific state reset to helper functions
* EKF: Ensure loss of optical flow aiding is handled correctly
If data is only source of aiding and has been rejected for too long - reset using flow data as a velocity reference.
If flow data is unavailable for too long - declare optical flow use stopped.
Use consistent time periods for all resets
* EKF: Ensure loss of external vision aiding is handled correctly
If data is only source of aiding and has been rejected for too long - reset using data as a position.
Don't reset velocity if there is another source of aiding constraining it.
If data is unavailable for too long, declare external vision use stopped.
Use consistent time periods for all resets.
* EKF: Update parameter documentation
Make the distinction between the no_gps_timeout_max and no_aid_timeout_max parameters clearer
* EKF: make class variable units consistent with documentation
* EKF: Don't reset states when optical flow use commences if using external vision
* EKF: Stop optical flow fusion when on ground if excessive movement is detected.
* EKF: fix terrain estimator vulnerabilities
Reset estimate to sensor value if rejected for 10 seconds
Protect against user motion when on ground.
Fix unnecessary duplication of terrain validity check and separate validity update and reporting.
* EKF: remove unnecessary Info console prints
Optical flow use information can be obtained from the estimator_status.control_mode_flags message
* EKF: fix inaccurate comment
* EKF: remove duplicate calculation from terrain validity accessor function
* EKF: Do not delay reversion to no-aiding mode if parameter initiated
* EKF: Move no-aid reversion resets to helper functions
* EKF: Prevent unwanted fusion of velocity data during no aiding mode
* fix typo
* EKF: use baro if it was reset to baro from ev
* EKF: set vert_pos_reset if resetting to ev hgt
otherwise the position controller will not reset the setpoint -> leading to unwanted altitude changes
This enables the EKF to use an additional NE velocity measurement. This can be used to improve position hold stability when landing using a beacon system for positioning by fusing the beacon velocity estimates.
Apply a dead-zone to the vertical position innovation if using baro for height and if in the ground effect region during and just after takeoff.
Method needs to be activated externally.
Turns off automatically after 10 seconds or if specified height gained.
