Cold restart gps search - HOW? Without doing a nrf91 HW-reset

[Johan]

Hi,

We have a problem that occurs when

1) the GPS is at bootup of nrf91: indoor when we start the GPS search, and it doesn't find anything or maybe just 1 satellite. We then move outdoor, and still it stays forever and doesn't find anything. 

2) If we outdoor do a reset of the nRF91, it finds a fix within 30-60 sec. So conclusion the algorithm has gone into some strange search when it's failing firstly indoor.

QUESTION:

We dont want to physically reset the nRF91 to be able to "RECOVER" the gps search, ie cold start it.

How do we make the same happen in software?

I am doing this now, but fails:

gps_controller_stop();
gps_deinit(gps_device);

It doesn't seem to work that way.

Running: gps_controller_init() + gps_controller_start() again causes the below.

[00:01:22.915,405] <wrn> nrf9160_gps: GPS is already initialized
[00:01:22.924,926] <err> gps_controller: Could not initialize GPS, error: -120

Just stopping and starting the gps_controller works, but the search doesn't find ANYTHING.

So we don't have access to a working API right now.

Don't you offer a cold started gps search option? Do we have to HARD RESET the chip for this?
Seems weird solution.

Appreciate quick answer.

Best,

Johan

[Didrik Rokhaug]

Hi,

You can use the delete mask when starting the GPS through the socket API to delete the stored data: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/nrf_modem/doc/gnss_extension.html#starting-the-gps

The GPS driver will delete the stored data if you set delete_agps_data to true in the gps_config struct. However, there is no support for deleting the stored data in the gps_controller API.

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/nrf_modem/doc/api.html#c.nrf_gnss_delete_mask_t

Best regards,

Didrik

[Johan]

Thank you. We will explore this and see if we can get the COLD start behaviour, so it starts the search algorithm from start, with no preassumptions.