This increase in assumed altimeter noise and reduction in accel noise has been flight tested by L.Hall with noticeable reduction in the immediate response to Baro errors during moving flight.
This increases the time constant of response to baro errors such that the pilot can more easily compensate.
The previous gain from rate to magnetometer error was excessive. The revised value is equivalent to a magnetic field length of 0.5 with a timing uncertainty of 0.01 sec
- inhibit switching from FLIGHT_NORMAL to FLIGHT_LAND_APPROACH until we meet stricter criteria other than just that LAND is next waypoint
- requires: nav bearing error < 10deg && have traveled path forward 30% of path && are below top of approach in case we hit waypoint while still descending
- exceptions: traveled path forward > 80% which basically means we're getting close to the flare point and better get into approach mode ASAP
Follow the following order for includes:
- Corresponding header file (if exists)
- System headers
- Other ArduPilot library headers
- "Local" headers (from the same library)
Testing on different platforms has shown that the new EKF has smaller innovations enabling innovation consistency checks that reject GPS and baro errors to be tightened.
The position and velocity thresholds for plane have been left the same because planes are less sensitive to GPS glitches as they fly higher and with more separation to surrounding objects. They are also more prone to bad inertial data due to the installation practices.
The altitude noise has been increased on plane to allow for the larger baro disturbances that result from the higher speeds and lack of a proper static pressure source. The innovation consistency gate has been adjusted to provide the same baro error limit of ~20m before baro is rejected.
Extended GPS loss can result in the earth field states becoming rotated and making it difficult for the EKF to recover its heading when GPS is regained.
During prolonged GPS outages, the position covariance can become large enough to cause the reset function to continually activate. This is fixed by ensuring that position covariances are always reset when the position is reset.
The innovation variance was being used incorrectly instead of the state variance to trigger the glitch reset.
Leonard Hall
Andrew Tridgell
ggregory8
Randy Mackay
Jonathan Challinger
squilter
Paul Riseborough
Tom Pittenger
Lucas De Marchi