Combining GNSS and CoAP client in nRF Connect SDK — GNSS fix not read, CoAP request not sent

[Arun538]

Hi Nordic team,

I’m working on an nRF9151 DK with nRF Connect SDK v3.0.0.
My goal is to send GNSS latitude/longitude data to a CoAP server.

• The GNSS sample works fine → I get correct coordinates.

• The CoAP client sample works fine → I can send POST requests and get responses from my server.

• But when I combine both in one project, I get no GNSS fix and no CoAP messages are sent.

I only see: 

<inf> coap_client_sample: Starting GNSS + CoAP client
<inf> coap_client_sample: Bringing network interface up
<inf> coap_client_sample: Waiting for network connectivity

• Is there a specific order required for modem/LTE/GNSS init when used with CoAP?

• Any debugging tips to see why GNSS events never trigger and CoAP never sends?

Additional info

• Board: nRF9151 DK

• SDK: nRF Connect SDK v3.0.0

• Both examples work independently

• Using IPv6 CoAP server

Any guidance or example on how to properly combine GNSS fix + CoAP POST would be greatly appreciated.

Regards 

Arun

[dejans]

Hi Arun,

Arun538 said:

when I am moving (even while walking), it is not working or giving a fix.

What is the difference in cases when "it is not working" and not "giving a fix"? Can you provide additional details? Do you have any logs which you can share? 

Can you also provide more information about your testing environment?

Best regards,
Dejan

[Arun538]

Hi Dejan,

Thanks for your response.

When I mentioned “not working,” I meant that while the device is moving (even walking), the GNSS is not able to get a valid fix, and I only see repeated logs about searching for satellites. When the device is stationary outdoors, I can get a fix within a reasonable time.

I don’t see any fix flags set in the moving case. The environment is outdoors (open sky), and I’m testing while walking in an open area without tall buildings nearby.

Do you think additional configuration is required for GNSS to track properly while the device is moving? Or is there a recommended mode that works better?

Best regards,
Arun

[dejans]

Hi Arun,

Arun538 said:

When I mentioned “not working,” I meant that while the device is moving (even walking), the GNSS is not able to get a valid fix, and I only see repeated logs about searching for satellites. When the device is stationary outdoors, I can get a fix within a reasonable time.

Arun538 said:

Because when I test indoors, I don’t get location, but outdoors it works.

Is it that when the device is outside and moving (as well as inside), it cannot get a fix?
In your testing, did you use your own application or (unmodified) GNSS sample?

Best regards,
Dejan

[Arun538]

Hi Dejan,

Yes, that’s correct. When the device is outdoors and stationary, I can get a fix. But when the device is outdoors and moving (even while walking), it cannot get a fix — it just keeps logging “searching for satellites.”

I also tested the same unmodified GNSS example indoors, but I’m not able to get a fix there either.

Best regards,

Arun

[dejans]

Hi Arun,

Have you tried to reset your dk board and wait longer time until you get a fix?

In indoor environment, it is not expected that you can get GNSS fix reliably. You can look at cellular or wi-fi locationing (SSID Wi-Fi locationing) as an alternative. Additional information can be found in Location Services. Can you provide details about your outdoor environment? When moving, where and how have you kept the board? Can you provide more information about the type of movement? Did you test GNSS sample only when walking?

Best regards,
Dejan