CSCON and GPS timer

RE: CSCON and GPS timer

Charlie — Thu, 18 Jul 2024 07:54:13 GMT

You are welcome! :-)

RE: CSCON and GPS timer

Alban THIERRY — Thu, 18 Jul 2024 07:51:34 GMT

Hi charlie,

Thank a lot for all your answer

Best regards,

Alban

RE: CSCON and GPS timer

Charlie — Thu, 18 Jul 2024 07:49:37 GMT

Each satellite transmits its own ephemeris data and common almanac data:

Ephemeris data - Provides information about the orbit of the satellite transmitting it. This data is valid for four hours and becomes inaccurate after that.
Almanac data - Provides coarse orbit and status information for each satellite in the constellation. Each satellite broadcasts almanac data for all satellites.

---- From Features of nRF91 Series (nordicsemi.com)

RE: CSCON and GPS timer

Alban THIERRY — Wed, 17 Jul 2024 11:27:55 GMT

Thank a lot,

did you know where I can find period of time from where it's valid ?

Best regard,

Alban

RE: CSCON and GPS timer

Charlie — Wed, 17 Jul 2024 11:16:38 GMT

Hi Alban,

It is a hot start. The downloaded GPS satellites data still valid for a period of time.

Best regards,

Charlie

RE: CSCON and GPS timer

Alban THIERRY — Wed, 17 Jul 2024 09:41:46 GMT

Hi Charlie,

Thanks for the answer 🙂

Just to be sure when I do :

AT#XGPS=0
AT+CFUN=21

do this reset delete the navigation data and need to do the cold start cold again or it will be some hot start ?

Best regards,

Alban

RE: CSCON and GPS timer

Charlie — Wed, 17 Jul 2024 09:07:25 GMT

Hi Alban,

[quote user="Alban THIERRY"]What sequence of AT command I need to sent to be able to use the LTE-M and the GPS in parallel?[/quote]

The sequence is quite clear, you get GPS fix when LTE modem either be completely deactivated or in RRC idle mode or Power Saving Mode (PSM) when using the GNSS receiver, then send messages though MQTT.

If you choose to deactivate LTE modem, the sequence can be the following.

AT+CEREG=5
AT%XSYSTEMMODE=1,0,1,0
AT+CFUN=31
AT#XGPS=1,0,0,290
Until GPS fixed received or timeout
AT#XGPS=0
AT+CFUN=21
AT#XMQTTCFG="MyMQTT-Client-ID",300,1
AT#XMQTTCON=1,"","","test.mosquitto.org",1883
AT#XMQTTPUB="nrf91/slm/mqtt/topic0","Test message with QoS 0",0,0
AT#XMQTTCON=0
Loop:
    AT+CFUN=0
    AT+CEREG=5
    AT+CFUN=31
    AT#XGPS=1,0,0,290
    Until GPS fixed received or timeout
    AT#XGPS=0
    AT+CFUN=21
    AT#XMQTTCFG="MyMQTT-Client-ID",300,1
    AT#XMQTTCON=1,"","","test.mosquitto.org",1883
    AT#XMQTTPUB="nrf91/slm/mqtt/topic0","Test message with QoS 0",0,0
    AT#XMQTTCON=0

If you choose to run GNSS during PSM state, you need to make sure your network operator support PSM feature as I explained, it is not just set by CPSMS command, the sequence can be the following.

AT+CEREG=5
AT%XSYSTEMMODE=1,0,1,0
AT+CPSMS=1,"","","10101010","00100001"
AT%XMODEMSLEEP=1,60000,60000
AT+CFUN=1
Rec:+CEREG: 1,"xxxxxxxxx","xxxxxxxxxxx",7,0,2,"00100001","10101010"
AT#XMQTTCFG="MyMQTT-Client-ID",300,1
AT#XMQTTCON=1,"","","test.mosquitto.org",1883
LOOP(should less than MQTT KEEP-Alive period):
    If Rec:%XMODEMSLEEP: 1,539975
        AT#XGPS=1,0,0,290
        AT#XMQTTPUB="nrf91/slm/mqtt/topic0","Test message with QoS 0",0,0

The application logic/sequence is of course decided by you, above is just a demonstration to show how to use the commands.

