GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

RE: GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

tpg — Thu, 25 Jan 2024 15:37:24 GMT

Thanks for your help, I actually found the solution, and as usual we where looking in the wrong direction. Seems with 2.5 some code around the ADP5360 PMIC changed, so we aligned our board config to updated ADP5360 initialization of the asset tracker example. Seems, some entry in the device tree was needed.

In the end the GNSS LNA was simply not powered.

RE: GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

Øyvind — Thu, 11 Jan 2024 12:54:35 GMT

Just drag the file to the reply field, or go to insert and click on Image/video/file then click on "upload"

Kind regards,
Øyvind

RE: GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

tpg — Wed, 10 Jan 2024 17:55:11 GMT

how could I send you the trace?

RE: GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

Øyvind — Mon, 08 Jan 2024 10:30:45 GMT

I reached out to our developers.

Make sure LTE is not blocking GNSS by checking that NRF_MODEM_GNSS_PVT_FLAG_NOT_ENOUGH_WINDOW_TIME and NRF_MODEM_GNSS_PVT_FLAG_DEADLINE_MISSED flags are not set in PVT notification when GNSS is running (https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/nrf_modem/doc/api.html#pvt-notification-flags-bitmask-values)

[quote user="tpg"]I currently don't have traces or a log, I can see about creating new logs.[/quote]

Yes, that would be helpful as it would provide more insight to the root cause. Modem traces would be preferred with the application logs, as this gives more information on what is going on inside the modem.

[quote user="tpg"]What is the binary format of the agps/agnss data here, where is this documented?[/quote]

The binary assistance data format is described here: https://github.com/nrfconnect/sdk-nrf/blob/v2.5.0/subsys/net/lib/nrf_cloud/include/nrf_cloud_agnss_schema_v1.h

The changes in v2.5.0 are cosmetic. The data schema and the used MQTT AppID have not been changed, so the cloud communication should be the same as with v2.4.0.

Make sure LTE is not blocking GNSS by checking that NRF_MODEM_GNSS_PVT_FLAG_NOT_ENOUGH_WINDOW_TIME and NRF_MODEM_GNSS_PVT_FLAG_DEADLINE_MISSED flags are not set in PVT notification when GNSS is running (https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/nrf_modem/doc/api.html#pvt-notification-flags-bitmask-values)

RE: GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

tpg — Fri, 05 Jan 2024 16:06:58 GMT

The modem is on firmware 1.3.5, I currently don't have traces or a log, I can see about creating new logs.

The A-GNSS data is requested and was received, nrf_cloud_agnss_process happly processes this data, the last time I created a log.

What about my last questions in the previous post does the v2.5 sdk work with data from the agps, instead of the agnss, REST endpoint? What is the binary format of the agps/agnss data here, where is this documented?

Best regards

RE: GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

Øyvind — Fri, 22 Dec 2023 11:27:00 GMT

Thanks for clarifying? What modem FW version are you running on your device? Are you able to provide modem traces from both 2.4 and 2.5 for us to compare? Do you have any logs that you can share?

Kind regards,
Øyvind

RE: GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

tpg — Wed, 20 Dec 2023 14:06:02 GMT

Partially we use the nrf Cloud A-GNSS library. The overall structure/code is close to the asset tracker v2 (with roots down to connect v2.3 and ported to v2.4).

The flow is very similar:

We get a LOCATION_MODULE_EVT_AGNSS_NEEDED event
We encode a agnss request (or two one for almanac one for ephemeris if needed)
We send it to an mqtt topic (AWS iot)
The backend forward this to nRF Cloud rest API
The result is published over mqtt to the device
The agnss handler uses nrf_cloud_agnss_process (nRF Cloud A-GNSS library) to send the data to the modem.
1. in case the almanac/ephemeris is splitted we call the function twice, once for each reply

This works with perfectly with v2.4 and it seems to work with v2.5 going through all steps and nrf_cloud_agnss_process returns OK for almanac and ephemeris. Just that with v2.5 the modem has a hard time to find GPS satellites, as if there was no A-GNSS data.

The changes to v2.5 here are only in changing the names of everything (datastructures, events, apis) from A-GPS to A-GNSS.

So concrete point I found now is, that there is a new REST endpoint location/agnss and agps is marked deprecated. Is it required to upgrade the backend to use the new endpoint?

And is there a description of the binary format for the A-GNSS data? Has this changed?

RE: GNSS/GPS TTFF with A-GNSS after upgrade from v2.4 to v2.5

Øyvind — Wed, 20 Dec 2023 12:49:15 GMT

Hello,

Are you seeing the same issue if using e.g. cellular GNSS sample? Are you using A-GNSS/GPS

[quote user=""]A-GPS data we get via MQTT, but we split almanac and ephemeris.[/quote]

I assume that you are not using our nRF Cloud A-GNSS library, could you please elaborate more on how your method works?

[quote user=""]Now to upgrade to v2.5 we made the changes from agps to agnss[/quote]

What changes have you done?

Kind regards,
Øyvind