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

[mlang3440]

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

[jwhite]

I am having almost exactly the same issue, but with an out-of-the-box nRF9160DK running the GPS example with NCS v1.2. Since there is no verified answer here, I will present my question here. Here is my setup:

I received a nRF9160DK two weeks ago, and I was able to get it up and running with the Asset tracker firmware, and I was also able to get the GPS example working after flashing it from SES. After about 30-60 seconds, the gps example would get a fix and start printing out the nmea data on the nRF connect link monitor. I was able to get a fix indoors with the patch antenna provided.

But now, when I start up the nRF9160DK running the GPS example, it sits and prints out that it sees anywhere from 6-9 satellites, but it never finds a fix. I have let it sit for hours to no avail. I am not using the SUPL library because I want to run the GPS without LTE active. I've also tried going outside, switching from the onboard antenna to the external antenna, and restarting/re-programming the application. I seem to be stuck in the case that mlang said, but I never get out of it. Is there anything else I can try for this issue?

Here is a screenshot of the link monitor while the GPS example is running:

[Øyvind]

Hello jwhite,

What modem version are you running? Have you tested it outside in the open?

As stated in the nRF9160 DK documentation:
"GPS signals do not usually penetrate ceilings or other structures that well. Therefore, for best GPS performance, the DK should be placed on a flat surface in an open space outside, far from sources of interference and other structures that may block the signals from space."

If you are experiencing more issues, please register a new ticket regarding your issue.

Kind regards,
Øyvind

[RicardoPereira]

Hi, 

I'm having the same issues as jwhite  with my thingy:91.

I can get up to 9 tracking but never get fix. I have the firmware 1.2.0. 

Any ideas ?

Regards, 

[jwhite]

RicardoPereira I was having this issue indoors, using a large passive GPS antenna. I moved my nrf9160dk closer to my window and it was able to get a fix only using 5 satellites within 45 seconds. I never got an answer as to why a fix could not be found using 9 satellites, and I could not find a forum post that digs farther into this issue.

[LordLucan]

I too have hit this trough of tracking a number of satellites but never getting a fix. The GPS was working reasonably well. All of a sudden since yesterday it just cannot get a fix. My nrf9160_pca10090 is sitting in an open space outside on the grass. It is tracking about 12 satellites, using 0, it has been like this for about an hour. I'm just using the GPS sample. I'm using the external active GPS antenna supplied. Firmware version 1.2.

There are a number of threads on this forum with similar issues of the GPS just not being able to fix despite tracking a number of satellites. Is Nordic invetigating this issue or suggesting a workaround to reset the modem?

Regards,

Paul