Does GPS require an installed simcard?
#1
I know the modem is also the GPS receiver and doesn't do much as a modem until a simcard is present, but does the GPS portion require one be installed too for the separate satellite positioning?
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#2
I don't have a SIM card installed and the GPS was reasonably close to pinpointing my home. It's within 100 feet or so when Wifi is turned on. Much less accurate with it off. Currently the map software may leave a lot to be desired though. Probably depends upon distribution. I'm testing Mobian at the moment. Also, mobile internet may be required for what you want to do. E.g. The Gnome Maps application needs some form of Internet access for map data.
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#3
no, for what ever reason, the cell towers will let you use GPS with no SIM installed.

the caveat is that you won't have data to make use of the GPS information unless you somehow preload it, or use WiFi
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#4
GPS does not use cell towers. It talks directly to the satellite. That's why it takes so long if there is no AGPRS available (from a cell tower)

Also why if you use GPS outside of areas with a cell signal there is no tracking.

HTH
LF
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#5
(01-21-2021, 06:37 PM)mirror176 Wrote: I know the modem is also the GPS receiver and doesn't do much as a modem until a simcard is present, but does the GPS portion require one be installed too for the separate satellite positioning?
Let's take this logic:
Did you ever use a dedicated navigation system in a car (before they became build into cars)?
Did you need a SIM card to navigate?

I think you're getting 2 things mixed.
Maps are downloaded from the internet on the fly, which requires a SIM card (or a WiFi connection).
Car navigation devices download maps through a USB connection to a PC, so those things don't need internet.
Android and iOS both have an option to download maps in advance, so you don't need to waste data while travelling.
GPS connects to a satellite with or without SIM card.

Not sure how the Pinephone handles it, I never really had a reason to try it out yet.
I was in Kyoto with someone who has been there multiple times already, and I know all of Tokyo, Kawasaki, Chiba, Funabashi, and Saitama (the usual places I hang out at) and my own town from memory, I haven't been elsewhere since November.
母語は日本語ですが、英語も喋れます(ry
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#6
Has anyone tried it? While GPS itself doesn't require a SIM or mobile connectivity, some integrated chipsets won't let you use GPS if the SIM isn't present, for reasons not usually disclosed by the manufacturer. You probably need to disable ModemManager, connect to the serial interfaces and enable GPS manually, since ModemManager requires the SIM to be present before it will accept the gps enable command, even if the hardware doesn't, at least according to:
https://gitlab.freedesktop.org/mobile-br...issues/183
I don't know if oFono has a similar issue.

You can always fetch the AGPS data via wifi - it will significantly improve your chances of getting a GPS fix.
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#7
(01-25-2021, 05:11 PM)ryo Wrote:
(01-21-2021, 06:37 PM)mirror176 Wrote: I know the modem is also the GPS receiver and doesn't do much as a modem until a simcard is present, but does the GPS portion require one be installed too for the separate satellite positioning?
Let's take this logic:
Did you ever use a dedicated navigation system in a car (before they became build into cars)?
Did you need a SIM card to navigate?

I think you're getting 2 things mixed.

While it might sound weird, s/he is not asking something weird. While GPS has nothing to do with cell technology per se, the fact that it is integrated in a cell phone modem component, which pretty much turns itself off if there is no SIM card inserted, makes the question valid.

The analogy to a dedicated navigation system is not so useful here, because dedicated navigation systems do not have their GPS receiver integrated in a cell-phone modem with a binary blog behavior that is hard or impossible to control at time.
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#8
Could this be a regional (perhaps provider / type of sim card) issue?
I have two pinephones (1.2). One is running mobian+phosh, the other is running manjaro+phosh.
I toggle a SIM between those devices and can absolutely confirm, that mmcli refuses to enable location, if no sim is installed
In my case, after location is successfully enabled, I still have no location in gnome maps (wifi and mobile data working).
- does not work out of the box
- does not work with AT commands sent with mmcli
- does not work with AT commands sent with minicom

In January, I was able to get a location (out of the box) that was about 70 m away from my physical location.
Sorry, I can not say, which build I used at that time.

My location is Europe, Germany

Regards

btw: I observed, that every time, the device locks itself, the modem number changes.
Like a round robin, it is starting at 0, counting up, every time, the device locks.
Is this intended?
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#9
GPS without SIM works for me. I just removed the SIM and booted Mobian from eMMC with no SD present. It's not been updated in a while, but it's the one that has my agps script present and commands in the bash history so it was easier to try. WiFi was connected so I could still download the agps data.
sudo systemctl disable ModemManager.service
sudo systemctl stop ModemManager.service
./load_agps_data
picocom /dev/ttyUSB1

Unless I've forgotten about some config I've done to picocom at some point in the past, it should now show blocks of NMEA data updating every second - something like this block (sats being tracked but no fix yet):

$GPGSV,2,1,06,18,53,146,22,31,32,198,25,02,,,,04,10,291,,1*54
$GPGSV,2,2,06,05,15,045,,09,08,327,,1*65
$GPVTG,,T,,M,,N,,K,N*2C
$GPGSA,A,1,,,,,,,,,,,,,,,,*32
$GPGGA,,,,,,0,,,,,,,,*66
$GPRMC,,V,,,,,,,,,,N*53

After a few minutes indoors without a fix I took it outside, and got a fix within a couple of minutes I guess. I've seen much quicker fixes, but I've seen worse too so can't tell if I just got unlucky, or some change is making it harder to get a fix. When you get a fix you'll see time, lat and lon filled in in the GPGSA and GPRMC lines, among other changes.

I should point out that means the hardware works, not that ModemManager can use it yet.
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