GPS Barometer Airtightness Issue

General
1

Hi everyone, I’d like to ask a question about the GPS barometer. How much compression should be applied to the foam over the barometer to ensure that the installation is considered acceptable?

For example, when the GPS module is installed on a multirotor or fixed-wing aircraft, what should the barometer data typically look like during operation? What kind of data trend or curve would indicate that the barometer and foam installation are working properly?

I’d appreciate any advice or reference data. Thank you!

2

Use search here for “barometer foam”

3

Make sure You used open cell foam

4

The answer is not airtight. Use just enough open cell foam just to keep wind effects from disturbing the sensor.

There is no way to show you a proper curve. The reported baro altitude should follow actual altitude as visually observed or measured via other means.

5

Also if you have the electronics in a case or protective cover/monocoque body no cell foam is needed.

6

GPS LOG

This is the flight log from a fixed-wing aircraft equipped with the GPS module I am currently testing. I think the barometer performance of the GPS module is quite good, but I am not completely sure. I would appreciate hearing your opinions. Thank you.

Flight Controller: V6X
Firmware Version: APM-Plane 4.5.7
GPS Module: M9N
Aircraft Type: Fixed-wing aircraft, approximately 1.5 m wingspan

7

I am simply comparing the GPS barometer with the onboard barometer and observing whether their relative relationship remains consistent under all conditions. If it does not, I would consider that an indication that the GPS barometer housing is being affected by airflow or pressure suction.

8

I noticed that almost all commercial GPS modules have a piece of breathable foam covering the barometer, so I tried to follow the same design.