# True airspeed offset in flight **URL:** \ **Category:** PX4 Autopilot\ **Created:** [May 14, 2025, 4:47pm UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562 "2025-05-14T16:47:04Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Alexandre\_Lapadu](https://discuss.px4.io/user_avatar/discuss.px4.io/alexandre_lapadu/32/19397_2.png) [@Alexandre\_Lapadu](https://discuss.px4.io/u/Alexandre_Lapadu)\ **Post date:** [May 14, 2025, 4:47pm UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/1 "2025-05-14T16:47:04Z")
Hi, After searching quite a bit everywhere, I can’t find a way to correct the offset of my Pitot tube in flight. I did perform the ground calibration of the Pitot tube, which went well, but it cannot account for the dynamic offsets that can occur in flight. ![image](https://discuss.px4.io/uploads/default/original/3X/8/3/83c1355dcd777c0c43f8496884be7510075e3ce3.png) ![PXL_20250514_161155608](https://discuss.px4.io/uploads/default/original/3X/e/1/e1295096c9bdf69482c35df3201b2afddf9400eb.jpeg) Can someone help me to find the way to “calibrate” it arround the flight speed ? Thanks in advance ---
**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\ **Post date:** [May 14, 2025, 11:18pm UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/2 "2025-05-14T23:18:21Z")
I don’t think you can easily calibrate in flight, because you’re measuring wind, which is sorta the point. Are you sure you have an offset in all directions consistently? ---
**Author:** ![Alexandre\_Lapadu](https://discuss.px4.io/user_avatar/discuss.px4.io/alexandre_lapadu/32/19397_2.png) [@Alexandre\_Lapadu](https://discuss.px4.io/u/Alexandre_Lapadu)\ **Post date:** [May 15, 2025, 6:54am UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/3 "2025-05-15T06:54:48Z")
> [@JulianOes](#): > > Are you sure you have an offset in all directions consistently? Yes, it was a small flight without wind… ---
**Author:** ![Alexandre\_Lapadu](https://discuss.px4.io/user_avatar/discuss.px4.io/alexandre_lapadu/32/19397_2.png) [@Alexandre\_Lapadu](https://discuss.px4.io/u/Alexandre_Lapadu)\ **Post date:** [May 15, 2025, 7:46am UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/4 "2025-05-15T07:46:00Z")
What’s about the ASPD\_SCALE\_1 parameter ? ---
**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\ **Post date:** [May 18, 2025, 8:41pm UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/5 "2025-05-18T20:41:56Z")
Ok, would be interesting to see your flight log. I can’t really comment without more information. I also don’t even know which airspeed sensor you’re using. ---
**Author:** ![Alexandre\_Lapadu](https://discuss.px4.io/user_avatar/discuss.px4.io/alexandre_lapadu/32/19397_2.png) [@Alexandre\_Lapadu](https://discuss.px4.io/u/Alexandre_Lapadu)\ **Post date:** [May 21, 2025, 3:31pm UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/6 "2025-05-21T15:31:57Z")
Hi everyone, I conducted more flight tests: - **First flight** with the UAV using the same configuration (same issue): ![image](https://discuss.px4.io/uploads/default/original/3X/7/1/71ece8e722c49976f99e84d3a84320b13b0b924f.png) - **Second and third flight** with `ASPD_SCALE_1` set to **0.7** (instead of 1): ![image](https://discuss.px4.io/uploads/default/original/3X/f/9/f94b8d994fc56097250d8079ad01d4a1bd350f2e.jpeg) =\> This time, the ground speed closely matches the airspeed. Note that `ASPD_SCALE_1` can be automatically updated using the `ASPD_SCALE_APPLY` parameter. In my case, I manually set it to **0.7** , but the system is now adjusting it automatically (currently around **0.74** ). I’m not sure why I have such a large offset with my sensor: [Holybro High Precision DroneCAN Airspeed Sensor (DLVR)](https://holybro.com/products/high-precision-dronecan-airspeed-sensor-dlvr?srsltid=AfmBOooih3Z_TYjX9ntLRBiW8tzfHW4F5tO44ehoKfSdt55sKdHJB7TJ) I did a test flight with the [Holybro Digital Airspeed Sensor MS4525DO](https://holybro.com/products/digital-air-speed-sensor-ms4525do?_pos=1&_psq=ms452&_ss=e&_v=1.0), and only observed a small offset. I’ll be receiving two more DLVR sensors soon and will do some cross-checking in flight to see if they exhibit the same offset. Stay tuned! ---
**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\ **Post date:** [May 25, 2025, 9:37pm UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/7 "2025-05-25T21:37:54Z")
Interesting, thanks for sharing the data. Anything out of the ordinary in terms of pitot tube, pressure, temperature? ---
**Author:** ![Alexandre\_Lapadu](https://discuss.px4.io/user_avatar/discuss.px4.io/alexandre_lapadu/32/19397_2.png) [@Alexandre\_Lapadu](https://discuss.px4.io/u/Alexandre_Lapadu)\ **Post date:** [May 26, 2025, 7:23am UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/8 "2025-05-26T07:23:25Z")
You can find the log of the last flight here : [https://review.px4.io/plot\_app?log=680589ab-fdd6-4df4-b6c0-1c40d9c9f2e2](https://review.px4.io/plot_app?log=680589ab-fdd6-4df4-b6c0-1c40d9c9f2e2) ---
**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\ **Post date:** [May 27, 2025, 1:54am UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/9 "2025-05-27T01:54:55Z")
Thanks. I can see how it’s definitely not wind since you’re flying all over the place in all directions, so your finding is valid. I don’t have other data on this sensor, so I’m not sure if it’s specific to your specific sensor or a general issue with this one. @ryanjAA do you have experience with the DLVR-L10D sensor having a large offset like shown above? @Vincentpoont2 FYI ---
**Author:** ![Alexandre\_Lapadu](https://discuss.px4.io/user_avatar/discuss.px4.io/alexandre_lapadu/32/19397_2.png) [@Alexandre\_Lapadu](https://discuss.px4.io/u/Alexandre_Lapadu)\ **Post date:** [May 28, 2025, 7:39am UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/10 "2025-05-28T07:39:39Z")
I made a new flight with a third airspeed sensor : Matek DLVR [https://www.mateksys.com/?portfolio=aspd-dlvr](https://www.mateksys.com/?portfolio=aspd-dlvr) Here you can find the logs of the flight test : [https://review.px4.io/plot\_app?log=214dbc8e-4eab-456c-bdbc-1900188f237b](https://review.px4.io/plot_app?log=214dbc8e-4eab-456c-bdbc-1900188f237b) This one seem to be ok (with arround 7% of offset) ![image](https://discuss.px4.io/uploads/default/original/3X/9/4/948d94bd50c228d2f80a9b673ff2ea28ae4aa473.png) ==\> I’m already waiting for 2 more [Holybro High Precision DroneCAN Airspeed Sensor (DLVR)](https://holybro.com/products/high-precision-dronecan-airspeed-sensor-dlvr?srsltid=AfmBOooih3Z_TYjX9ntLRBiW8tzfHW4F5tO44ehoKfSdt55sKdHJB7TJ) to replace the first one with arround 30% of offset ! ---
**Author:** ![system](https://discuss.px4.io/uploads/default/original/3X/7/3/73ce918bdcd64854de904f0c8d9ab70ca9723f2a.png) [@system](https://discuss.px4.io/u/system)\ **Post date:** [August 26, 2025, 7:40am UTC](https://discuss.px4.io/t/true-airspeed-offset-in-flight/45562/11 "2025-08-26T07:40:29Z")
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