Disable barometer in Alt hold mode

We have a pixhawk cube orange FC which has a terabee collision avoidance system operating. This is for a underground tunnel shaft inspection and therefore we don’t have GPS. For the avoidance system to work we have to fly in Alt hold mode. We have a downward facing rangefinder thats good to detect up to 60 metres. The shaft is 90 meters vertically and therefore after 60 meters, the pixhawk then takes readings from the barometer. The error of drift when flying under barometer readings is too great that we need to disable the use of the barometer. If this is not possible, it means we will have to fly in stabilse mode which isn’t really realistic within a 3 meter diameter shaft as this also disables the lateral avoidance system.
Thanks!

I think that for this specific purpose you would have to change the EKF3 height source to rangefinder (and install a rangefinder upwards or backwards).

Maybe @rmackay9 can give you more advice about it.

Thanks @BrunoBagarini

I believed that when the rangefinder becomes out of range and not detecting then the pixhawk then reverts back to using the barometer?

Cheers

Not 100% sure about it. Maybe there is some kind of parameter to setup the secondary source, but really don’t know, sorry.