nRF9160 A-GPS SUPL run error

[Harry Wei]

Hello:

I'm testing nrf9160's A-GPS function, and I find that an error of SUPL will be reported at runtime:

 *** Booting Zephyr OS build v2.1.99-ncs1-rc1  ***␍␊
[14:39:14:640] Staring GPS application␍␊
[14:39:14:640] Socket created␍␊
[14:39:14:649] Getting GPS data...␍␊
[14:39:14:649] <0x1b>[1;1H<0x1b>[2JTracking: 0 Using: 0 Unhealthy: 0␍␊
[14:39:14:653] Seconds since last fix 0␍␊
[14:39:14:656] ␍␊
[14:39:14:656] Scanning [|] <0x1b>[1;1H<0x1b>[2JTracking: 0 Using: 0 Unhealthy: 0␍␊
[14:39:15:160] Seconds since last fix 0␍␊
[14:39:15:167] ␍␊
[14:39:15:167] Scanning [/] <0x1b>[1;1H<0x1b>[2JNew AGPS data requested, contacting SUPL server, flags 59␍␊
[14:39:20:882] Established LTE link␍␊
[14:39:20:890] ip ddb0:37:: (3700b0dd) port 7275␍␊
[14:39:21:090] Starting SUPL session␍␍␊
[14:39:21:100] ULP encoding length: 38␍␊
[14:39:21:100] Bytes sent: 38␍␊
[14:39:21:350] Bytes received: 7␍␊
[14:39:21:359] ULP ossDecode fail 5␍␊
[14:39:21:359] SUPL error: 1␍␊
[14:39:21:359] ULP encoding length: 18␍␊
[14:39:21:359] Bytes sent: 18␍␊
[14:39:21:368] SUPL session internal resources released␍␊
[14:39:21:368] Done␍␊

I use master branch of the nrf  repository(nrf/samples/nrf9160/gps); the modem version is v1.1.1(mfw_nrf9160_1.1.1.zip);the SUPL client library  is nrf9160_libsupl-v0.5.1-c145bfb.zip.

I modified SUPL server and server port to local server and port:

#define SUPL_SERVER      "221.176.0.55"
#define SUPL_SERVER_PORT 7275

If I didn't modify SUPL server and server port to local server, dns fail(because we can't use google service in China).

so please give me some advices! Thanks

Best regards!

Harry

[Didrik Rokhaug]

Hi.

Could you take a modem trace of when the error occurs?

If you do not know how to take a modem trace, you can follow this guide: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/how-to-get-modem-trace-using-trace-collector-in-nrf-connect

Best regards,

Didrik

[Harry Wei]

nRF9160_DK_A-GPS.zip

Hi, Didrik:

modem version v1.1.1

nRF9160 DK version 0.8.5

See attachment for trace file(I captured 3 times)

Best regards,

Harry

[Didrik Rokhaug]

There seems to be something wrong with your modem trace.

It should be much bigger (the size grows to several hundreds of kilobytes quite quickly).

Could you try again?

[Harry Wei]

Hi, Didrik:

I've tried according to your suggestion, but the result is the same.

The DEMO(nrf/samples/nrf9160/gps)starts LTE only for a short time(a few seconds),after that, LTE is closed, so the modem trace size is smaller.

Best regards,

Harry

nRF9160_DK_A-GPS_1.zip

[Harry Wei]

Hi, Didrik:

Could you see find problems only from the log?

Best regards,

Harry

[Didrik Rokhaug]

No, it was empty as well.

I have tested taking a modem trace when running the A-GPS sample, and the size of my trace increased with several kilobytes per second.

I have created a modified sample that activates modem tracing automatically. All you have to do is to start capturing a trace, then program the modified sample (it already uses your modified SUPL server).

When testing my modified sample, I got the same error as you did. I have also requested help from the SDK team to identify the problem.

May I ask what SIM card you are using?

Also, I noticed that you give the SUPL server address as an IPv4 address, but it is resolved to an IPv6 address. Does your SUPL server support IPv6?

agps_trace_china.zip

[Harry Wei]

Hi, Didrik:

Thanks for your work.I will test your DEMO.

 I am using China Mobile Communications Group Co.,Ltd SIM(CMCC) ,and  I need to make sure if my SUPL server support  IPv6.

Best regards,

Harry

[Didrik Rokhaug]

Were you able to capture a modem trace?

The IPv6 address might just have been due to the way the sample prints the address.

Do you know what SUPL version your SUPL server is using?