Transmit GPS data to website

[tracking]

Hello 

I would like to transmit gps data to my website in addition to nrf cloud, there is a example or documentation about this that I can take of reference? I am working with nRF 9160 DK 

thanks in advance.

Kind Regards

Julio

[Håkon Alseth]

Hi,

 

The asset_tracker shows how to connect to a cloud based system, and send certain sensors + gps data to the cloud.

If you want a simpler solution, like a tcp/udp connection directly to your own server, I would recommend that you look at the "gps" sample, and add your own implementation around this.

 

Note that there's a restriction towards getting GPS and LTE concurrent, which is that you have to be in eDRX or PSM mode in order to use the GPS. A recommended use-case is to use the AT CSCON event to signal when you can or cannot use the GPS.

 

Kind regards,

Håkon

[paul_tanner]

Thx Håkon,

I tried setting CSCON=0 when initialising the GPS.

(After looking at the code in asset_tracker I also saw it use lte_lc_psm_req(true))

If I then try to initialise a UDP connection lte_lc_init_and_connect_async(lte_handler) fails.

(Initialisation code from the UDP example)

I'm not clear on the sequence I need to initialise both GPS and UDP.

further...

I wanted to see why lte_lc_init_and_connect_async is failing but this seems to be part of the distribution that is shipped in binary.

Specifically, the error is:

modem_configure()
I: Using legacy LTE PCO mode...
I: PDP Context: AT+CGDCONT=0,"IP","lpwa.vodafone.iot"
E: Could not send AT command, error: -8

Which is odd because when initialising the GPS we already sent 4 AT commands without error.

This part of UDP initialisation works fine if I comment out the GPS initialisation 

Thx.

[Håkon Alseth]

Hi,

paul_tanner said:

I tried setting CSCON=0 when initialising the GPS.

 This is an event coming from the modem, which indicates if the LTE link is active or not. You should set the CSCON non-zero to enable notification, and then you should get it through your AT notification handler (if set).

By setting it to 0, you're disabling the notification.

 

paul_tanner said:

If I then try to initialise a UDP connection lte_lc_init_and_connect_async(lte_handler) fails.

 Is "CONFIG_LTE_AUTO_INIT_AND_CONNECT" disabled? If this is enabled, the link is enabled and established prior to entering main. 

 

paul_tanner said:

I'm not clear on the sequence I need to initialise both GPS and UDP.

You first need to enable the usage of GPS, for instance by enabling CONFIG_LTE_NETWORK_MODE_LTE_M_GPS=y (or if NB1: CONFIG_LTE_NETWORK_MODE_NBIOT_GPS)

This will set the permission in AT%XSYSTEMMODE.

If you are able to successfully enter PSM or eDRX, and you have ensured the CSCON event is enabled (See the docs here: https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/packet_domain/cscon_set.html?cp=2_1_6_16_0), you can start the GPS, as shown in the "gps" sample.

 

The CSCON event is available through the lte_lc library, and samples like the udp/cloud_client/asset_tracker, implement a print when you're connected or idle:

https://github.com/nrfconnect/sdk-nrf/blob/master/samples/nrf9160/udp/src/main.c#L79-L82

 

when CSCON (or lte_lc::LTE_LC_EVT_RRC_UPDATE) gives you a notification "idle", you can start the GPS.

 

Kind regards,

Håkon

[paul_tanner]

Many thx Håkon

I guess this means that if testing without a connection it will wait indefinitely - if you let it.

That should not be a problem as you can't send anything until you get a signal.

I'll try this when I'm in range of a cell tower.

Regards, Paul

[Håkon Alseth]

You can evaluate the gps without using LTE, by running the "gps" example.

This doesn't require LTE, but does require that you're outside (or the GPS-antenna shall be outside) while testing.

 

Kind regards,

Håkon

[paul_tanner]

Thx Håkon

Yes.  The first thing I did was to test both GPS and UDP examples.

Only then did I try to put them together to make a minimal tracker using UDP and without the need for all the other good stuff in your asset_tracker app.

So I now wait for udp Idle.

However, from the code in the gps sample I then get an error from

```

at_cmd_write(at_commands[i])

```

AT_XSYSTEMMODE,  (fails on this one)
AT_MAGPIO,
AT_COEX0,
AT_ACTIVATE_GPS

so GPS is not activated.

XSYSTEMMODE is probably redundant but why would it throw an error?

Regards.

[Håkon Alseth]

Hi,

 

paul_tanner said:

XSYSTEMMODE is probably redundant but why would it throw an error?

Its highly likely because the modem is already enabled (AT+CFUN=1) at this point. Please check that "modem_configure()" isn't called, and that "CONFIG_LTE_AUTO_INIT_AND_CONNECT=n" is set in your project.

 

Kind regards,

Håkon

[paul_tanner]

Thx Håkon

modem_configure() *was* being called; CONFIG_LTE_AUTO_INIT_AND_CONNECT=n is set.

So I removed modem_configure().  The result was that we never get the LTE_LC_EVT_RRC_UPDATE (idle) event so it just hangs.

Is something else needed instead of modem_configure()? (per the udp example)

Presumably the lack of modem_configure would also prevent sending of data via udp?

Regards.

[Håkon Alseth]

Hi Paul,

 

My strongest apologies! This comment from me is written a bit too fast (ie: its wrong..)

Håkon Alseth said:

Please check that "modem_configure()" isn't called

You should check that modem_configure hasn't been called yet, before setting system permissions, like XSYSTEMMODE.

So, issue your AT-commands, then call modem_configure() to connect to the LTE network.

 

Kind regards,

Håkon 

[paul_tanner]

Thx Håkon 

I tried that.  It gets to modem_configure() - same code as in UDP sample - and we then fail with:

```

Could not send AT command error -8

```

This is happening inside lte_lc_init_and_connect_async() for which AFAIK we do not have the source.

Regards.