My name is Cristian and I m from Roumania.
First of all excuse my poor english and congratulations for this technical forum.
I started 2 weeks ago a new project with a autopilot Pixhawk/Px4 2.4.6.Everything went well ,I mean wiring and MP connection .The first test in MP,in 10 minutes I was surprised to see a movement of my boat on the map and i don't know if that normal.
Thanks in advance for your advises.
The boat movement on the map looks to be from a lack of satellites and high HDOP. Your screenshot shows only 4 sats and a HDOP of 9.6. As far as tuning PID's go you may be better off posting your question on Ardupilot.org.
David R. Boulanger