GPS

[pemar13]

Hi!

We have been experimenting with the nRF9160's GPS using both one of our own custom board and the Development Kit v 0.8.5 (with similar results).

We run the gps sample app in ncs version 0.4.0 using the FW 0.7.0-29.alpha.

We manage to "lock" the GPS and get valid PVT data after typically 2-4 minutes when we are outdoors. When we are indoors at an open window things work less well and often not at all.

These results are not really to our satisfaction. Since the antenna of the latest DK is supposed to be matched and the antenna on our custom board is pretty well matched, it is unclear why performance isn't better, but we hope things will improve. Do you have any comments on this?

Furthermore, the GPS API isn't extensively documented. Although it certainly is possible to figure out how to use it using the nrf_socket.h file and the gps sample, some more documentation would be welcome. Is this planned?

One detail in the code is not clear. In the GPS sample’s main.c, procedure print_satellite_stats, line 163, the counter in_fix is incremented when NRF_GNSS_PVT_FLAG_FIX_VALID_BIT is set in pvt_data->pvt.sv[i].flags. Looking at nrf_socket.h line 177, it would seem that NRF_GNSS_SV_FLAG_USED_IN_FIX should be tested instead. Do you have any comments on this?

Finalyly, the latest FW 0.7.0-29.alpha does not support GPS and NB-IoT concurrently. For when is this important functionality planned?

Best regards,

Per

[Kaja]

Hi Per,

so first: 

One detail in the code is not clear. In the GPS sample’s main.c, procedure print_satellite_stats, line 163, the counter in_fix is incremented when NRF_GNSS_PVT_FLAG_FIX_VALID_BIT is set in pvt_data->pvt.sv[i].flags. Looking at nrf_socket.h line 177, it would seem that NRF_GNSS_SV_FLAG_USED_IN_FIX should be tested instead. Do you have any comments on this?

 - I have forwarded this internally and you are correct, there will be made a fix, thank you for pointing it out! 

As Evan pointed out, the "cold start" is as expected today, and it's about the same time as it is with an external antenna on the DK. The GPS API is not final and we are still working on it, the rest of the questions you have, you have to direct to your regional sales manager. 

If you want, you can upload you design files, if you want a review.

Best regards,
Kaja