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.
Use a new method that preserves the roll and pitch information and adds the uncertainty for yaw only.
Ensure that correlation information to non-quaternion states is removed when a reset occurs to prevent fusion of subsequent observations (e.g. GPS) causing incorrect yaw.
EKF waits 10s after GPS signal is lost before setting GPS control status flag to false. As the position information given by the alternative position sources drifts from the last GPS position, the controller over corrects.
With this update, the time horizon until GPS control flag set to false is reduced and only alternative position source is used for estimation.
tested with optical flow as position souce
log from as is https://review.px4.io/plot_app?log=d624af5e-dde4-40ab-ba5b-a693a49f5a36
log with update https://review.px4.io/plot_app?log=13ed6dc3-22dd-43f8-b898-4add41d60439
Previously, the reset of the yaw when climbing above 1.5m was not performed until 3-axis fusion was enabled. This could result in loss of navigation depending on the value of EKF2_MAG_TYPE and the flight profile.
- the velocity of the optical flow sensor relative to the IMU expressed in
body frame is the cross product of the angular velocity with the vector
from IMU to the sensor. If we use the angular velocity stored in the flow
sample struct we need to use a negative sign as that angular velocity
follows the opposite sign convention.
Signed-off-by: Roman <bapstroman@gmail.com>
- _flt_mag_align_complete was not set when choosing pure 3D mag fusion.
one effect of this was that the declination used in the filter was not
the one calculated from the magnetic field states.
Signed-off-by: Roman <bapstroman@gmail.com>
The handling of invalid flow data when on ground is performed in controlOpticalFlowFusion() where it is able to handle flow sensors that don't publish gyro data.
Heading data is assumed to be from a dual antenna array at a specified yaw angle offset in body frame, but with the heading data already corrected for antenna offset. The offset is required to apply the correct compensation for combined rotations and to determine when the yaw observation has become badly conditioned.
The parameter used to control the maximum dead reckoning time had 'gps' in the parameter name which was confusing because it was used for all measurement types capable of constraining horizontal velocity error growth. The parameter variable has been renamed and the documentation for it improved.
The parameter used to control the maximum time since fusing a measurement before the measurement is considered to be not contributing to aiding had misleading documentation which has been updated.
* terrain_estimator : guard against case where latest range sample is newer than IMU sample
* EKF : control : correct detection of no optical flow fusion over a time period
