@SapoLab, Looks like a fun project. Did you resolve the steering oscillation problem? I have something similar which is preventing me making any progress - actually, the problem is not that similar as mine is much higher frequency with a more stable period. It is documented here: BuoyBots - self position holding buoys for RC sail boat racing . I’ve downloaded your log files. I see no loiter mode in the 13 Sept log, though there is a guided mode. The 10 Sept log shows a loiter period where the behaviour doesn’t look too bad - certainly better than mine.