Problem in Loiter - Identifed in Dataflash need help on fix

I am running APM 3.2-rc7. My quadcopter fly’s perfectly in Alt hold mode. I switch to Loiter and it will loiter perfectly in one spot. When I begin to move it will do a sharp roll and I have to switch back to Alt hold mode to prevent a crash. I have looked at all the logs and identified where the error happens.

I have attached an image of the log where the problem happens. The DesVelX vs VelX and DesVelY vs VelY don’t track properly. It looks like when I need to go left it goes right. How do you fix that?

The .log and .tlog are attached.


To me it looks normal.
Need to turn up your logs so we can see other data such as motor out and RCIN.


No, that’s not normal at all. He most likely has some kind of compass problem, but I really can’t get much info because the logs don’t have enough data. Unfortunately, the APM logging just isn’t good enough anymore.

I would check the compass alignment, compass calibration, CompassMot. And I wonder if you can turn on Mag datalogging (though I still don’t think that will give us much useful info).