Unsatisfactory GPS reception on PinePhone?

[robin.com.au]

Hi I'm the latest victim of this GPS issue. Based on https://forum.pine64.org/showthread.php?tid=14114, I ran the following in order to get longitude and latitude.

Code:

sudo rc-service modemmanager stop # May or may not be necessary

echo at+qgps=1 | sudo atinout - /dev/EG25.MODEM - # turn on the GNSS
echo at+qgpsgnmea=\"gsv\" | sudo atinout - /dev/EG25.MODEM - # show the satellites tracked
echo at+qgpsgnmea=\"gga\" | sudo atinout - /dev/EG25.MODEM - # show the location if it is fixed
echo at+qgpsend | sudo atinout - /dev/EG25.MODEM -  # turn off the GNSS

And this is my output:

Code:

pine64-pinephone:~$ echo at+qgps=1 | sudo atinout - /dev/EG25.MODEM -

OK
pine64-pinephone:~$ echo at+qgpsgnmea=\"gsv\" | sudo atinout - /dev/EG25.MODEM -

+QGPSGNMEA: $GPGSV,4,1,16,02,00,116,,05,15,285,,06,,,,07,19,085,,1*58
+QGPSGNMEA: $GPGSV,4,2,16,08,,,,09,,,,11,,,,12,,,,1*67
+QGPSGNMEA: $GPGSV,4,3,16,13,56,223,,14,52,157,,15,20,223,,17,58,047,,1*6A
+QGPSGNMEA: $GPGSV,4,4,16,19,43,012,,20,08,320,,21,,,,22,67,201,,1*55
+QGPSGNMEA: $GLGSV,3,1,11,78,39,224,,66,14,002,,86,04,144,,77,31,149,,1*79
+QGPSGNMEA: $GLGSV,3,2,11,76,,,,79,07,268,,69,02,203,,88,18,040,,1*4C
+QGPSGNMEA: $GLGSV,3,3,11,87,25,097,,67,53,317,,68,42,232,,1*47

OK
pine64-pinephone:~$ echo at+qgpsgnmea=\"gga\" | sudo atinout - /dev/EG25.MODEM -

+QGPSGNMEA: $GPGGA,,,,,,0,,,,,,,,*66

OK
pine64-pinephone:~$ echo at+qgpsend | sudo atinout - /dev/EG25.MODEM -

OK
pine64-pinephone:~$

And this result is what I'm focusing on:

Code:

$GPGGA,,,,,,0,,,,,,,,*66

Which is lacking a bunch of information other than the 0 which means an 'invalid' quality indicator:

Code:

$GPGGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh

The interpretation of the 15 fields is the following,

1    = UTC of Position
2    = Latitude
3    = N or S
4    = Longitude
5    = E or W
6    = GPS quality indicator (0=invalid; 1=GPS fix; 2=Diff. GPS fix)
7    = Number of satellites in use [not those in view]
8    = Horizontal dilution of position
9    = Antenna altitude above/below mean sea level (geoid)
10  = Meters  (Antenna height unit)
11  = Geoidal separation (Diff. between WGS-84 earth ellipsoid and
      mean sea level.  -=geoid is below WGS-84 ellipsoid)
12  = Meters  (Units of geoidal separation)
13  = Age in seconds since last update from diff. reference station
14  = Diff. reference station ID#
15  = Checksum

I believe user 'sog8b' from page 1 had that exact "$GPGGA,,,,,,0,,,,,,,,*66" in the earlier post years ago, but he somehow solved it.

I just bought this Pine Beta Edition, and I ran JumpDrive to install postmarketos running sxmo. I bought it for the sole purpose of scripting GPS. I test it mainly via SSH and in a room with a window, and I did try putting the phone outside the house. I also started suspecting the problem is because the sim does not have a data plan.

There's just so many variables, is there a sure-fire way to determine whether it's a hardware, firmware, software, user issue?