Sensirion SDP3x incorrect meassurements

Hello everyone,

I have been using the SDP3x sensor for the last months, but when I compare the airspeed with the speed computed gps I always obtain lower values for the first one (with wind or without wind). I’ve been using also different SDP3x sensors and always the same problems.

The pitot is installed in the nose of the aircraft as it comes. The only modification is that the I2C cable that is used is 90 cm long approximately.

Despite that in the specs it is indicated that no calibration is required, I think that the ARSPD_RATIO must be modified. I would appreciate any help on this matter.


Hello and welcome to the community.

Assuming you are using Ardupilot, did you check this documentation :

Let us know if your speed values has been resolved using ARSPD_AUTOCAL = 1


Hello Paul,

Yes I’m using ardupilot. I will try the auto-calibration as you suggest.



we experience the same issue, the average groundspeed is always about 2m/s higher than the average airspeed.

We’re running PX4 v1.9. I tried to calibrate with QGC, but it throws an error, “Check your wiring before trying again”. But the wiring can’t be the problem, since the sensor is functional apart from the offset.