A-GPS using SUPL doesn't work

[Yusuke]

DK: v0.9.0
nrf: v1.2.0
supl fw: v0.5.2
modem fw: v1.2.0
OS: Windows10

I'm trying to use assited GPS in "gps" sample program, but it doesn't work. This is log. There is no comments about SUPL.

*** Booting Zephyr OS build v2.1.99-ncs1  ***
Staring GPS application
Socket created
Getting GPS data...
Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 0

Scanning [|] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 0

Scanning [/] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 1

Scanning [-] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 1

Scanning [\] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 2

Scanning [|] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 2

Scanning [/] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 3

Scanning [-] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 3

Scanning [\] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 4

Scanning [|] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 4

Scanning [/] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 5

Scanning [-] Tracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 5

Scanning [\]

prj.conf

CONFIG_BSD_LIBRARY=y
CONFIG_STDOUT_CONSOLE=y
CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_NEWLIB_LIBC=y
CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
CONFIG_AT_CMD=y
CONFIG_AT_NOTIF=y

# Enable SUPL client support
CONFIG_SUPL_CLIENT_LIB=y # Set y 

# Networking
CONFIG_NETWORKING=y
CONFIG_NET_SOCKETS_OFFLOAD=y
CONFIG_NET_SOCKETS=y
CONFIG_NET_SOCKETS_POSIX_NAMES=y
CONFIG_NET_SOCKETS_SOCKOPT_TLS=y

# Disable native network stack to save some memory
CONFIG_NET_NATIVE=n

# Main thread
CONFIG_HEAP_MEM_POOL_SIZE=2048
CONFIG_MAIN_STACK_SIZE=4096

In main.c,

supl_init function is executed successfully.
gps_data->data_id value is always 1 or 2 and it isn't set 3.

Any help?

[Håkon Alseth]

Hi,

 

It seems that the configuration has not been applied properly. After printing "Getting GPS data" it should fetch AGPS data if SUPL is enabled.

Could you try to re-import the gps project (with clean build folder) to see if this helps?

 

Kind regards,

Håkon

[Yusuke]

I can't get SUPL data even when I re-imported the project... I attached additional info below. Do you have any advice? Thank you in advance.

I'm using iBasis SIM

a-gps.zip

[Yusuke]

when I append these lines, I got an error. Any tip?

CONFIG_LTE_LINK_CONTROL=y
CONFIG_LTE_NETWORK_MODE_LTE_M_GPS=y

*** Booting Zephyr OS build v2.1.99-ncs1  ***
Staring GPS application
Failed to initialize modem

[Yusuke]

>failure to resolve the hostname usually indicates that the vendor does not provide DNS.

This means SIM Card vendor right? I'm using MVNO SIM card

[Håkon Alseth]

Hi,

 

Yusuke said:

This means SIM Card vendor right? I'm using MVNO SIM card

Yes, it might be that the network provider doesn't provide a DNS. 

 

Yusuke said:

when I append these lines, I got an error. Any tip?

This is because the application requires to set certain things before enabling the modem. By adding those settings, you are actually starting up the modem before entering the main function. If you need to change the XSYSTEMMODE, you can do this in gps/src/main.c file, at the top.

 

Does the AGPS procedure always fail with iBasis, or just "once in a while"?

 

Kind regards,

Håkon 

[Yusuke]

>Yes, it might be that the network provider doesn't provide a DNS. 

SIM vendor says SIMs can be used with Google DNS 8.8.8.8 and 8.8.4.4

>Does the AGPS procedure always fail with iBasis, or just "once in a while"?

it always fails

[Yusuke]

How can I set DNS manually?

I guess I need to fix something around this in supl_support.c

int open_supl_socket(void)
{
	int err;
	int proto;
	u16_t port;
	struct addrinfo *addr;
	struct addrinfo *info;

	proto = IPPROTO_TCP;
	port = htons(SUPL_SERVER_PORT);

	struct addrinfo hints = {
		.ai_family = AF_INET,
		.ai_socktype = SOCK_STREAM,
		.ai_protocol = proto,
		/* Either a valid,
		 * NULL-terminated access point name or NULL.
		 */
		.ai_canonname = NULL,
	};

	err = getaddrinfo(SUPL_SERVER, NULL, &hints, &info);
	if (err) {
		printk("Failed to resolve hostname %s on IPv4, errno: %d)\n",
			SUPL_SERVER, errno);
		return -1;
	}

[Håkon Alseth]

Hi Yusuke,

 

You can set the DNS manually by adding the lines posted in this thread:

https://devzone.nordicsemi.com/f/nordic-q-a/50029/nrf9160-modem-firmware-v1-0-0-setting-custom-dns-server/235419#235419

 

Note that this must be called before the lte link is established.

 

For the iBasis scenario, could you try to increase the CONFIG_MAIN_STACK_SIZE to see if this affects the behavior?

 

Kind regards,

Håkon

[LordLucan]

I was also interested in getting the supplementary data for GPS working.

However, be aware that some network vendors will whitelist only a few IPs. So it may be that you simply cannot connect to supl.google.com when on the LTE network. Of course if you have another IP connection on your hardware you should be fine.

Regards

[Yusuke]

I see. Thank you for your report.

I hope a Nordic original SUPL server will solve this issue

[Yusuke]

Hi Hakon,

it seems that I need to set an APN to device manually. How can I do that?

[Håkon Alseth]

Hi Yusuke,

 

The APN can be configured to be set on boot-up using the lte link controller "lte_lc" library, by setting these two configurations:

https://github.com/nrfconnect/sdk-nrf/blob/master/lib/lte_link_control/Kconfig#L97-L109

 

The above is helper-functions that eventually call this AT command to set the APN:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/packet_domain/cgdcont_set.html?cp=2_1_5_0_0

 

Kind regards,

Håkon