We am testing our ROV in a pool. We are trying to practice control by going up and down along the tile walls. To do this we keep our ROV on stabilize mode. However, we notice that the ROV does not stay perpendicular to the wall as we fly laterally after we set it on stabilize mode. A number of factors could contribute to this. But one thing we have noticed is that QGroundControl says something along the lines of “Mag Anomaly.” Are we correct in thinking that the onboard compass is detecting a magnetic field in the pool? And this magnetic field has an effect on the stabilize mode that is altering our heading as we get close to the wall?
The rebar in the pool can throw the compass off, when there is some constant unexpected/unexplained offset then the autopilot will realign/recalibrate the compass to the new offset.
It is an issue with physics that is difficult to mitigate. If performance is required in harsh magnetic environments, more compasses can be added externally for better filter results.