NRF_SO_GNSS_FIX_RETRY seems to have no effect for First Fix

[Marcel Graber]

Hi,

Perhaps I have a misunderstanding of this GNSS Socket Option.

In the GPS Sample Project (samples/nrf9160/gps) with a nrf9160-dk and no connected GPS Antenna, I set:

- Interval to 0 (Single Fix)

- Retry to 60 (60 Seconds timeout for getting Fix)

But the GNSS Module will not stop searching for the First Fix. Regarding the documentation, the GNSS Module should powerdown after 60 seconds.

Best,

Marcel

[Martin Lesund]

Hi Marcel,
From your description it does not sound that you are not running a timeout, every 60sec.

You may have mismatched something in your application.
Could you please double check what you are doing in the socket calls?

[Marcel Graber]

HI Martin,

Thank you for your feedback, perhaps I was not clear enough.

To reproduce this behaviour, I have used the GPS Sample, in the NCS (nrf/samples/nrf9160/gps), I do not use my own application. 

I have changed the following lines in main.c:

static int gnss_ctrl(uint32_t ctrl)
{
int retval;

nrf_gnss_fix_retry_t fix_retry = 40;
nrf_gnss_fix_interval_t fix_interval = 0;

I have removed the external Antenna and I use the DK indoor, so there is no chance to get a fix.

When I start this Sample App, the GPS Receiver will not stop searching after 40 Seconds.

.... or do I have a misunderstanding of the NRF_SO_GNSS_FIX_RETRY setting?

[anicare-tero]

Hi,

I'm using the release version 1.4.0 of the nRF Connect SDK which is pretty close to the master branch right now.

I'm having the same issue but in a different project. I have a custom board with a project code which is mainly based on the Asset Tracker application. I'm using the gps_controller like in Asset Tracker and the GPS timeout is not working similar than earlier.

For example with these values (timeout is same than retry)
   gps_cfg.timeout = 30;
   gps_cfg.interval = 30 + 30;
the GPS search will never stop and it just keeps going. The search just keeps going on.

So I guess there is some kind of bug in nrf9160_gps driver. Or then I'm doing something wrong.

I think my message belongs in this thread but I could make my own ticket if needed.

[Martin Lesund]

Hi,
Apologies for the confusion. 
I have checked internally and in there is actually search for a 60sec minimum for the first fix of the GPS independent of the retry-value.

This will be updated in the documentation.

[anicare-tero]

Oh yes it seems to be. Earlier I didn't even test it with a longer timeout than 30s because I wasn't going to get a GPS fix but just go through the program chain.

But thanks for telling that, it helped me a lot.