Since two week our Phantom 2 v+ isnt´very stable while hovering. It floats up to 2 m in every direction. Even when there are 9 Sats available.

Check your gain settings in the assistant software,  read the manual or YouTube a walkthrough....

watch the basic videos about the phantom series. what is the software saying, everything ok? calibrate your phantom

In addition to what others have said, you may want to advanced calibrate IMU.

That said, it could bee satellite error.  Moving around within a 2 meter error is within satellite error and if you have trees or other obstacles around it can wonder a bit.  If you are low to the ground, it will wonder.

I agree it sounds like calibration but it could just be the location.

Check that the props aren't damaged as well.

kenargo Posted at 2014-11-28 00:29
In addition to what others have said, you may want to advanced calibrate IMU.

That said, it could b ...

Just do advance calibration. GO to PC assistant software under "tools" click "Advanced" then click "Advance Cali" make sure phantom is level and away from any metal don't move or unplug until finished it may take a while just be patient. Make sure cable is connected to your Phantom and the computer also your transmitter is  turned ON. Good luck and Happy Thanksgiving!!!

Yes calibrate IMU and check Gain setting in Ass
And Besides these you need to calibrate the Compass before take off!
Happy Thanksgiving!