GPS UDP Project: Invalid PVT Frame, GPS Seconds Last Fix ERR

[Thomas]

Hi, i have been trying to get GPS and HTTP to be able to work with eachother, but im having some struggles.

After the GPS starts, the program begins spewing out "Invalid PVT Frame, Discarding" not sure if that is intentional.

Then once that ends after a minute or less it begins tracking satellites, but it does not ever use any.

I have tried with only gps with the gps sample, and that takes maby 2-3 minutes to get all 4 satellites, (3 in less then a minute) and it got tracking location, but not with this project.

At the same time, there is no seconds on fix, and just returns ERR. And the satelitte are "Not Used".

Here is the code/repository which is forked from Rallare's: https://github.com/ThomasAunvik/fw-nrfconnect-nrf/tree/nrf9160_samples/samples/nrf9160/udp_gps

Here is the log file: https://gist.github.com/ThomasAunvik/faa07b994b1a1e7c19ade7b67748bcb8

Modem Firmware Version: 1.1.0

nRF9160 DK 0.8.5

[Håkon Alseth]

Hi,

 

The log shows:

2020-01-30T13:18:15.148Z DEBUG modem << +CEREG: 5,"76C1","014A4703",7,,,"11100000","11100000"\x0D\x0A

The returned 5 indicates that you're using a roaming SIM card:

5 – Registered, roaming.

 

On most networks, roaming SIM cards are not given PSM. the upper bits in the CEREG readback also decodes to "disabled". Since the GPS will only give you a valid fix in PSM or eDRX, the sample will unfortunately not work as intended on your side. If you get a hold of a home registered SIM, it is likely that you get PSM.

Regarding the ERR printed as timestamp, I can confirm this bug is present.

 

Kind regards,

Håkon

[Thomas]

Does it require a psm supported sim card for gps to work with LTE? If so does LTE-M (NB-IoT) from Telenor work?

[Håkon Alseth]

Hi,

 

Thomas said:

Does it require a psm supported sim card for gps to work with LTE? If so does LTE-M (NB-IoT) from Telenor work?

Yes, to get the gps running concurrently with the network connection, you must be able to enter eDRX or PSM. A telenor SIM, that is M1 or NB1 capable, shall be able to enter PSM.

 

Kind regards,

Håkon

[Thomas]

Hi, thanks that worked, but there is still some issues that im having regarding the gps position fix.

Apparently this NMEA returns incorrectly. 

$GPGGA,160142.27,6326.59256,N,01025.77435,E,1,04,19.03,88.15,M,0,,*25

And gps_data.pvt returns almost 0.