Librem 5 GPS/Location Tracking

Hardware Librem 5
61

It gives a bunch of data like this:

$GNGSA,A,1,,,,,,,,,,,,,99.0,99.0,99.0*1E
$GNGSA,A,1,,,,,,,,,,,,,99.0,99.0,99.0*1E
$GPGSV,3,1,11,01,77,077,,07,65,227,,30,52,292,,21,50,043,*75
$GPGSV,3,2,11,17,32,277,,22,28,121,,14,27,322,,03,21,131,*75
$GPGSV,3,3,11,08,20,048,,19,10,257,,09,06,203,,,,,*48
$GLGSV,1,1,02,87,41,012,,81,27,233,,,,,,,,,*60
$GPGLL,2256.33128,N,11351.74301,E,144745.000,V,N*48
$PSTMCPU,25.46,-1,49*4A
$GPRMC,144746.000,V,2256.33128,N,11351.74301,E,0.0,0.0,281121,,,N*75
$GPGGA,144746.000,2256.33128,N,11351.74301,E,0,00,99.0,031.00,M,0.0,M,,*65
$GPVTG,0.0,T,,M,0.0,N,0.0,K,N*02
62

The GSV lines are lacking the value which I inserted as ss:

$GPGSV,3,1,11,01,77,077,ss,07,65,227,ss,30,52,292,ss,21,50,043,*

which should be a two digit value between 00 and 99 and measures the signal/noise ratio. Without having them above 20++ for some minutes for some satellites, there will not be a fix.

63

@guru is correct. If that dump is from inside that is expected, please try the dump outside > 12 minutes.

The fact that the module is showing satellites is good, either it means the module has downloaded at least a partial almanac or you’ve uploaded an almanac to the module.

64

15 minutes outside, here’s a tail of the GPPSV:

$GPGSV,3,3,11,02,12,249,,01,11,042,,09,06,145,,,,,*4F
$GPGSV,3,1,11,14,81,157,,06,51,273,,17,49,008,,19,39,331,*70
$GPGSV,3,2,11,03,27,049,,22,20,044,,30,19,199,,11,18,244,*70
$GPGSV,3,3,11,02,12,249,,01,11,042,,09,06,145,,,,,*4F
$GPGSV,3,1,11,14,81,157,,06,51,273,,17,49,008,,19,39,331,*70
$GPGSV,3,2,11,03,27,049,,22,20,044,,30,19,199,,11,18,244,*70
$GPGSV,3,3,11,02,12,249,,01,11,042,,09,06,145,,,,,*4F
$GPGSV,3,1,11,14,81,157,,06,51,273,,17,49,008,,19,39,331,*70
$GPGSV,3,2,11,03,27,049,,22,20,044,,30,19,199,,11,18,244,*70
$GPGSV,3,3,11,02,12,249,,01,11,042,,09,06,145,,,,,*4F

It still has a few blank values in the commas. Does this mean the GPS is not working correctly?

Was in a open area and there wasn’t a cloud in the sky

65

I do not see any ss value between the commas.

66

There’s no SNR values in there so it’s not seeing any satellites. I’d contact support@puri.sm .

1 Like
67

I tried to get a fix on my L5, but I also do not see any ss values when I do:
socat unix-client:/var/run/gnss_share.sock - | grep -ai --line-buffered gsv

Here some output that I see:

$GPGSV,3,1,09,16,64,308,,27,48,175,,26,47,021,,31,36,071,*73
$GPGSV,3,2,09,04,35,320,,08,22,197,,03,23,258,,22,19,235,*74
$GPGSV,3,3,09,32,15,147,,,,,,,,,,,,,*47
$GLGSV,1,1,03,87,28,117,,86,16,051,,88,13,158,,,,,*57

I had the L5 outside for roughly 30 minutes, and for more than half a day close to the a window at the top of my house. The sky is cloudy nowadays here in the Netherlands. When the L5 was outside the number of satellites increased IIRC.

In the /var/cache/gnss_share/ directory, I only have a recent almanac.txt that I did not put there myself. It seems to update every day.

Should there also automatically appear an ephemeris.txt ?

# ls -l /var/cache/gnss_share/  
total 8  
-rw-r--r-- 1 root root 4464 Nov 30 08:57 almanac.txt

@steve: Did you contact Purism support? If so, what was their response?

68

My GPS does work (it takes some time to get a fix, but then I can use pure maps to navigate) but for me no ephemeris.txt file is created (while almanac is)

1 Like
69

I own two L5 devices, one does not see ss values and does not get a fix. The other, which sees ss values gets a fix even with cloudy sky in less than 2 minutes. It has also the two files ephemeris.txt and almanac.txt.

There are statements here in the forum that the reason could be a bad grounded antenna of the GNSS receiver chip. View this post: Librem 5 GPS/Location Tracking

3 Likes
70

Mm interesting… I’m using gnss_share --version : 0.3, is yours the same?

edit: found updates on the git repo, I’ll try to rebuild it

71

apt search gnss gives

...
gnss-share/byzantium, now 0.3-0pureos2 all [installed]
An app for sharing GNSS location data
72

Ok it seems like I built it myself, I just installed it from the repo (when it was still written in python, now it has been rewritten in go). I see that the service is automatically enabled, I’ll wait some time to see if the file appears

73

Does pure maps report the correct speed for you? Mine always report 4km/h

74

I’m using the app Maps and was told that this uses geoclue and this in turn not GPS. What is ‘pure maps’?

75

apt search pure-maps

It’s a navigation program, I think it’s using geoclue (which with gnss-share should use GPS)

76

geoclue does not interface directly to the gnss device. gnss-share will feed gnss coordinates to geoclue

Both Maps and pure-maps will get their data from geoclue.

77

I have, no response yet,
I’ll let you know when I get something.

1 Like
78

I have here a screenshot of Maps. The L5 have had a fix in this moment and my real position was in front of the building number 14 where a small cocktail glass is shown. Maps showed my position some 20 meters more to the east.

2021-11-26-163646
2021-11-26-163646720×1440 163 KB

79

The accuracy of that fix looks more like a wifi AP fix than a GNSS fix. A GNSS fix should be a 3M circle or less.

2 Likes
80

I did:

# gnss_share --version
warning: trio-serial not found, some drivers may not work correctly
version: 0.3

Is the warning trio-serial not found, some drivers may not work correctly relevant?