In Ardusub version of QGC, GPS is not implemented as well as in other branch. GPS signal don’t travel underwater!
Nevertheless, there is now some underwater localisation GPS and the AUV position now appear on QGC map even while flying under the water. The actual position is refresh live but it still not possible to see a live track of were I was 1, 2 or 5 minutes ago or during the whole mission. I can only access this information at the end of the day using the replay tlog file option.
Do you know if live trace is implemented in one or the other version of QGC (copter, plane, rover, boat). I mean can you see the actual track of were your drone is and was during the mission? It could be a serie of dot or even better a small smoothed line running through the previous coordinates. If it exist in other QGC branch, I would like to use it has an example to add this feature in Ardusub.