How to calibrate channel sounding sample code to work with Holyiot nRF54L DK Development Board?

[rena2019]

I setup 2 Holyiot nRF54L DK Development Boards with the channel sounding sample code from NCS 3.1.1 samples/bluetooth/channel_sounding_ras_initiator (initiator and reflector) and made the follwoing measurement:

distance 0.3m     ifft: 0.65
distance 0.55m   ifft: 1.36

seems that the measured distance always correspond to about twice the actual amount? Is it due to a different antenne on the Holyiot board? How to calibrate?

[SwRa]

Hi Rena,

The measured distance being twice the actual distance is likely due to an offset in the distance measurement, which is a known behavior when using Bluetooth Channel Sounding on Nordic devices. This offset can be caused by differences in radio circuit design, antenna type, or PCB layout—so using a different antenna (such as on the Holyiot board) can indeed affect the results.

To determine the offset value, place the devices at a reference distance of 60 cm from each other and collect a batch of measurement data. The difference between the average measurement value and the actual distance can be used as an estimate of the offset.

See here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/nrf_dm/README.html#zero-distance_calibration 

Best Regards,

Swathy

[rena2019]

Thanks for the answer but the mentioned sample samples/bluetooth/nrf_dm is only supported for the following boards:
nrf5340dk/nrf5340/cpuapp
nrf52dk/nrf52832
nrf52840dk/nrf52840
nrf52833dk/nrf52833