The EKF has taken its first heading from the compass
What ArduPilot says:
- EKF3 IMUN MAGN initial yaw alignment complete
- EKF2 IMUN MAGN initial yaw alignment complete
The copy of the EKF (ArduPilot's position and attitude estimator) for this IMU has set its heading for the first time, from the compass with this number (MAG0 is the first). It follows tilt alignment at once, provided the aircraft is not being turned. It is a ground alignment: the heading is as good as the compass is at that spot, so steel under the aircraft makes it wrong. A copter aligns again 2.5 m up (“in-flight yaw alignment complete”). If this line never comes, the EKF has no compass it may use.
Parameters to look at
| Parameter | What it is |
|---|---|
EK3_SRC1_YAW | Yaw Source |
COMPASS_USE | Use compass for yaw |
Where to do it:Setup & Tuning Guide
The code that sends it
EKF3 IMUN MAGN initial yaw alignment complete
libraries/AP_NavEKF3/AP_NavEKF3_MagFusion.cpp NavEKF3_core::controlMagYawReset() · Open in ArduPilot Copter-4.7.1
EKF2 IMUN MAGN initial yaw alignment complete
libraries/AP_NavEKF2/AP_NavEKF2_MagFusion.cpp NavEKF2_core::controlMagYawReset() · Open in ArduPilot Copter-4.7.1