Compass calibration vs heading reset

A wrong or drifting heading has two different fixes:

Compass calibration recomputes the magnetometer correction values (hard/soft-iron offsets and scales). It is persistent and fixes the sensor.

Heading reset re-seeds the current yaw estimate. It changes no calibration and fixes the estimate.

If the heading error returns after a reset, you need a calibration, or there is a magnetic disturbance near the sensor.

Calibrate the compass when

• The compass/IMU module or its mounting orientation changed.

• A payload, wiring, or structure near the sensor was added, removed, or moved.

• You moved to a region with very different magnetic characteristics (declination is handled automatically; this is about hard/soft-iron).

• Mission Control reports mag sensors inconsistent, or arming is blocked on a magnetometer check.

• The heading persistently disagrees with reality.

How: Vehicle Setup > Sensors > Compass

Diagnosis parameters (not normally touched in the field): EKF2_MAG_TYPE, EKF2_MAG_CHECK / EKF2_MAG_CHK_STR / EKF2_MAG_CHK_INC, COM_ARM_MAG_ANG, COM_ARM_MAG_STR.

Perform a heading reset when

• The vehicle was transported or powered up in a new orientation and the heading is wrong, but the compass is known-good.

• Initializing in GNSS-denied conditions and seeding yaw to a known true heading (e.g. catapult bearing).

• The heading briefly diverged and you want to snap the estimate back without recalibrating.

How: Vehicle Heading in the positioning drop panel in the fly view.

A heading reset never recomputes calibration. If the calibration is wrong, the error will reappear. Calibrate instead.