The SYNC pin has to be connected to the MCU (the same MCU pin for both DW1000).
Asserting SYNC pin high resets the internal counters and state machines to the same state so later after receiving a frame from the Tag MCU can extract additional information from CIR buffer from both DW1000 to calculate the phase difference of arrival (timestamp accuracy is not enough).
If you check the DWM1002 Node schematics, you’ll see the SYNC circuit - it’s rather complicated to meet the required specifications (and not all of them to be honest).
Actually you can even toggle the pin simply by the MCU pin, just need to carry out some additional checks.
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I also spotted the ceramic antenna you are using. Despite it is widely used in UWB applications I do not recommend it for any PDoA project for a simple reason - the polarization of this antenna is far from circular, which is requred for these types of applications.
With say linear polarized antrennae for the Node and the Tag the resulting phase difference will be dependant on the mutual orientation of the devices, not only the Tag’s position wrt the Node.
The antennae used in Beta PDoA Kit are circular- and cross-polarized.