Thanks for the password. I missed it on your first post. Using the internal compass seems to work fine on the Pixhawk. I'll have to check what my M8N GPS uses for compass I2C levels but using the internal Pixhawk compass is an elegant solution. I have tested this before on a copter and use the internal compass on the Antenna Tracker. I see that the Pixhawk I2C port supplies +5v and Gnd but uses pull-up resistors to 3.3v.
Looking at your video and your graph, I see the GPS speed changing with upwind and downwind passes while the actual airspeed is quite consistent. My assumption is that when an airspeed sensor is active on the Pixhawk, the Q_ASSIST_SPEED reads the airspeed sensor and not the GPS speed. Does this sound correct?
I am learning much about the airspeed sensor and really enjoy this part of the hobby. Below is a copy from charles_c from an older post. I have added what I have learned.
- Better endurance, more flight out of your batteries
- Better turns and altitude control in auto-throttle modes
- Makes auto landings much easier
- Reduces possibility of stall
- Helps in windy conditions, slow flight, and autonomous landings
- One more sensor to tune
- One more part to break
- Added cost
- May conflict with external compass I2C (use internal compass)