Mixed-Reality Tracking Drift Issue

Question

I’m developing a mixed-reality application in Unity 6 that demands highly precise tracking. The goal is to position virtual objects at specific world locations and have them remain fixed reliably. My current approach involves:

• Creating three spatial anchors.
• Calculating the middle point between these anchors.
• Instantiating a small cube at that midpoint, with all virtual objects positioned relative to this cube.

Despite several months of testing, I’ve noticed a drift of a few centimeters, particularly when moving further away from the anchors and then returning. I’m looking for suggestions on how to address this issue. Specifically:

• Are there alternative approaches with spatial anchors that could reduce this drift?
• Is there any proven method to recalibrate or smooth out the drift over time?
• Or, does anyone know of a supported physical tracker that could provide reliable positional data to enhance precision in this setup?

I have tried to find some insights, particularly with an external tracker in the face of the VIVE Ultimate Trackers, however, it seems that all of the trackers I find are not supported for Quest 3 and only for PC VR, to track body-movements.

Any insights, experiences, or recommendations would be greatly appreciated. Thanks in advance for your help!