Timing issue when GPS used with NB-IoT

[paul_tanner]

In SDK 1.4 we combined the udp and GPS examples and the result is unstable.

I think this could be because once enabled by RRC mode == Idle, GPS keeps going forever.

After getting a fix we want to send the data with location.  At this point it seems there is often a clash where GPS is fetching the next location.

I think we need to switch GPS off, send the data, delay a while and then switch it on again to get the next fix.

What is the proper way to do this pls?

Regards.

[helsing]

Could you please specify how you experience the result as being unstable?

In which mode is the GPS? Is it in continuous mode? LTE has priority over GPS so you do not need to turn off GPS in order to send over LTE.

However, you might need to make sure all data sent over the GPS socket is read. If the buffer shared between the application and modem is full you will not be able to send anything back and forth.

[paul_tanner]

Thanks and sorry for slow reply as I was held up from doing any further field tests.

Not sure what you mean by GPS "continuous mode".  I'm using the code from the GPS example.

Anyway, I removed any attempt to stop GPS.  This is working much better now but I do get at least one "GPS deadline missed" per UDP transmission.  This could be ignored but it might be better to pause GPS after a fix and wait until the UDP transmission is done.  I'm not sure how best to do that.