The height of the take-off field above sea level was set, or could not be
What ArduPilot says:
- Field Elevation Set: N.Nm
- Failed to Set Field Elevation: Armed
To turn pressure into height accurately ArduPilot needs to know how high above sea level the field is. “Field Elevation Set” says which height it now uses: taken by itself from the EKF origin (the first good GPS position) while disarmed, or from BARO_FIELD_ELV if you set it. That line is information only. “Failed to Set Field Elevation: Armed” means BARO_FIELD_ELV was changed by more than 1 m while armed: the change was refused and the parameter put back.
What to do, most likely first
BARO_FIELD_ELVwas written while the aircraft was armed, by hand or by a ground station that sends it automatically.FixSet it while disarmed, or leave it at 0 and let ArduPilot take the height from the GPS.
Parameters to look at
| Parameter | What it is |
|---|---|
BARO_FIELD_ELV | field elevation |
The code that sends it
Field Elevation Set: N.Nm
libraries/AP_Baro/AP_Baro.cpp AP_Baro::update_field_elevation() · Open in ArduPilot Copter-4.7.1
Failed to Set Field Elevation: Armed
libraries/AP_Baro/AP_Baro.cpp AP_Baro::update_field_elevation() · Open in ArduPilot Copter-4.7.1