Can I use GNSS positioning while maintaining LTE-M or NB-IoT connectivity simultaneously?

LTE-M / NB-IoT (Monarch)
1

Hello

It seems that GNSS is non-concurrent to LTE-M or NB-IoT operation on the GM02SP or the SKY66431. For a tracker application, that is fine, but do I need to disconnect from LTE-M or NB-IoT whenever I want to get a GNSS fix?

Can I use the “off” periods of LTE-M (e.g. while in PSM or in CFUN=4) to handle the GNSS part?

I want to make sure I can keep my LTE-M connectivity and don’t have to detach / re-attach every time I need to get a GNSS fix.

Thanks in advance!

BTK

2

Yes, your understanding is correct. GNSS and cellular connectivity (LTE ) are non-concurrent. Nad the modem does need to disconnected from LTE-M or NB-IoT whenever the application wants to get a GNSS fix?

Yes you can use the “off” periods of LTE-M (e.g. while in PSM or in CFUN=4) to handle the GNSS fix. Please note that OFF period(PSM timers) should be long enough to allow to get the GNSS fix.

1 Like
3

Thanks - I already noted that I can get a (hot) fix within a few seconds (quicker than I expected), but to be on the safe side, I am provisioning up to 1min in case of a cold fix.

My app would typically fetch a fix every 30min (and then send to my cloud) when the tracker is in motion (using an accelero-gyro). I can keep the previous ephemeris for that.

Typical application cycle would be, when the tracker is in motion: get a fix (while in PSM), wait one min, reregister/send to my cloud, and then go back to PSM… and every 2hours, get an ephemeris update before going back to PSM. When the tracker is not in motion, I will likely go to CFUN=0 (or airplane mode) to be safe.