From time to time while my P4P is hovering at about 15'-25' above ground with no wind, it will rise and descend 3'-4' or so. It does it somewhat slow and not erratic. I can't really tell if there is change in Tom's from the props or not. It just seems to be unstable like it can't get a good elevation lock. I have good gps signal.  Any ideas or suggestions what is causing this? Is this something a IMU calibration would correct? I've never done one of these and I've had the Phantom for about a year and a half. I get worried this thing is going to want to do it's rise and fall act at a bad time, like when I'm near a tree or something else I don't want it to climb into. Any help would be appreciated?

Try climbing higher to get out of the VPS range and see how it does. In any event, that is pretty stable anyway, it is only as good as the barometer altimeter.

Geebax Posted at 2018-5-20 21:30
Try climbing higher to get out of the VPS range and see how it does. In any event, that is pretty stable anyway, it is only as good as the barometer altimeter.

It does it even at higher altitudes, I guess I just notice more when it's lower because I can have a direct line of reference. It hasn't always done this, it's just been over the last month or maybe two that it's started doing it. It used to be absolutely rock solid in anything short of 20mph winds. That's why I was thinking some sort of calibration was needed.

Do the following in the order listed, then test fly again:

1) IMU calibration on a level surface
2) Compass calibration in wide open space

Also make sure you have solid GPS signal, and that you are in P-mode.

I would agree with rent but i would only do an IMU calibration first and test it  , i'm not sure a compass calibration will stop the rise and fall ?   also you can turn off the VPS  if you want to test it below 20mtrs

rent Posted at 2018-5-21 09:44
Do the following in the order listed, then test fly again:

1) IMU calibration on a level surface

Ok, I will give this a go and see what I can come up with. Thanks for the help.

DEUCEDOG Posted at 2018-5-21 09:57
I would agree with rent but i would only do an IMU calibration first and test it  , i'm not sure a compass calibration will stop the rise and fall ?   also you can turn off the VPS  if you want to test it below 20mtrs

I agree, one thing at a time to isolate possible issues, thanks.

yep Just work thru one thing and test , if your unstable hover is constant it should  be easy to isolate , let us know how you get on?

Hi there, may I know what's the current aircraft and controller firmware? Make sure both have been updated to the latest version and then do IMU calibration to check the exact status.

Got same problem started within the last month I guess.
It makes it a bit difficult to shoot pictures.
I’ll also try make the IMU calibration and see if it makes any difference.
By the way.... this problem started along with unstable app chrashing more offen than else. (+controller)

This seems to be normal on the P4P. Mine has always not been able to hold an altitude like this, slowly drifting up and down a few feet. Most videos I've seen of the P4P doing hover tests for endurance, etc., show it doing this too.

And no, IMU and compass calibrations won't help. It's just how the machine is, for whatever it is that's wrong with it.

The mavic pro, OTOH, is rock steady and doesn't drift up and down. Go figure. I wouldn't consider it anything to worry about unless it's really really bad...

i am on the latest fw and do not see this issue so far...

+2 for FarmerMac and luciens
After some discussion from an other thread my conclusion is that the baro-/alti-meter used in the P4P or perhaps some of them is just not up to the task of being placed in a drone.
On the other hand, the one i had before it got replaced for among other this particular issue was working fine before v.1.4.602, so perhaps something has been messed up in FW since that version.

luciens Posted at 2018-5-22 04:06
This seems to be normal on the P4P. Mine has always not been able to hold an altitude like this, slowly drifting up and down a few feet. Most videos I've seen of the P4P doing hover tests for endurance, etc., show it doing this too.

And no, IMU and compass calibrations won't help. It's just how the machine is, for whatever it is that's wrong with it.

I agree, the Mavic is pretty solid. I just don't remember my phantom being like this all the time. I get worried when I'm near some trees doing photos,  and I've given myself plenty of space, and it's going to start rising on me and get into a branch or something.

14jnewmy14 Posted at 2018-5-22 08:04
I agree, the Mavic is pretty solid. I just don't remember my phantom being like this all the time. I get worried when I'm near some trees doing photos,  and I've given myself plenty of space, and it's going to start rising on me and get into a branch or something.

It comes and goes; my P4P is stable sometimes too, but it eventually starts doing the up/down drifting again. I can't isolate when it does that, it just seems to be random.

I don't think there's anything that can be done about it unfortunately....