Disable the head tracking on OVRCameraRig for Oculus Go

I am trying  to replace the head tracking device on the  Oculus Go with my own tracking device. I build a prefabs that attached  to the OVRCameraRig, and was able to make Oculus Go to follow  the movement with my tracking device. The problem is that, now the build in tracker and my own track are both effective.  If I rotate 45 degree, the camera will think I moved 90 degree, 45 degrees from the  build in tracker and 45 degrees from my tracker. Is there any way I could disable the build-in tracker?

I search for previous threads on in this forum and in Unity forum. The latest answer  was two years ago, which are not applicable for the new environment.  

I am currently using Unity 2018.2.11f1, and oculus integration package 1.30.1


Thanks,

Hao