Multiple Height References

Good afternoon,

I was wondering if there was a way to use multiple references for height estimation.

The drone I am using has a tracking camera and can fly in VIO but also has a GPS. The problem with flying in VIO outdoors is that you are limited by height.

I want to ideally be able to fly indoors with VIO when there’s no GPS signal, and use vision as the height reference, and then fly from indoors to outdoors and have it switch to using GPS as the main height reference when there are enough SATS / strong enough GPS signal.

Is there a way to do this in PX4? I notice that EKF2_HGT_REF only allows for one option, so my initial thoughts are that it would not be doable without modifications to PX4 itself.

My worries about using barometric pressure for height estimation are that the pressure would change when going from indoors to outdoors, so it might mess with the height estimation.

Is there a way to use vision as the default height reference unless GPS signal is strong enough? Are multiple height references possible?

Answering my own question, but I set EKF2_HGT_REF to GPS and EKF2_BARO_CTRL to disabled and it appears to be flying in VIO when there’s no GPS signal. Nice!

EKF2_HGT_REF is just the primary height reference I think

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