nrf9160 modem XFILEWRITE gps almanac

[LordLucan]

Hi,

I see in the nrf9160 1.2.0 AT document there is a command XFILEWRITE that suggests the GPS almanac can be written and persist in the modem.

Can you provide more documentation on this command and the format of the data you can write?

I'd like to improve the TTFF for the GPS. I've got the SUPL GPS client example working and it does indeed speed up TTFF to a few seconds. But I'd like to be able to store that information in the modem in cases where I have no LTE connection or it is simply unavailable for other reasons. That is I want the GPS data to persist. Suggestions welcome!

Regards,

Paul

[LordLucan]

Hi,

Thanks for this. What do you consider a "graceful power-down" of the modem, can you elaborate please?

How can I tell whether the almanac/ephemeris is out of date or not? ie when was it last updated?

I'm not seeing any evidence at the moment that this data persists. In the GPS sample with SUPL support the data is _always_ fetched. That is the modem sends out a NRF_GNSS_AGPS_DATA_ID request with just about all flags set. If the data is fetched then TTFF is very short, a few secs. If not then it can take about 30s. So clearly the data is not persisting at the moment.

Regards,

Paul