Getting GPS fix with nRF9160-DK and Thingy:91

[bojan]

Hello guys.

Here with me I have both nRF9160-DK, hardware version 0.8.3 and Thingy:91 boards.
I am on the nRF Connect SDK tag 1.2.0 and have nrf9160 SiP modem firmware updated to 1.1.1 version.
When trying only gps example that I found under samples/nrf9160/gps I was unable to get any GPS fix even when using external antenna (TW4020 from Talysman):

Scanning [-] [1;1H[2JTracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 1742

Scanning [\] [1;1H[2JTracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 1743

I know there is some issue with the iBasis SIM roaming cards and local carriers (I am located in France, by the way) that does not allow entering PSM mode. Is this issue occuring in GPS-only example as well? To the best of my understanding, LTE is not active in GPS example.

I don't see any switch on 0.8.3 version of nRF9160-DK board for a selection between on-board/external GPS antenna, am I missing it? Do I need to do something more in addition to connecting external GPS antenna to appropriate connector?

I even tried with some Orange SIM card thinking it is a local card but this card is, to the best of my understanding, registered as a roaming card under other carrier (Bouygues):

Where would be the right place to ask for appropriate SIM cards?

Finally, I was happy to watch your webinar about SDK v1.2 and new exciting GPS solutions (SUPL, A-GPS...). Would that things make our GPS connection easier or we would still need to resolve the issues with local carriers (entering PSM mode...)?

Thanks for your time and efforts.

Sincerely,

Bojan.

[Pete Skeggs]

I'm not sure the detailed differences between 9160DK 0.8.3 and 0.8.5, but, version 0.8.5 has a tiny SW12 near the GPS antenna connector.  Switch it in the CON position to use the connector, or the ANT position to use the on-board antenna.

[bojan]

I was unable to see any switch near GPS antenna in 0.8.3 version. I bought the board from Mouser few weeks ago so I wonder why the latest version is not delivered to me!?

[Karl Ylvisaker]

Hi Bojan,

I am sorry to hear that you are having trouble using the GPS.
This is an errata on some of the boards with hardware version 0.7.0, 0.8.2 and 0.8.3, which is documented here.
The errata makes the affected boards unable to use their on-board antenna for GPS, and thus needs to use an external antenna.
From your description and attached logs, it seems like your DK is one of these boards - please see this guide on how to enable an external antenna with your board.
Please let me know if this does not solve your problem.

Now, over to your other questions:

I know there is some issue with the iBasis SIM roaming cards and local carriers (I am located in France, by the way) that does not allow entering PSM mode. Is this issue occuring in GPS-only example as well? To the best of my understanding, LTE is not active in GPS example.

Yes, there is an issue that some carriers does not support PSM for roaming registered SIM cards. This issue is occurring when only using the GPS as well.
It is up to each carrier to support PSM mode - some of the largest carriers already does this, but far from all. Unfortunately, there does not exist a register or list of which carriers supports which operating modes - so the best way to confirm this is to contact your carrier directly.
However, most of them support PSM for their home-registered SIM cards. 
You are also correct in your understanding that LTE is not active in the GPS example, only GPS is used.
 

I don't see any switch on 0.8.3 version of nRF9160-DK board for a selection between on-board/external GPS antenna, am I missing it? Do I need to do something more in addition to connecting external GPS antenna to appropriate connector?

You are also correct that the nRF9160-DK with hardware version <= 0.8.3 does not have a switch for selection between on-board and external GPS antenna. Please see the guide I linked earlier for information on how to use an external antenna with your board. 

Where would be the right place to ask for appropriate SIM cards?

I am not sure I understand exactly what you are asking, but you can ask each carrier where their SIM cards are home registered, and if they support PSM for their home registered cards(which is true in most cases).

bojan said:

I bought the board from Mouser few weeks ago so I wonder why the latest version is not delivered to me!?

I am unable to answer why Mouser delivered you an older hardware version board, but I suggest you contact them and ask if you can get a newer version instead.


Best regards,
Karl 

[bojan]

Hey, Karl Ylvisaker!

Thanks for your feedback!

I tried GPS example with Thingy:91 board as well but to no avail. This would imply that the issue is with the SIM card as well. Will try to get some local card that supports PSM mode.

Sincerely,

Bojan.

[Karl Ylvisaker]

No problem at all, I am happy to help!

That sounds like a good approach. Let me know if you encounter any other issues or have some more questions in the future.

Best regards,
Karl

[bojan]

Karl Ylvisaker,

I have TW4020 external antenna from Tallysman as well as MXHS83QE1000 adapter cable from Murata. I see the mentions of bias tee for external GPS antennas that are active.

Do I need Bias tee for Thingy:91 board and TW4020 external antenna? If affirmative, how can I mount it on Thingy:91 board?

Regards,

Bojan.

[bojan]

Karl Ylvisaker, TW4020 seems to be an active antenna with Bias Tee needed. In many of your posts (e.g. here or here) you say all we need is an adapter (like the MXHS83QE3000) and external antenna.

Anyway, according to this post, there is a chance we get GPS fix if we use GPS in GPS/GNNS standalone mode with LTE mode turned off. Is it enough to apply 

"AT\%XSYSTEMMODE=0,0,1,0"

 command to select GNSS support only or we need to explicitly turn off LTE mode somehow?

Sincerely,

Bojan.

[Karl Ylvisaker]

Hi Bojan,

bojan said:

Do I need Bias tee for Thingy:91 board and TW4020 external antenna? If affirmative, how can I mount it on Thingy:91 board?

