What's the different between ARSPD_ENABLE and ARSPD_USE

there are two parameters(ARSPD_ENABLE and ARSPD_USE ) I am not sure how to set! If my aircraft do’nt have a airspeed sensor.
if no airspeed sensor,both of them set to zero?
I had thought ARSPD_ENABLE=ARSPD_USE . What is the different effect between the two parameters ,I don’t get it .

This may help:

plane.ardupilot.com/wiki/fixed-w … eed_sensor

ARSPD_ENABLE - is used to turn on the air speed sensor and it then starts producing data. However, it won’t be used in flight control. We do this so we can see what the air speed sensor is doing and whether we think its correct BEFORE we hand over control of the airframe to it.

ARSPD_USE - This means take the airspeed data and use it for flight control.

Thanks, Grant.

thank you for your help! Just One More Question
if I set both of them to zero,APM:Plane would use synthetic airspeed value for flight control,is that correct?


I have a new airplane that I will be flying and calibrating when the weather gets better. My question is do I have to have both ENABLE and USE turned on to do an airspeed calibration or can I just have ENABLE on to calibrate the airspeed sensor?


You don’t need ARSPD_USE=1 to calibrate it. I’ve added a note on that to the docs:
plane.ardupilot.com/wiki/calibra … ed-sensor/