Title: Best Method for Accurate BLE Distance Measurement Between Two Devices

RE: Title: Best Method for Accurate BLE Distance Measurement Between Two Devices

Simonr — Fri, 28 Feb 2025 10:30:10 GMT

The documentation is rather brief, but it is basiacally explaining what's necessary. You need to compensate the zero-calibration offset and by performing a manually calibration. To determine the offset, place the devices at a known reference distance (we recommend 60cm) from antenna to antenna. Then collect a batch of measurement data. The difference between the average measurement and the actual distance can then be used as an offset. Whether you implement this offset to be deducted/added in the calculation on either of the devices is entirely up to you.

Best regards,

Simon

RE: Title: Best Method for Accurate BLE Distance Measurement Between Two Devices

Usha — Thu, 27 Feb 2025 09:49:41 GMT

"I haven't performed the zero-distance calibration yet, and I'm not entirely sure what it entails. Could you please clarify what steps are involved in the zero-distance calibration process?"

RE: Title: Best Method for Accurate BLE Distance Measurement Between Two Devices

Simonr — Thu, 27 Feb 2025 09:24:00 GMT

Have you done the Zero-distance calibration that's mentioned and recommended in the sample documentation as well? https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/nrf_dm/README.html#zero-distance_calibration

Best regards,

Simon

RE: Title: Best Method for Accurate BLE Distance Measurement Between Two Devices

Usha — Thu, 27 Feb 2025 09:13:55 GMT

"I have enabled CONFIG_DM_HIGH_PRECISION_CALC in the nRF Distance Measurement sample, but the measured distance is not accurate. The actual distance is 1 meter, but the readings I get are around 1.70 or 2.05 meters. Is there any additional calibration or configuration needed to improve accuracy?"

RE: Title: Best Method for Accurate BLE Distance Measurement Between Two Devices

Simonr — Thu, 27 Feb 2025 08:43:00 GMT

We're getting started with development of the Bluetooth Channel Sounding solution now, and that will be the best way to do BLE based distance measurement going forward. As of yet it's experimental, but more SW support is coming. Note that only the nRF54L15 supports Bluetooth Channel sounding as of yet. For nRF52/53 series the Distance measurement sample can be used.
The Distance Measurement subsystem and service is available from the Distance Measurement sample linked to.
Enabling CONFIG_DM_HIGH_PRECISION_CALC in the nRF Distance Measurement sample will impact the MCPD ranging mode to provide a more high-precision ranging result. However the best result will be combining RTT and MCPD and find a best estimate from the two.
Not for the Distance Measurement sample, but for Channel sounding, an option is to use antenna arrays to get a more precise ranging with multiple antenna points.

Best regards,

Simon