Simplify calling so that it is only called in two ways:
1) Immediately before 3-axis mag fusion if not called since the last earth field covariance reset so that the earth field declination information can be formed.
2) Immediately after 3-axis mag fusion otherwise.
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.
* EKF angle constants in degrees for readability
* EKF make FILTER_UPDATE_PERIOD_MS static constexpr and add FILTER_UPDATE_PERIOD_S
* EKF controlOpticalFlowFusion() use constants and update comments
* EKF controlMagFusion() use angle in degrees
* EKF move earth spin rate to geo and update usage
* EKF: Fix numerical constant error and clean up comments
Comments do not need to contain numerical values when the code makes these clear.
* 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
This enables the initial uncertainty to be set based on application and also ensures that the max allowed growth in wind state variance is consistent with the initial uncertainty specified.
Use horizontal acceleration to check if yaw is observable independent of the magnetometer.
Use rotation about the vertical to check if mag raises are observable.
If neither yaw of mag biases are observable, save the magnetic field variances and switch to magnetic yaw fusion.
Use the last learned declination when using magnetic yaw fusion so that the yaw reference remains consistent.
When yaw or biases become observable, reinstate the saved variances and switch back to 3D mag fusion.
Add a bitmask parameter to control bias learning for individual axes. This is achieved by setting the disabled states to zero together with their corresponding covariances.
Minor cleanup of the covariance prediction comments.
Removal of unnecessary variable copy operations.
Replace index operations to initialise covariance to zero with the more efficient memset.
Use vertical velocity and position innovation failure to detect bad accelerometer data caused by clipping or aliasing which can cause large vertical acceleration errors and loss of height estimation. When bad accel data is detected:
1) Inhibit accelerometer bias learning
2) Force fusion of vertical velocity and height data
3) Increase accelerometer process noise
The previous practice of relying on the off-diagonals being zero caused problems with conditioning of the magnetometer fusion on one flight. By storing the variances when the learning inhibit becomes active and ensuring that the rows and columns in the covariance matrix for the inhibited states are always zero, the observed numerical conditioning error has been eliminated for replay of the problem flight log .
This bug caused X and Y delta velocity bias state variance to be reset to the same value as the Z axis when learning was inhibited.
Documentation has also been updated.
Enables wind estimation without an airspeed sensor and enables synthetic sideslip to be used with an airspeed sensor for improved wind state estimation.
Wind states and covariances are reset differently depending on whether airspeed is available.
Convert uncertainty in initial rotate vector into quaternion covariances using symbolic toolbox derived expressions.
Enable setting of initial angle uncertainty via a parameter
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.
Paul Riseborough