NRF9160: GPS Tracking satellites, but can't get fix.

Hi, we have a custom board using the nrf9160, running modem firmware 1.1, and using the nrf9160_gps driver.

Sometimes we see messages like this:

Tracking: 8 Using: 0 Unhealthy: 0

Where the GPS is tracking satellites but is not using any, and never gets a fix. Eventually we time-out and stop the GPS. But this behavior continues until the next device is restarted.

Is this a bug with the modem firmware? Is there any fix for this.

Thanks

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  • Hi

    Did you find the solution ? I'am having the same issue 

  • Hei Ricardo (and others having the same issues of seeing many satellites tracked, but no fix),

    There's a PR that can help us debug this issue a bit without capturing modem traces: https://github.com/nrfconnect/sdk-nrf/pull/2385

    This PR introduces NMEA-only output to the GPS sample (found in samples/nrf9160/gps/), which might help us narrow down what's going on.
    Until the PR is merged into NCS, you can experiment with it by using git and pull in the changes like this (assuming your NCS git remote is named "ncs", otherwise change it to your remote's name):

    git fetch ncs refs/pull/2385/head
    git checkout FETCH_HEAD (add " - b <branch_name>" if you want it on a branch)
    west update

    Now you have a new option in the GPS sample Kconfig. You can enable it by setting CONFIG_GPS_SAMPLE_NMEA_ONLY=y (note that it's default "n" /disabled  at the bottom line of the sample's prj.conf). After setting the option, you can build and flash using the tool you prefer.
    I'm attaching hex files for nRF9160 DK and Thingy:91:
    gps_sample_nmea_nrf91dk.hex
    gps_sample_nmea_thingy91.hex

    In the log output, you'll see NMEA strings only.

    You can share this log with us, and will see if we can see what's going on. Note that you can create a private ticket and share the files there if you prefer.

    In some cases, we'll also need modem traces to know exactly what's going on.

    Best regards,

    Jan Tore

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