Hi, I am using ArduCopter 4.6.3 firmware. I take off quite aggressively from the ground with EKF sources not using GPS at all, only compass, in Stabilize. When reaching roughly 30m I lower to a bit below hover to slow down the copter and enable GPS while switching to Alt-Hold and from there to Loiter. Since upgrading from 4.6.3 to 4.5.5 it seems I get many more cases of flyaways when GPS is enabled in-air. It seems that there are relatively large discrepancies between the velocity during the dead reckoning in climb and the GPS speed at the end of the climb. In my specific application, GPS must be off on the ground and enabled in-air. Does anyone have an idea as to why 4.6.3 would be more sensitive to these discrepancies than 4.5.5? In both there are varying velocities but in 4.6.3 I am having significantly more flyaways where I get big discrepancies eventually between AHR2.Pitch and ATT.Pitch and this causes the copter to go crazy and fly away out of control.
What is the rationale for having GPS disabled while on the ground?
The only ones that come to my mind are direct violations of Ardupilot Code of Conduct or directly related to operations with such violations.