Very strange behavior of Location

General
#1

recently with my XA2 Ultra running 4.6.0.13
trying to get a fix GPSInfo gave a position with the usual horizontal accuracy of 9000 m
the trouble was that this position was about 4° in longitude to the east of my actual position which at the given latitude is around 360 km off to the east
in the same time opening OSM Scout i could see on the map a green dot located at my actual position
and as i was traveling at some speed i could see the dot moving
after a few hours (as is mostly the case) GPSInfo decided to give the actual position

at the same time a Fairphone 2 running SFOS 3.3 behaved as it should after around a minute to get the fix
and a very cheap Android device did that in a few seconds

the 3 devices were on Device only mode, the Fairphone and the android device did not have a SIM card

what can explain this strange and unreliable behavior?

will the 10IV and 10V behave as it should?

#2

If you search for “XA2 GPS” or similar you will find a couple of threads dealing with the fact location is rather wonky in XA2 in particular. And some attempts to improve it.

Support and featurefulness of unreleased software (SFOS on 10IV and 10V) can only be speculated on.

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#3

Yeah, XA2 can have some problems with GPS.
IIRC, Android can help itself with Wifi and Bluetooth to find it’s position.

This conjunction can show a big difference when comparing SFOS with Android regarding positioning.

However, all in all, some hardware fixes showed good results to me.

Here is one of the threads @nephros was probably talking about.
It shows you how you can clean and fix bad GPS signal transmission into your XA2.

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#4

@nephros

would you preorder and by a car from a vendor who tells you “i do not know whether the wheels are included”?

@ric9k
thanks for all the technical links, i can the see the astronomy expert you are in these

your solution seems to me well beyond my DIY skills, maybe some help from a better skilled fellow

do you believe Android uses some GPS assistance while there is:
no SIM card in the phone;
WIFI is turned off;
Use GPS only, Device only, is turned on?

#5

Would you ask this a car community forum rather than the manufacturer and expect to get an authoritative answer, for a model that hasn’t even launched yet?

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#6

Yes if the phone has been online before. GPS assistance data are in cache.
On my XA2 withe LineageOS, which was online and turned off one week ago, I’ve just started it offline and GPSTest app sees 25 satellites and locks on 7 satellites in 71 seconds. Then I’ve cleared the assistance data: no satellites detected in more than 5 minutes.

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#7

@nephros
i understand your point and my questions was purposefully ambiguous!
however 10IV and 10V are far from being new and if there is any hardware issue it should be known by the time
what is amazing, to me at least, is the lack of answer or statement from the Jolla team to this [multiple] type of issues

i also have trouble to really understand what in SFOS is made by Jolla and what is made by the community a link to some explanation would be welcomed

@phklrz
what do you mean by
“Then I’ve cleared the assistance data”
how this can be done
the adventure i tell before happened 400 km away from the last time i used the Android device and the other devices as well

#8

Maybe there is a forum around SFOS. Try to search and read carefully. There is no official support for the help function.

It’s more like buying a car from vendor A who cannot tell you if the car would still work if you put the complete drivetrain from a small car customizer B in it.

#9

Try to calibrate the compass, it should be really help the GPS to locate your position.
Usually when my XA2 is looking for my position for many minutes (hours :confused:), re-calibrating compass 4~5 times with CSD Tools is enough to get back a functional GPS.

#10

@mkz
i do not see the relation between the measurement of (nature created) magnetic field and (man made) GPS

nevertheless i have installed from Jolla store
Compass (by lpotter) gives crazy headings and i cannot see the way to calibrate it
Orienteering Compass (bu jussivuorisalmi) heading always 0 whatever i do with calibration
Sail Compass (by PeterParker) same heading as Compass and i cannot see the way to calibrate it

any hint about this?
what are CSD Tools?

#11

Settings->System->About Product->Build and tap few times.
Such behaviour is “normal” and expected in phones like XA2 or X. Accuracy 9000m means that you got fix from MLS only. GPS is heavily dependent on hardware. I have tested Xperia X and X10II simultanously and while X10II is getting fix very fast, Xperia X is struggling for a long time, particulary when there are a lot of buildings, trees, mountains and/or heavy clouds.

#12

I don’t know myself, it’s just my experience. Maybe, the GPS is disoriented by contractionary informations between satellites and compass ?

#13

In my case, GPS was -relatively- faster on the XperiaX than the XA2.

#14

MLS don’t need any connexion to return a position ?

#15

It does not if set offline. MLS only checks id’s of cell towers against local database.