GPS data acquisition time with SUPL assist is longer than expected

[Yusuke]

Dk 0.8.5 with external GPS antenna
modem FW: v1.1.1
nrf tag:  v1.2.0
supl: v0.5.1
OS: Windows10

Put supl folder to "\ncs\nrf\ext\lib\bin\supl"
* the path written in readme.rst in supl foder is wrong: \ncs\nrf\ext\bin\supl
Fix it.

I run "gps" sample program setting CONFIG_SUPL_CLIENT_LIB=y.

I expected quick gps data acquisition within a few seconds, but it takes 30~120 sec in the first acquisition.

Does it actually use SUPL data?

*** Booting Zephyr OS build v2.1.99-ncs1-rc2  ***
Staring GPS application
Socket created
Getting GPS data...
\x1B[1;1H\x1B[2JTracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 0

Scanning [|] \x1B[1;1H\x1B[2JTracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 0

Scanning [/] \x1B[1;1H\x1B[2JNew AGPS data requested, contacting SUPL server, flags 59
Established LTE link
ip adc2:4cc0:: (c04cc2ad) port 7276
Starting SUPL session
ULP encoding length: 38
Bytes sent: 38
Bytes received: 34
ULP ossDecode success, choice 3
SUPL response received
ULP encoding length: 57
Bytes sent: 57
Bytes received: 1024
ULP ossDecode more input 4
Bytes received: 1969
ULP ossDecode more input 4

Bytes received: 3065
ULP ossDecode success, choice 5
Injected AGPS data, flags: 1, size: 16
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72

Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 2, size: 72
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
Injected AGPS data, flags: 3, size: 32
No integrity data available
Injected AGPS data, flags: 4, size: 8
Injected AGPS data, flags: 6, size: 144
No location data available
Injected AGPS data, flags: 7, size: 16
MCC location info injected, MCC: 440
SUPL POS received
read again
Bytes received: 34
ULP ossDecode success, choice 6
SUPLEND:
	\x09Mask: 0

	\x09Status: 0
SUPL END received
SUPL session internal resources released
SUPL session finished
Done
\x1B[1;1H\x1B[2JTracking: 0 Using: 0 Unhealthy: 0
Seconds since last fix 15

[Martin Lesund]

Hi Yusuke,
Thank you for the feedback on the mistake in the library path, it has been reported internally.

(I have placed the SUPL files accordingly):

Please share the full output log when running the GPS sample, since it seem to be cut OFF before it Tracks any satellites.

Have you compared the time it takes to get GPS fix without the SUPL library enabled vs. not? (you should see a big improvement when using A-GPS)

Where have you placed the external GPS antenna, open space for best results? (make sure you put the physical GPS antenna switch (SW12) to select the external)

There have been some reports with customers having issues getting the data from the SUPL server in your area, we are looking into that. 

Best regards,
Martin L.

[Yusuke]

I showed the log above. Isn't it enough?

[Yusuke]

BTW, with some SIM cards, reading assisted data downloaded from SUPL server fails. At least it fails with Hologram SIM in Tokyo.

SUPL POS received
read again
read again
read error: -1
ULP ossDecode fail 5
SUPL error: 1

[Martin Lesund]

Awesome! 
I am glad to hear that it works.
It would make sense that there would come an update to the Asset tracker with A-GPS support, hopefully, it will come in the near future.

[Martin Lesund]

That is an interesting find.

Does the Hologram SIM work with regular samples? 
e.g. Asset Tracker etc.

It could be interesting to look in more depth about why this is happening.
If you could take a modem trace when this is happening.

[Yusuke]

I heard that AGPS uses SMS to get assisted data from SUPL server. If it's correct, you can't use AGPS with SIM which doesn't support SMS.

[Martin Lesund]

Hi Yusuke,

It gets the data over the LTE network, so a SIM card that does not support SMS should also work.

[Hoang]

Dear all, 

I couldnt get the position from AGPS, but I got the position form MCC:

MCC location info injected, MCC: 242
	Lat: 6407964 Lon: 715361
	Unc semiminor: 127
	Unc semimajor: 117
	Confidence: 85
	Orientation: 0

I dont understand which standard for "Lat: 6407964 Lon: 715361", how can I convert to Lat and Lon, which I can use to find my position by https://www.google.com/maps/

Can someone help`? Thanks a lots

BR

Hoang