Yes, like you mention in your latest reply - all active antennas need Bias Tee. When connecting the external antenna, the bias tee needs to be connected between the SWF connector and the external antenna cable. The SWF connector is marked "J2" on the hardware illustration on this page.

bojan said:

Anyway, according to this post, there is a chance we get GPS fix if we use GPS in GPS/GNNS standalone mode with LTE mode turned off.

 The post you reference is in regards to having LTE and GPS run concurrently, which requires PSM(but you may do the procedure Sigurd describes, if you need to use both). Unfortunately, activating standalone GPS mode does not improve GPS antenna performance, and the external antenna is still needed.

bojan said:

 command to select GNSS support only or we need to explicitly turn off LTE mode somehow?

By running the AT-command you suggest, you disable LTE and enable only GPS, which is correct. Remember to also use the Set command to activate your GPS module, in addition to enabling it.

Best regards,
Karl

[Karl Ylvisaker]

Hi again Bojan,

I have checked with some of my colleagues about this issue, and it seems that using an active external GPS antenna with the Thingy:91 at times can be very frustrating.
The main reason for this seems to stem from the added loss by the required external components.
Are you currently developing primarily on the nRF9160-DK, or the Thingy:91?

Best regards,
Karl

[bojan]

Hello, Karl Ylvisaker.

We are prototyping with Thingy:91.

I tried with Thingy:91 on-board antenna and GNSS/GPS mode and was able to get the fix in about 110 seconds by putting the Thingy outside my window. The accuracy of the location is quite satisfying. With external antennas, SUPL, A-GPS and the things you announced in your latest webinar about SDK v1.2, I guess this will be a success story!

This about external active antenna and Thingy:91 is quite important information. You are obviously internally aware of that weakness but there is no will from your side to spread that info to the community in a clear way. By reading your posts (e.g. this one), I first though all I need is adapter cable and external antenna. Then, in the meantime, after hours of error and trial, I realized I need a Bias tee as well because the antenna is active. I ordered the Bias tee and now it seems that there is some issue with Thingy:91 and active external GPS antennas. Quite frustrating!

We started with our product development almost two months ago and at that point I convinced the team to go with Nordic solution based on my prior Nordic experiences (mainly around nRF52 BLE modules). During the past 2 months, we spent 90% of the time in setting up the environment and we still feel the pain! There is a nRF52840 module on the Thingy board but it mainly serves as nRF9160 controller and debugger. It is quite difficult to keep that debugging feature inside nRF52840 and add some BLE services on the top of that. I still desperately wait for your feedback on that topic (this thread).

nRF9160-DK boards with some hardware faults (0.8.3 and older) are still on the market. I contacted Mouser, as you suggested, to find out why did they send me the old version and they simply said they are selling from their stocks in a FIFO manner. It is not their fault, they are just selling what you provided them.

I start feeling bad and guilty because I convinced people to go that way. Let me be clear here, I don't have any doubt you are working hard in the background to provide us a high quality development environment. Neither I have doubt your products are great (even the best on the market)! But my managers are not technical people, they just see we are eating time and budget at the moment.

More useful examples, more stable development environment with easy debugging possibilities, more responsive technical support, spreading the info in a clear way... all that is needed if you want to keep your image on the market!

Until the day I begin feeling proud and managers start tapping my shoulders on the corridors, I am sending you my best regards! Let's all grow together!

Cheers!

Bojan.

[Karl Ylvisaker]

Hello Bojan,

Sorry for my late reply.

bojan said:

We are prototyping with Thingy:91.

With the troubles you describe, you may have an easier time prototyping your GPS features on your nRF9160-DK, instead of on the Thingy:91.

bojan said:

With external antennas, SUPL, A-GPS and the things you announced in your latest webinar about SDK v1.2, I guess this will be a success story!

Yes, this is an errata we are working diligently to alleviate, and the new version will improve performance.
I am glad you enjoyed the webinar!

bojan said:

You are obviously internally aware of that weakness but there is no will from your side to spread that info to the community in a clear way.

The errata on the nRF9160 has been known for some time, as it is documented here and here.
I agree with you that we should increase our efforts to communicate clearly the workaround for this errata.
Especially the parts concerning the additional required components to achieve satisfactory GPS performance.
I am very sorry to hear that your experience with this product has been frustrating, and internally we have opened an issue regarding the current state of the external antenna communication. I will let you know as soon as it has been resolved(even though you have already gone through this, know that it will be addressed).

bojan said:

I convinced the team to go with Nordic solution based on my prior Nordic experiences (mainly around nRF52 BLE modules).

I am glad to know that your previous experience with us has been more pleasant, and that you would recommend our products to your team! 

bojan said:

More useful examples, more stable development environment with easy debugging possibilities, more responsive technical support, spreading the info in a clear way... all that is needed if you want to keep your image on the market!

Thank you Bojan, for all your feedback on this issue - I have documented it, and forwarded it to the appropriate people.

Best regards to you as well!

Karl

 

[Karl Ylvisaker]

Hello again, Bojan

This might not be relevant for you anymore, but I thought I should provide an update on the matter since I promised that I would in my previous reply.
In summary, to clarify the GPS antenna issue of the Thingy:91 v1.0.0 we published an Errata for the issue.
This errata has also been addressed in later releases of the Thingy:91 (after v1.0.0), where GPS performance is increased. There is however a known issue with using the GPS of the Thingy:91 while the USB is connected, as this degrades performance. For best performance, it is also recommended to make use of AGPS.

Thanks again for the feedback you provided on this!

Best regards,
Karl