Unstable MS5607 Baro Issue

Hi ,
I have a Pixhawk 2.4.8 (knockoff) .
The issue here is that the reported altitude is going all over the place even when it’s kept on the bench.

After many hours of searching here, on rcgroups, and Github I couldn’t find a solution but found out that this board has a MS5607 baro instead of the traditional MS5611 but in the Hardware Id tab of mission planner it is being recognized as MS6511 instead of the MS5607. , so I wanted to ask is there any way to select the correct driver manually?

I see this issue was reported to Ardupilot long ago but I don’t know whether this was resolved or not - Baro: search for MS5607 in Pixhawk · Issue #8258 · ArduPilot/ardupilot · GitHub

I have tried installing older firmwares all the way back to 3.2xx but it didn’t help either.

Some points I would like to share :

Even on PX4 this issue is there but when I change the SENS_BARO_QNH parameter it starts working accurately but I can’t find any similar parameter in ArduPilot .

The pressure reported by the sensor is around 500hpa (which is not normal for MS5611 but it is for MS5607 as it has half the resolution ) .

Any suggestions/help are welcomed :slightly_smiling_face:

By going through the PX4 documentation, I found that SENS_BARO_QNH has a default value set to 1013.25 hPa (or 101325 Pa), which is the pressure at 0 MSL. Basically, I believe this parameter is used to calibrate the barometer with the atmospheric pressure at your location (correct me if I am wrong).
So, going ahead, in ArduPilot, there is a parameter called BAROx_GND_PRESS (replace x by 1, 2 or 3 etc.). Maybe that is the parameter you are looking for?