Values decrease over time


I am using the DWM1000 module, and for some reason as time goes on the ranges between an anchor and tag decrease. The distance between the two stay the same however the range is decreasing. Can anyone provide with possible reasons as to why this is happening? Nothing else besides TWR is being performed and there is not changes to the enviroment

Are the nodes calibrated ,crystal trimmed. and how are nodes powered (battery, usb or power supply) ?
What SW API is used? Are you using examples 5a/5b or 6a/6b, if not please use these example codes.

The nodes are callibrated.

The crystals isn’t trimmed as I did not fully understand it.

The nodes are powered by batteries.

I am using my own code not the example code.

You have not specified the time over which it happens)

On the top of my head the distance is the subject to change 2.3mm per degree centigrade (the curve is linear).

If to keep the TWR Responder in Always On RX, then your temperature would stabilize in ~30 seconds.

The graph below shows the values. The x-axis is just the number of ranges. The y-axis is the range. The plot is run over 10minutes. The distance between the anchor and tag is 1m

I suggest you use examples 5a/5b or 6a/6b and try with these.
Also maybe try a different power source if possible, eg usb or wall charger… And could you send a picture of your setup?


I am sorry, but your graph does not look as the ranges. This is something strange, please think about what are you drawing.