Best regards,

Charlie

RE: CSCON and GPS timer

Alban THIERRY — Tue, 16 Jul 2024 14:31:07 GMT

Thank for the answer, but I would to it in AT command using serial LTE modem firmware. In the future the master will receive some bluethoot message and push it also in MQTT.

What sequence of AT command I need to sent to be able to use the LTE-M and the GPS in parallel?

Best regards,

Alban

RE: CSCON and GPS timer

Charlie — Tue, 16 Jul 2024 14:05:48 GMT

This discussion may help:

(+) implementing GNSS sample code with MQTT sample code Error. - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)

RE: CSCON and GPS timer

Alban THIERRY — Tue, 16 Jul 2024 12:46:44 GMT

Hi Charlie,

To resume my project, I would like to have the GPS coordonate every 10min (for example) and send it in a MQTT.

Since the GPS and the LTE-M can't work together, I try to using CPSMS (to cut the LTE-M), but it don't seem to work.

What do you suggest ? What sequence of command I need to sent to be able to do this ?

Best regards,

Alban

RE: CSCON and GPS timer

Charlie — Tue, 16 Jul 2024 12:26:19 GMT

Hi Alban,

Kazi is not available temporarily. I will continue to help you on this ticket.

[quote user=""]I don't understand why but the GPS timeout after 580s instead of 290s[/quote]

This is properly a bug, but I need to do more test to verify, I will let you know when I figure out more information.

Just in case you did not realize, GNSS and LTE can not work at same time on nRF9160, you can refer to https://docs.nordicsemi.com/bundle/ncs-2.7.0/page/nrf/device_guides/nrf91/nrf91_features.html#concurrent_gnss_and_lte for details.

[quote user=""]I don't understand in the second CEREG response the Active-Time and the Periodic-TAU is not the same than the one I set with the CPSMS command. Did I configure something wrong ?[/quote]

The actual Active-Time and Periodic-TAU values are decided by the network, you can check the with AT%XMONITOR command or +CEREG notification.

+CEREG: 5,"E488","09343C10",7,,,"00011110","11100000" shows the network Periodic-TAU value is "11100000" which means PSM feature is deactivated on your network. You can check with your network operator to confirm.

[quote user=""]My ultimate goal is to reduce the power consumption and the consumption of data.[/quote]

This is quite general requirement for an IoT device, nRF91 is designed for this kind of application.

[quote user="Alban THIERRY"]

I understand for the roaming, when you say modem sleep notification, is just the LTE-M that turn off or also the GPS ?

What is the difference between this method and send AT+CFUN=31 ?

[/quote]

AT+CFUN=31 Activates GNSS without changing LTE. docs.nordicsemi.com/.../cfun_set.html

%XMODEMSLEEP set command subscribes and unsubscribes all types of modem sleep notifications. https://docs.nordicsemi.com/bundle/ref_at_commands/page/REF/at_commands/mob_termination_ctrl_status/xmodemsleep_set.html

Best regards,

Charlie

RE: CSCON and GPS timer

Alban THIERRY — Fri, 12 Jul 2024 06:56:47 GMT

Hi Kazi,

I understand for the roaming, when you say modem sleep notification, is just the LTE-M that turn off or also the GPS ?

What is the difference between this method and send AT+CFUN=31 ?

Best regards,

Alban

RE: CSCON and GPS timer

Kazi Afroza Sultana — Thu, 11 Jul 2024 11:48:32 GMT

Hello Alban,

When the device is roaming which can affect PSM, some networks treat roaming devices different in regard to PSM.

''Also I'm not sure how the CPSMS command work. I don't understand how the MQTT can wake up the modem part and ask for a synchronization''

You can use the proprietary %XMODEMSLEEP command to subscribe modem sleep notifications. Based on the %XMODEMSLEEP indications, the application can optimize its power efficiency by synchronizing its operations with the sleep and wake-up events of the modem and the radio activity and inactivity.

You can look at this link Modem sleep notification %XMODEMSLEEP (nordicsemi.com) about modem sleep notification.

Thanks.

Kazi