nRF9160 GPS configurations and fixing issues

[Grigor]

Hi.
I’ve developed a custom device based on nRF9160 and now have a problem of fixing GPS signal.
With the same antenna and same conditions sometimes it takes up to 10 minutes to fix, sometimes, 1 minute some times 2 hours and there is no any consistency.
In the datasheet of nRF9160 I found a specification about current consumption of GPS and here there are 3 modes of operation:
•    Continuous tracking, typical peak current without power saving mode
•    Continuous tracking, power saving mode
•    Single shot, one fix every 2 minutes
Could you please inform me which mode is default one? How I can change the operation mode an which mode will provide the best performance for GPS fixing?
In the chapter 8 of the objective product specification of nRF9160 there is an antenna options list. Do I need to configure the antenna type that I’m using in my device and if yes, how to do this?
Thank you.

[Hakon]

Hey,

 

Could you please inform me which mode is default one? How I can change the operation mode an which mode will provide the best performance for GPS fixing?

 You can find information about the gps modes here. There is no "default" mode as far as I understand though. The modes can be set in nrf_setsockopt().

 

Do I need to configure the antenna type that I’m using in my device and if yes, how to do this?

 Can you clarify what you mean by "configure the antenna type"?

[Grigor]

Hi Hakon. Thanks a lot for your reply.

Hakon said:

 You can find information about the gps modes here. There is no "default" mode as far as I understand though. The modes can be set in nrf_setsockopt().

Actually the link that you've provided is not working, it can't open.

http://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/bsdlib/doc/api.html#gnss-socket

Is it possible to change the mode of GPS operation through AT commands?

Hakon said:

Can you clarify what you mean by "configure the antenna type"?

As for antenna I mean these note from the datasheet

I have one more question.

Currently I'm facing one more issue. When LTE mode is in PSM I'm trying to fix GPS coordinates, but even keeping in this mode more than 2 hours I'm not getting any fix.

The nRF9160 captures up to 12 satellites but GPS is not fixing. Once I disable LTE it fixed within 6-7 mins.

What is wrong in my operations?

I can send you the AT commands that I'm using to configure the module if required.

Thank you.

[Hakon]

Grigor said:

Actually the link that you've provided is not working, it can't open.

 The link is working perfectly fine, at least in my browser(Firefox).

 

Grigor said:

Is it possible to change the mode of GPS operation through AT commands?

 Not that I'm aware of.

 

Grigor said:

As for antenna I mean these note from the datasheet

 You should follow the guidelines in this document. It is recommended that you use a separate antenna for GPS and LTE.

 

Grigor said:

Currently I'm facing one more issue. When LTE mode is in PSM I'm trying to fix GPS coordinates, but even keeping in this mode more than 2 hours I'm not getting any fix.

 For better GPS performance, you should consider using A-GPS. You can try the nrf_cloud_agps sample project and see if it helps. Also if you haven't done it, you should upgrade the modem firmware to the latest release.

[Grigor]

Hakon said:

The link is working perfectly fine, at least in my browser(Firefox).

Something is strange with this link. I'm also using Firefox and it's not opening. I tried to open in another PC with Chrome not opened. Tried to open in another PC with both firefox and chrome, the same result not opening. I tried to connect to another network to change my IP, also no result. But the same link opened in my phone without any problem:) Will try to clarify the issue in my side.

[Grigor]

Hakon said:

You should follow the guidelines in this document. It is recommended that you use a separate antenna for GPS and LTE.

Yes, we are using 2 different antennas for GPS and LTE.