nRF5340 Distance Measurement test

RE: nRF5340 Distance Measurement test

Michal — Wed, 11 Dec 2024 18:27:32 GMT

[quote user="remtec"]Question: Is it possible to constantly set the initiator and reflector?[/quote]

This scanner/advertiser interaction is used as a synchronization point. After a configurable delay, Device A and Device B try to range each other.

If a Device acts as an advertiser in synchronization, it will act as the reflector in the ranging procedure.

If a Device acts as a scanner in synchronization, it will act as the initiator in the ranging procedure.

Best regards,

Michal

RE: nRF5340 Distance Measurement test

remtec — Tue, 10 Dec 2024 08:07:40 GMT

Ok. Maybe I understood the problem.

I was using a nRF52840DK + a custom board based on nRF52840, but with slightly different antennas and the measurement changes depending on who is the initiator and who is the reflector.

With identical cards the uncertainty is not so evident!

Question: Is it possible to constantly set the initiator and reflector?

RE: nRF5340 Distance Measurement test

remtec — Fri, 29 Nov 2024 14:17:59 GMT

These 'disturbances' seem to be present at small distances, under 10 meters.
I'm doing tests around 20 meters and the results seem much more stable.

RE: nRF5340 Distance Measurement test

remtec — Fri, 29 Nov 2024 09:43:01 GMT

No. In that test the two boards remained stationary at 8 meters! But not the measurement!
Today I noticed that the measurement seems to be significantly influenced by the proximity of the human body to the boards, even if these have their own small antenna on the PCB: I thought that this type of measurement was not as affected as the RSSI.
What do you think about this?

RE: nRF5340 Distance Measurement test

Michal — Thu, 28 Nov 2024 22:53:13 GMT

Ah, okay, that makes the issue worse, I agree.

So you are continuously moving the devices apart and this is the result, is that correct?

RE: nRF5340 Distance Measurement test

remtec — Thu, 28 Nov 2024 10:27:14 GMT

Hi Michal.
On the X axis are the seconds, on the Y axis are the meters.
These drops fall randomly: if it's 1 or 2 I can filter them, but if it stays for 10-20 seconds I can't eliminate them.
I also tried changing the timeslots parameters but it doesn't change.

RE: nRF5340 Distance Measurement test

Michal — Wed, 27 Nov 2024 21:07:08 GMT

Hello,

How often are those drops happening?

What unit are you using for the x-axis?

Best regards,

Michal

RE: nRF5340 Distance Measurement test

remtec — Tue, 26 Nov 2024 09:14:42 GMT

Sorry for the little info: the upper line is with phase_slope method and the lower is ifft method. The boards have always been about 8 meters away.