Drone drift using vicon system

Hi everyone,
I have some trouble using vicon system as external GPS.
I have followed the instruction here (https://ardupilot.org/copter/docs/common-vicon-for-nongps-navigation.html). The problem is that the drone drifted while in PosHold mode. I fixed this by adding a optical flow, but I still really want to flight without optical flow. Anyone know about this issue? Do I need to do other things not mentioned in the instruction?

What hardware? what FW versions? Can you post a dataflash log showing the drift?

My hardware is CUAV5+ using copter 4.05. Sorry for now I don’t have the drift data log but I will try to provide it asap.
Have you successful in using vicon as mav gps?

Take a look at:

and help us out.

1 Like

Sorry for a dumb question, but do you use vicon as gps_type=14 (mav gps)?

I don’t. But there are others that do.

Thanks! I will check my drone as yours suggestions

Today I have made some tests, here is the 1 log file

I observed that: In the Position control data, the PX seem to not oscillate much and perform a good poshold but the data in VISP is difference, do you know about this problem? Is that the problem come from vicon setting or it come from my control param?