# Units for SCALED\_PRESSURE

**URL:** <https://discuss.bluerobotics.com/t/units-for-scaled-pressure/17420>\
**Category:** ArduSub\
**Created:** [July 12, 2024, 7:46pm UTC](https://discuss.bluerobotics.com/t/units-for-scaled-pressure/17420 "2024-07-12T19:46:07Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![gcelec](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/gcelec/32/2038_2.png) [@gcelec](https://discuss.bluerobotics.com/u/gcelec)\
**Post date:** [July 12, 2024, 7:46pm UTC](https://discuss.bluerobotics.com/t/units-for-scaled-pressure/17420/1 "2024-07-12T19:46:07Z")

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I’m exporting some mavlink data to our survey software and I’d like to include depth. What are the units for SCALED\_PRESSURE? (press\_abs": 989.4674682617188)

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**Author:** ![tony-white](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/tony-white/32/18385_2.png) [@tony-white](https://discuss.bluerobotics.com/u/tony-white)\
**Post date:** [July 13, 2024, 7:07am UTC](https://discuss.bluerobotics.com/t/units-for-scaled-pressure/17420/2 "2024-07-13T07:07:22Z")

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Hi @gcelec -  
I believe the units are mbar, that depth would correspond to about 9.86m?

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**Author:** ![EliotBR](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/eliotbr/32/6937_2.png) [@EliotBR](https://discuss.bluerobotics.com/u/EliotBR)\
**Post date:** [August 1, 2024, 5:23am UTC](https://discuss.bluerobotics.com/t/units-for-scaled-pressure/17420/3 "2024-08-01T05:23:50Z")

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Hi @gcelec,

> [@gcelec](#):
>
> I’m exporting some mavlink data to our survey software and I’d like to include depth.

We’d typically recommend getting the depth from `VFR_HUD.alt`, since that’s the autopilot’s depth estimate, and makes use of the water density specified in the autopilot’s parameters.

> [@gcelec](#):
>
> What are the units for SCALED\_PRESSURE?

They’re specified [in the message definition](http://mavlink.io/en/messages/common.html#SCALED_PRESSURE).

That said,

> [@Ongoing DVL-A50 issues](https://discuss.bluerobotics.com/t/ongoing-dvl-a50-issues/11419/36):
>
> `SCALED_PRESSURE` is used for the pressure sensor onboard the autopilot, so is a pressure reading from inside your enclosure. That’s generally more useful for aerial vehicles (e.g. for determining altitude of a drone), but can also help determine if there’s an excessive pressure in an enclosure.
> 
> The Bar30 measurements get reported via `SCALED_PRESSURE2`.

For more general reference:

> [@Extract data from Navigator Flight Controller in real time](https://discuss.bluerobotics.com/t/extract-data-from-navigator-flight-controller-in-real-time/14076/2):
>
> The compass and depth data can be retrieved from [`VFR_HUD`](http://mavlink.io/en/messages/common.html#VFR_HUD), tilt and pitch are available in [`ATTITUDE`](http://mavlink.io/en/messages/common.html#ATTITUDE), and temperature from an external pressure sensor like our [Bar30](https://bluerobotics.com/store/sensors-sonars-cameras/sensors/bar30-sensor-r1/) or [Bar100](https://bluerobotics.com/store/sensors-sonars-cameras/sensors/bar100-sensor-r2-rp/) can be retrieved from [`SCALED_PRESSURE2`](http://mavlink.io/en/messages/common.html#SCALED_PRESSURE2), while temperature from a dedicated temperature sensor like our [Celsius](https://bluerobotics.com/store/sensors-sonars-cameras/sensors/celsius-sensor-r1/) can be retrieved from `SCALED_PRESSURE3`.