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
This is a functionally equivalent. It moves all of the code for the terrain estimator into a single function call from the main filter update, making it clear that it is independent of the main filter.
Taking off before passing GPS checks would cause airspeed or sideslip to be fused when the filter was still using a constant position assumption. This would cause large airspeed innovations, invalid wind estimates and degrade filter performance after GPS was gained and position and velocity was reset.
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.
- if both gps position and velocity measurements are rejected for 7 seconds
do a reset
- if only gps position measurements are rejected then wait for 14 seconds
as we still have velocity measurements to constrain the drift in position
- introduced ecl internal parameter for the timeout
Signed-off-by: Roman <bapstroman@gmail.com>
All the decision for a sensor are made within a specific function for that sensor and when there is data to process at the fusion time horizon.
Information and warning messages are improved.
Wait until enough height has been gained to be clear of ground based magnetic anomalies. Failure to do so can result in incorrect earth field initialisation.
Convert quaternion covariances into an angular alignment variance vector and discard the z component so that yaw uncertainty does not affect the result.
When transitioning into optical flow nav from a non-aiding condition during ground operation, ensure position covariances are reset as they could be invalid.
