I have been using the dw3000 evaluation board to perform ranging with the SS-TWR.
I have conducted ranging at 5m, 10m, 15m, and 20m, and have confirmed that ranging is possible with an error of 5cm or less in all cases.
However, when measuring at 20m, we found that the error suddenly increased depending on the location. The location where the error increased was about 5 cm wide, and the maximum error was about 20 cm.
We have already confirmed that there are no obstacles or other objects blocking the projectile line.
I would like to know the possible reason why this occurs.
What we see that when the TN/AN is low like 1m - 1.5m at some distance (like 20m) you might get much worse distance measurements than usual. But when you pull them up like in 2m then all readings are fine. This mostly caused by reflections and for UWB this sometime works in the most weird way - this is one of the reason why AN should be placed high (also you have much less obstacles between AN and TN when AN are placed at some reasonable height.