Inquiry about Distance Measurement Using Two E73-2G4M08S1C nRF52840 Modules

[Usha]

Dear Nordic Support Team,

I am working on a project to measure distance using two E73-2G4M08S1C nRF52840 modules. I would like your guidance on the best approach for implementing this functionality. Specifically, I am interested in:

1. Recommended libraries or examples from the nRF Connect SDK for distance measurement.
2. Suitable protocols (e.g., BLE, AoA, or RSSI-based ranging) for achieving accurate results.
3. Any hardware configurations or settings that could improve measurement accuracy.

Thank you for your support.

Best regards,

[Elfving]

Hi!

That sounds like a plan! You can then either focus on distance measurements, or direction finding. 

For distance measurement we offer the proprietary nordic distance toolbox (which we also provide along with some samples if you want to try it out), as well as the new BLE technology channel sounding (try it out yourself here), which we support in the newest NCS versions. They both depend a bit on the same technology.

We also support direction finding, though we do not have valid QDIDs for the locator in the newest NCS versions. For more about the technology behind DF, have a look at our white paper on this here. 

Regarding the differences and what would be the best option there is a lot to consider, and too much for me to type in here, though let me just mention a few things:

One difference between these options is that channel sounding for the time being requires a connection. Direction finding and NDT does not. So for indoor positioning of multiple items, direction finding is often considered. One issue with DF is that it requires some work on an angle algorithm (eg. this) in order to get good results, and we do not provide these. It also requires some extra hardware, like antenna matrices for the locator. The NDT provides a few good working algorithms, while with channel sounding you would typically create your own as well, however we do provide one.

I think this previous webinar on the NDT describes how the NDT works rather well, and also works as a good introduction to the technology (eg. why you should not use RSSI for distance measurements, etc.). Have a look at that.

Thanks for the question, and let us know if there is anything else.

Regards,

Elfving

[Usha]

Subject: What Hardware Can Be Used to Measure BLE Distance in nRF?

Hello,

I'm working on a project involving BLE distance measurement with nRF52840 and nRF52840 chips, and I am looking for suitable hardware options to accurately measure the distance between BLE devices.

Can you recommend any specific hardware or tools compatible with these chips that can assist in measuring BLE signal strength or distance? Any advice on additional sensors or modules would be greatly appreciated.

Thank you!

[Elfving]

Usha said:

nRF52840

Ah I see.

Essentially all nRF52s support NDT, and that includes nRF52840 For Channel sounding I believe we currently only have official support for nRF54L.

So considering that you want to use nRF52840 for this then the nordic distance toolbox sounds like the way to go. 

Usha said:

Can you recommend any specific hardware or tools compatible with these chips that can assist in measuring BLE signal strength or distance? Any advice on additional sensors or modules would be greatly appreciated.

Not really, as the protocol doesn't use it. You could allways try to add something propriatary on top of NDT, and try to merge the two with a Kalman filter to get an even better result, though additional hardware is not something that NDT requires per se. And NDT unfortunately can't take advantage of FEMs, as they would modify the delay and CTEs.

Regards,

Elfving