Hi Greg,
precisely there helps a well-calibrated airspeedsensor. You know our tiltrotor VTOL called “Mozart”. Without airspeed sensor, we could fly forward transitions only against the wind. The wind direction does not matter with the sensor.
Here is an example of how exactly arduplane flies at 25 km/h wind and 48 km/h IAS with an airspeed sensor in automode: (pw = skyeye, ground speed and airspeed are displayed in the upper left window)
https://vimeo.com/223652208
I recommend Jordi’s digital sensor with the newer ms5525 pressure sensor. The noise is much lower than the noise of the most used 4525DO:
New Airspeed sensor (MS5525) for ArduPlane 3.8
The analog sensors in my experience on Pixhawk/Pixracer are less precise than the 4525DO. The cable is more susceptible to interference then the same length I2C.
But one thing has to be considered for all digital sensors on one I2C line:
If you have an external compass at the I2C, the data lines may have different voltages. Mixed 5 Volt/3,3 Volt leads to I2C errors.
At our VTOL “Mozart” , we avoided the problem by using no external compass. Otherwise one would have to take an active I2C hub eg http://www.auav.co/product-p/i2c-hub.htm
Regards Rolf