AGPS with SUPL with MQTT_Simple example

RE: AGPS with SUPL with MQTT_Simple example

Øyvind — Wed, 16 Jun 2021 09:00:18 GMT

Happy to help! 🙂

RE: AGPS with SUPL with MQTT_Simple example

Nahan_Trogn — Tue, 15 Jun 2021 15:09:52 GMT

Thank you for all your assistance

RE: AGPS with SUPL with MQTT_Simple example

Øyvind — Tue, 15 Jun 2021 06:38:29 GMT

Hello,

Glad to hear. Does this mean that you have solved your issue?

Kind regards,
Øyvind

RE: AGPS with SUPL with MQTT_Simple example

Nahan_Trogn — Tue, 15 Jun 2021 01:45:13 GMT

Hi,

If I use a config like the AGPS example, then I can use mqtt_simple with AGPS feature on mqtt_simple example base.

RE: AGPS with SUPL with MQTT_Simple example

Øyvind — Tue, 08 Jun 2021 10:48:57 GMT

Hi,

I'm trying to find a solution to this issue, and am currently working with our developers.

The initial question is: Have you tried implementing MQTT to the AGPS sample? If this sample works as intended, then maybe that would be an easier work-around.

Our SUPL expert had a look at you case, and says:

It seems that device gets some A-GPS data and writes that to the modem. It seems as if it couldn't read all of the data or something like that.

It takes a long time, so it can't be executed for example in the button handler directly. It should be ran in a separate thread. And the proper way to do it would be to fetch A-GPS data when GNSS asks for it. GPS driver sends event GPS_EVT_AGPS_DATA_NEEDED when it needs A-GPS data. That event contains a structure of type gps_agps_request which indicates what kind of A-GPS data GNSS needs. They should check the AGPS sample, it triggers the fetching of A-GPS data when GPS_EVT_AGPS_DATA_NEEDED is received by the event handler.

Kind regards,
Øyvind

RE: AGPS with SUPL with MQTT_Simple example

Nahan_Trogn — Fri, 04 Jun 2021 10:25:19 GMT

Hi,

I've followed your guide. I also set my mqtt alive time to 300s, but the same problem. I do the first start AGPS right after mqtt client connected Event and got -13 error; then I try start in RRC Idle event, also -13

devzone.nordicsemi.com/.../2021_2D00_06_2D00_04T10_5F00_01_5F00_54.036Z_2D00_log.txt

RE: AGPS with SUPL with MQTT_Simple example

Øyvind — Fri, 04 Jun 2021 09:33:53 GMT

Hello,

I've discussed the issue with some of my colleagues. First of all, the error -13 is not permission denied, it is from the SUPL library (nrf\ext\lib\bin\supl\include\supl_session.h)

#define LIBSUPL_TIMEOUT                     (-13)

In the the GPS struct gps_cfg, please try to remove priority = true, or set to false:

struct gps_config gps_cfg = {
            .nav_mode = GPS_NAV_MODE_PERIODIC,
            .power_mode = GPS_POWER_MODE_DISABLED,
            .timeout = 360,
            .interval = 360 +
                    30,
            .priority = true,
    };

And please increase the MQTT keepalive, which is default to 60 seconds in the MQTT library. This value depends on the MQTT broker you are using, i.e. AWS IoT allows a keepalive of maximum 1200 seconds. You could try e.g. 180 seconds:

CONFIG_MQTT_KEEPALIVE=180

Kind regards,
Øyvind

RE: AGPS with SUPL with MQTT_Simple example

Nahan_Trogn — Thu, 03 Jun 2021 10:44:11 GMT

This is my log file. I manually start AGPS by button, when seeing RRC Idle Event. I achieve 2 successes.devzone.nordicsemi.com/.../2021_2D00_06_2D00_02T14_5F00_24_5F00_18.010Z_2D00_log.txt

The Default AGPS example and GPS example work well. I combine AGPS to MQTT_Simple base on the AGPS example.

RE: AGPS with SUPL with MQTT_Simple example

Øyvind — Thu, 03 Jun 2021 10:21:35 GMT

[quote user="Nahan_Trogn"]Idle, then continue to wait 25-30 seconds, and start AGPS, sometimes SUPL success, many times fail.[/quote]

Can you provide some information on what is failing

[quote user="Nahan_Trogn"]My problem is I don't know when to do the first start for AGPS to obtain SUPL data.[/quote]

Does the default AGPS sample work?

Have you tried to start with e.g. AGPS sample and add MQTT to this?

RE: AGPS with SUPL with MQTT_Simple example

Nahan_Trogn — Thu, 03 Jun 2021 09:58:00 GMT

In my case, I want to use AGPS, so I still wait for RRC Idle? I try to start AGPS when RRC in Idle mode, but the same problem. I wait for RRC to announce Idle, then continue to wait 25-30 seconds, and start AGPS, sometimes SUPL success, many times fail.

My problem is I don't know when to do the first start for AGPS to obtain SUPL data.

I use nRF9160 GPS driver [experimental].

RE: AGPS with SUPL with MQTT_Simple example

Øyvind — Thu, 03 Jun 2021 09:39:41 GMT

Hello,

You can use e.g. AT+CSCON to check the signaling connection status to check mode parameter, either Idle or Connected. The former is what you will need to check.

Have a look at the LTE Link Controller (nrf\include\modem\lte_lc.h) and the GPS sample, for an example on how this is handled (nrf\samples\nrf9160\gps\src\main.c)

RE: AGPS with SUPL with MQTT_Simple example

Nahan_Trogn — Wed, 02 Jun 2021 12:36:40 GMT

Hi,

In start function, I success enable PSM mode, and receive feedback "PSM parameter update: TAU: 15000, Active time: 6". How to know my device is in PSM? Are there any events that I can check?

I see that, in PSM mode, there is sometimes RCC in connected mode, does this affect GPS? So I only need to check RCC whether in idle mode?

RE: AGPS with SUPL with MQTT_Simple example

Øyvind — Wed, 02 Jun 2021 11:35:36 GMT

Hello,

Error: -13 that you get, translates to

#define	EACCES 13	/* Permission denied */

The GPS receiver supports GPS L1 C/A reception. Operation is time multiplexed with LTE modem, and it is possible to obtain the GPS position either while the LTE is in RRC Idle mode or power saving mode (PSM), or when the LTE modem is completely deactivated.

Please make sure that your device is in PSM or deactivated before starting GPS.

Kind regards,
Øyvind