Magnetometer calibration

Hi, I am trying to use Olympe to take-off and control the anafi 4k. For the majority of flights the olympe code fails to launch/take-off the drone; connecting the RC to the phone and opening Free flight 6 then prompts a magnetometer calibration. After finishing the calibration on the freeflight app, the drone does successfully launch. However, after landing, the drone displays the same behaviour and another calibration process is needed before we can launch the drone. Any reason why the calibration is prompted so frequently and any ways around it in olympe? Thanks!

Hi @m.arthur ,

This really is driven by the environment. If you are in a place with large metal structures or even if there are significant metals in the ground, they can all affect the magnetometer. Basically before for every flight with Olympe or GroundSDK, we check the calibration and gps lock with the free flight app. Without calibration, the drone will not fly autonomously, but you can still manually pilot it.


Hi @teiszler,

Thanks for your reply. You’re correct in that the environment was in close proximity to metal structures. However, is it still normal to require calibration before each flight even if the environment hasn’t changed? Any way to store the calibration data from one flight to the next through olympe? We also tried to take-off manually using the take-off button on the RC which didn’t work either until the calibration was carried out through the free flight app. Thanks again!


There is a magnetometer in the drone, so naturally this instrument will be affected any time there is magnetic interference. As such, it doesn’t make sense to be able to store this data as it is ephemeral and dynamic. As far as flight, I may have been slightly wrong with what I said. I believe the drone has to be calibrated before taking off manually, however you can still manually fly even if the drone is actively receiving magnetic perturbations (FreeFlight will display a red warning message on the display when this is occurring). However if there are magnetic perturbations the drone will not be able to autonomously fly via Olympe/GroundSDK. In those cases, you would have to move the drone to a different location to resolve the magnetic interference before Olympe/GroundSDK will succeed in taking off.

Thanks for the explanation @teiszler.

Lucky the issue seems to have fixed itself. Further testing in the same environment doesn’t flag up the need to calibrate the magnetometer after every flight. The only thing that was done differently was a calibration of the magnetometer (prompted) and gimbal (not prompted by the app but done anyways) through the free-flight app at the start of the day, following which we were able to take and land multiple times through olympe without needing to calibrate the compass again.

:+1: You also often have to recalibrate when you change batteries.