How to cancel drift in AR

Hello !

I am looking to place large objects (even very very large) in augmented reality. But I have a big problem with model sliding once it is instantiate. Where does this drift come from ? Is this a problem with the interpretation of the phone's sensors or the phone itself ? And is there a way to fix this drift ? I seen videos made in Unity with objects the size of a small building perfectly stable ... I am jealous :( Thanks for reading my wonderful google english ! ;)