Title: Distance Measurement Shows Double the Actual Value on nRF52840

RE: Title: Distance Measurement Shows Double the Actual Value on nRF52840

Kazi Afroza Sultana — Thu, 20 Feb 2025 13:02:57 GMT

Hello,

Can you try the other one; zero calibration?

Distance measurement is also affected by the environment; if there is interreference in the environment there is high chance not to get the accurate measurement. How does your testing environment look like?

There is a case (+) nRF Distance Measurement sample - Nordic Q&A - Nordic DevZone - Nordic DevZone which states about adding low pass filter to remove unwanted signal.

This RE: Distance measurement from IQ samples and error estimation describes about Signal to Interference plus Noise Ratio indicators. If these does not seem optimal, we need to change the setup to improve those.

you can also try taking multiple measurements (+) Distance Measurement Accuracy - Nordic Q&A - Nordic DevZone - Nordic DevZone to improve accuracy.

RE: Title: Distance Measurement Shows Double the Actual Value on nRF52840

Usha — Wed, 12 Feb 2025 05:57:08 GMT

"I have already implemented high-precision calculations, but the distance measurement is still inaccurate. Could you suggest specific parameters or settings that might improve accuracy? Also, are there any known issues with MPSL or SoftDevice configurations that could affect the results?"

RE: Title: Distance Measurement Shows Double the Actual Value on nRF52840

Kazi Afroza Sultana — Tue, 11 Feb 2025 13:43:59 GMT

Hello,

Have you looked at this zero calibration https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/nrf_dm/README.html#zero-distance_calibration process which includes an offset.

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.

For more accurate result you can try to do high precision calculation https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/nrf_dm/README.html#high-precision_calculation.