Dwm1000 module timestamp problem


I am developing a project using dwm1000. In my project, I used two dwm1000 circuits as an anchor.

I used a Sniffer device containing a dwm1000 and a tag device containing a dwm1000. The Sniffer device is equidistant from two anchors. My tag device only broadcasts once every second.

Anchor devices receive the broadcast from the tag and record the time they receive the broadcast. Then the anchors transmit the identity of the message they receive to the Sniffer at certain intervals.

After this operation, the anchors send also txtimestamp-rxtimestamp values (Antx_rx1, Antx_rx2) to the Sniffer device. Thus the time difference in the Sniffer anchor is also sent.

The Sniffer records the timestamp values (Snrx1, Snrx2) of the first incoming messages at the moment they arrive.

After second messages came, I calculated the tdiff value using the formula tdiff = Snrx2-Snrx1-Antx_rx2 + Antx_rx1 in Sniffer.

In my calculations, the tdiff value measured when the tag is next to the anchor number 1 and the tdiff value measured when the tag is next to the anchor number 2 should be the same.

However, in my measurements, there are significant differences in the constantly measured tdiff values. When I changed the order in which the two anchors sent data to the Sniffer to compensate for this difference, the result did not change. When I changed the dwm modules of the two anchors, the results obtained were the negative equivalents of first values I had obtained. The idea that I took as a basis for doing these operations in this project was that frequencies of all dwm1000 modules were the same. So, how can I solve this problem?

Yours truly

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You need to compensate for the clocks on anchor 1 and the clock on anchor 2 running at different rates.
Measure the time period between two transmissions from the tag on both anchors, any difference between the measured period on each of the anchors will be due to their clocks being different, you can then use this value to compensate for the errors.

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