Altitude sinking at hover

Due to weather, I haven’t been able to perform a full autotune yet but before I do, I wanted to see if I I could get some input on this odd altitude sinking issue. I’ve attached a few logs below as I’m not sure what to look at for this issue.

At hover, the quad will sink 3-5 feet and eventually slowly recover seemingly to a higher altitude than originally commanded. The baros are contained within the body and not open to the outside air so prop wash shouldn’t be the issue. The FC is a Cube Orange+ for reference.

https://drive.google.com/file/d/15G3mxsnC6SIhxFlHxk4Pu-BwZSQxhFMs/view?usp=share_link

Attempted autotune which I ended early due to a crowded flying field and unease about altitude issue.

https://drive.google.com/file/d/19WjGz3pMqF0PJG8GNZ4GGFg4Z1jswMuf/view?usp=sharing

Improve your GPS reception, improve vibrations and improve baro isolation

VibeX below 8.5, VibeY below 10 except for a single peak of 14, VibeX below 12.5 all on average not terrible. Yes I can improve that but I’ve seen worse in builds without this issue.

Baros/FC are/is fully enclosed inside the body. Not sure how much more they can be isolated.

HDOP is .66 currently w/15 sats in view. .7 is about as good as it gets around here. The below images are all I’ve got in my area.


Was there something specific that popped out or was that just general advise?

That was general advice.

The sat count is only half the story. Is your update rate consistently above 5Hz? If not reduce the number of GNSS constellations.

I’ll try both GPS & GLO and GPS & GAL and see which of the combo’s works best. Is there a place in the log that shows what the refresh rate actually is during a flight or does ardupilot just take up to what’s set as the max? Should note this is a here3+ with an update rate of 8 hz. Ardupilot is set as default 5 hz.

Edit: Found it. (GPA.Delta) Going through the logs over the past few days, it looks pretty consistent at 200ms with brief dips to 199ms & a few spikes to 202.5ms. So to answer the question, no the rate is not consistently above 5 hz.