Units for SCALED_PRESSURE

[gcelec (Geoff Cook - SeaView Systems)]

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)

[tony-white]

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

[EliotBR (Eliot)]

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.

That said,

@EliotBR

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:

@EliotBR

The compass and depth data can be retrieved from VFR_HUD , tilt and pitch are available in ATTITUDE , and temperature from an external pressure sensor like our Bar30 or Bar100 can be retrieved from SCALED_PRESSURE2 , while temperature from a dedicated temperature sensor like our Celsius can be retrieved from SCALED_PRESSURE3.