When testing different PDOA boards, when the tag is 2 meters away from the AOA board, and it is at the center of the AOA antenna, the angle obtained by AOA may be 0 degrees, -20 degrees, or 30 degrees. How to ensure consistency? Is it possible by improving some components? Or can it only be corrected at the factory?
If you want to remove this angle offset each node should be calibrated - there is Calibrate button in PC GUI application.
20 degrees of angle means roughly 20ps of ToF difference.
This offset spread is mainly due to pcb and IC process variation as well as component variation such as DC blocking caps or baluns and it is practically unavoidable.