Why does different equipment lead to different positioning accuracy?

I am using dwm1001 to do relevant positioning experiments. I found that the positioning accuracy of different dwm1001 equipment will be very different. I want to know why?

Can you explain what you mean by “different dwm1001 equipment”? Different hardware designs using the same module internally or swapping out theoretically identical modules?

Any material near the antenna will impact its performance and so change the results. You will also see effects caused by the antenna orientation.
If you have identical hardware mounted in the same orientation then the antenna delay calibration accuracy can still impact the accuracy. Temperature will also have an impact.

And that’s assuming you have the same firmware and radio settings for both.

Thank you for your reply. I use four anchor placed into a square area to measure the positioning accuracy of the middle target point, but when I replace two of the four anchor with DWM1001 set as the anchor , of course, the set coordinates are the same, but the positioning accuracy has a deviation of at least 50mm. I want to know why?

What are your anchors before replacing them with DMW1001s?

50mm is not a large difference, that is well within the accuracy I would expect for a 4 anchor system.
Simply rotating the antenna on a system can result in >100mm changes in the measured range. Antenna delay calibration values can also vary by 100mm between units.

While better position accuracies are certainly possible using the DW1000 they generally require more anchors and either better antennas or more complicated code to take antenna orientation into account.

Thank you for your answer. I’m sorry I didn’t reply you in time. I know the reason through your answer. Thanks again.