nRF9160 DK + Asset Tracker v2, AWS A-GPS

[MostlyHardware]

Hello!

I am having some GPS problems with the Asset tracker v2 firmware. It can find satellites, but it doesn't track them nor do I get a GPS fix before the timeout occurs. I was thinking to enable A-GPS to speed up the fix, but since I am connecting it to my own AWS IoT instance it doesn't seem to download any A-GPS data. How can I modify the asset tracker firmware so that it downloads A-GPS properly?

Some other info:

• I have clear skies and open surroundings for the device
• If I run the GNSS firmware it gets a GPS fix within 30 seconds, so I am suspecting some kind of interference with the modem. iBasis supports PSM in my area but it doesn't seem to be activated if I read it out via modem commands.
• The original asset tracker firmware which connected to nRFcloud worked perfectly, so the device isn't faulty.

Thanks!

[MostlyHardware]

Håkon Alseth said:

Could you connect using at_client, and use the LTE Link Monitor (from nRF Connect for Desktop) to see the link details and share those here?

Issue:

AT+CEREG=5

AT+CFUN=1

AT+CFUN?

Hi Håkon,

I hope this formatting is ok for you. I masked the IP address and IMSIdentity.

AT+CEREG=5

 OK

AT+CFUN=1

 OK

AT+CFUN?

+CFUN: 1 

OK
AT+CGSN=1

+CGSN: "351516172719544"

 OK

AT+CGMI

Nordic Semiconductor ASA

 OK

AT+CGMM

nRF9160-SICA

 OK

AT+CGMR

mfw_nrf9160_1.3.2

 OK

AT+CEMODE?

+CEMODE: 2 

OK

AT%XCBAND=?

%XCBAND: (1,2,3,4,5,8,12,13,18,19,20,25,26,28,66) 

OK

AT+CMEE?

+CMEE: 1

 OK

AT+CNEC?

+CNEC: 24 

OK

AT+CGEREP?

+CGEREP: 1,0

 OK

AT+CIND=1,1,1 

OK

AT+CEREG=5 

OK

AT+CEREG?

+CEREG: 5,1,"2AFF","02024616",7,,,"11100000","11100000"

 OK

AT+COPS=3,2 

OK

AT+COPS?

+COPS: 0,2,"24008",7 

OK

AT%XCBAND

%XCBAND: 20 

OK

AT+CGDCONT?

+CGDCONT: 0,"IP","internet.telenor.se","xx.xx.xx.xx",0,0 

OK

AT+CGACT?

+CGACT: 0,1

 OK

AT%CESQ=1

 OK

AT+CESQ

+CESQ: 99,99,255,255,13,56 

OK

AT%XSIM=1

 OK

AT%XSIM?

%XSIM: 1

 OK

AT+CPIN?

+CPIN: READY

 OK

AT+CPINR="SIM PIN"

+CPINR: "SIM PIN",3 

OK

AT+CIMI

 xxxxx

[Håkon Alseth]

Hi,

 

Telenor in Norway by-default enables PSM in the LTE ATTACH, as seen here:

at+cereg=5                                                                                              
OK                                                                                                      
at+cfun=1                                                                                               
OK                                                                                                      
+CEREG: 2,"76C1","014ACE00",7                                                                           
+CEREG: 1,"76C1","014ACE00",7,,,"00001010","11000001"                                                   
at+cops?                                                                                                
+COPS: 0,2,"24201",7

 

You can try to manually request PSM via the AT+CPSMS command:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/nw_service/cpsms_set.html?cp=2_1_7_2_0

There's an example on requesting PSM in the end of the page.

 

CEREG should give you a notification after some seconds when/if that is enabled, or you can issue AT%XMONITOR to read the enabled values as well:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/nw_service/xmonitor_set.html?cp=2_1_7_11_0

 

Kind regards,

Håkon

[MostlyHardware]

Håkon Alseth said:

You can try to manually request PSM via the AT+CPSMS command:

I have sent the following commands:

AT+CPSMS=1,"","","10101010","00100001"

OK

AT%XMONITOR

%XMONITOR: 1,"","","24008","2AFF",7,20,"02024616",442,6400,60,28,"","11100000","11100000","01001001"

OK

Seems like it is not working?

[Håkon Alseth]

Hi,

 

Could you take a modem trace and share that with me?

You need to compile the at_client with this config symbol, as described here:

https://infocenter.nordicsemi.com/topic/ug_trace_collector/UG/trace_collector/enable_tracing.html?cp=10_3_3_3_1

 

Issue these commands in the LTE Link Monitor:

AT%XMODEMTRACE=1,2
AT+CEREG=5
AT+CPSMS=1,"","","00101010","00100001"
AT+CFUN=1
AT+CFUN?

 

Kind regards,

Håkon