Periodic GNSS vs single shot behavior

[thomasGronroos]

When running the modems gnss in single shot mode with external 600 second interval timer and periodic mode with the same 600 second interval, what differences are there in the modems behavior?

For example are there some different optimization how previous valid fixes are used to aid in the next fix, how often is a-gnss requested?

What I could gather from the gnss configuration documentation is that in periodic mode the gnss performs scheduled downloads for some gnss parameters and that this could be disabled if a-gnss is in use, but other than that I did not see any documentation of any differences.

[Håkon Alseth]

Hi,

 

GNSS modes available are shown here:

https://nrfconnectdocs.nordicsemi.com/ncs/latest/nrfxlib/nrf_modem/doc/gnss_interface.html#configuring-gnss

 

Your scenario here:

When running the modems gnss in single shot mode with external 600 second interval timer and periodic mode with the same 600 second interval, what differences are there in the modems behavior?

lists "single fix" and "periodic navigation" with the exact same timing parameters, ie. interval=600 seconds (10 minutes) and let's assume the timeout is similar as well.

There is no direct difference between these two setups.

For example are there some different optimization how previous valid fixes are used to aid in the next fix, how often is a-gnss requested?

What I could gather from the gnss configuration documentation is that in periodic mode the gnss performs scheduled downloads for some gnss parameters and that this could be disabled if a-gnss is in use, but other than that I did not see any documentation of any difference

if assisted gnss data is outdated, a callback/event is provided to the application. The application can then make a decision based on its own requirements on what to do with this event.

https://github.com/nrfconnect/sdk-nrf/blob/main/samples/cellular/gnss/src/main.c#L167-L177

 

Kind regards,

Håkon