[How-to][Hardware] Fix XA2 GNSS(GPS): Let's Try harder

General
#35

I also noticed, when in cold star (days after last fix, or far for last fix), that satellites in view increase qucikly (20 to 30 secondes?) to about 20 satellites, without anyone in use, but after 15 to 20 seconds more, with about 35 to 40 sat in view, fix is ok.
Remember that we are dealing here with GNSS, not only GPS.
So, satellites are from GPS, Galileo, Beidoo aand also Glonass constellations.

Maybe there is a first issue with antena ant top cap, but also with the use of several constellations.

It would be interested to see if satellites in use just after the fix are all in the same constellation.

#36

I believe they belong to several constellations.
Thanks to @dcaliste very interesting post in the big gps thread, we can see that.

#37

Hi @ric9k
Are you saying that because there are GPGSV and GLGSV string in NMEA output?

I will try that as soon as I got time for that.

#38

Yes. From what I read on wikipedia, this indicates to which constellation they belong.
Or, not?

#39

Yes. If it starts with:

  • GP = GPS
  • GL = GLONASS
  • GA = Galileo
  • GB = Beidou
  • GQ = QZSS regional GPS augmentation system (Japan)

GSV = satellites in view sentence

#40

I was quite happy with the overall navigation performance of my XA2. But I didn’t use navigation for a few weeks was impressed that the first fix then took me more than half an hour, the second one some fifteen minutes after which everything seems to work good again.

#41

Indeed, dirty contacts cause a long reception time of ephemeris which is needed for a cold start.
well…one theory between others…

After travelling 600km with no GNSS use, the GNSS receiver should be in a cold start state, theory says. Hence it’d need at least 12.5minutes to get a fix.
Mine needed less than 3 minutes IIRC. (GPSInfo says 21 seconds but sometimes stops counting before having a fix).
Anyways, too fast to fit with theory, so… I don’t know how it really works.

Try to open and clean yours! Who knows…

#42

I think the theory says that full ephemeris (for the whole GPS constellation) requires 12.5 minutes minimum (read without lossing frames on reception). But actually four satellites are enough to get your position, if their ephemeris are received first, then you can get a fix in less than 12.5 minutes. At least that’s my understanding of the system ; )

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#43

:man_facepalming:
Oh yes, so evident.
Thank you.
I thought the full ephemeris was necessary to even use some satellites.

#44

Ok, I’m done. I was that guy.
I am not anymore.

For some three years I always used by XA2 for navigation nearly on a daily basis and told everyone that there were no serious problems with navigation if one gave it al little time and patience. First problems showed up a few weeks ago:

Last weekend I went on a tour with my car for some 300 km (200 mls) in a rural area with sunny weather and nearly no clouds visible. Navigation had degraded so much, that I had to take a turn at least three times. Back in the city things did not actually improve.

So on Monday I decided that my XA2 would return to Android and live on as my Idiot-Phone with Lineage and MicoG. (My old Samsung S4 will retire eventually).

Yesterday I flashed my new Xperia 10 III, restored my backups and I am totally i m p r e s s e d how much better GPS/Glonass/Beidou work here. Nearly instant fixes even in closed rooms (near windows, though) and an overall good user experience.

I will report how navigation will work once the XA2 is back on the dark side of the force.

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#45

My impression is, GPS malfunction more depends of hardware than of SFOS. My last experiences with XA2 is more than 2,5 years ago, so no more relevant. But i can tell abt. X10 and Volla.

Time from switching GPS on & starting GPSInfo to valid position fix:

Sony: 50-60 sec.
Volla: 3-4 sec.

Conditions: rural area, in the house (small house), GPS not used before for a few weeks. SFOS 4.4.0.64 (X10 meanwhile updated to …68)

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#46

Better for me not to try a 10III then.
Considering the global situation, I try not to consume more goods than I really need but I don’t know if I could resist when trying one.

But I have to say my XA2 really works good after the hw repair. GNSS fix generally happens within the first minute. Sometimes within 2, rarely 3 minuges. Since approx 2 month now.
Especially cool since one month, I am travelling, no probs.

2 Likes
#47

Good idea @ric9k , mee too. Sometimes here in the forum there’s a used X10 ii or iii for sale.

#48

Your are right. As long as the fix works there is literally no reason to give up on a good XA2.
I will try the XA2 with Lineage, then maybe fix the antennas. I needed a replacement for the Samsung S4 anyway.

#49

I second that. Degradation came suddenly over a few weeks and my GPS did a great job over three years in many countries in Europe before.

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#50

On August, the first I did reflash my XA2 after navigation failed me pretty often and pretty fast after the first signs of degradation.

My new 10III does a much better job. No surprise.

But my old XA2 now with Lineage 19.1 and MindtheGAPPS suddenly appears to be navigating again with some success. I only tried inner city areas with good coverage and lots of networks but the combined navigation in Android with phone cell and WiFi triangulation sure takes a lot of the pain away.

I will do some tests in rural areas and see what happens there.

Edit:

And after a trip on the German Autobahn, where cell coverage is pretty good, navigation still works on the XA2, Lineage 19.1.

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#51

I think I can really testify now that my XA2 is fixed.
After I travelled this summer, the fix makes a huge difference in GNSS performance.

Before, it was a nightmare, now, it just works!

So, take your tools, go slowly, breath and think, and save your XA2!

2 Likes
#52

I found something.
Reading the log of the community meeting from Feb. 2nd, 2023, on a question @Cryx asked, @flypig mentioned two config files (10:09:00) and asked for feedback (10:09:13).

The config files are:
/etc/location/location.conf
and
/var/lib/location/location.conf

These files have identical content but are independent files and must be edited both.

On top there’s an entry
agreement_accepted=false

Here is my feedback:

Setting this variable to true:
agreement_accepted=true

fixes a lot of problems. Time to position fix (GPSInfo displays valid data) is now 1 sec on my Volla and a few (2-4) seconds on my Xperia 10, while in flight mode and no WLAN or other network connection, GPS settings is GPS only.

Before this tweak it was 10 sec on Volla and something between 5-30 min (or never) on the Xperia 10.

Maybe also an option for the XA2…

edit: Tested time to position fix again next day on Xperia 10. Result is, the same problems occuring as always, and I must confess this ‘hack’ attempt is worthless. So don’t waste your time on it.

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Community meeting on IRC 2nd February 2023
#53

Wow… If you found sth after so many tries of so many people for so long, you will deserve a krown!

Cannot test atm.
But I made the changes on XA2 and will report in case of improvement.

But what agrement is it about? Mls? Would have thought the change in the file would have been made when we agreed the Mozilla thing in settings…

Let’s try tomorrow.

#54

The gps.conf file was overwritten in the update to 4.5 so if you think you’re using suplpatcher and still waiting forever for a fix, just fix the file and reboot and make a backup this time. Tested on XA2.

Full instructions here:

Relevant bits:
/etc/gps.conf (Xperia X, …)
/system/vendor/etc/gps.conf (Xperia 10 II)
/vendor/etc/gps.conf (Xperia 10 III)

FOR unencrypted SUPL SUPPORT, set the following

SUPL_HOST=supl.google.com
SUPL_PORT=7276

for 4G devices

SUPL_VER=0x20000

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[Release notes] Struven ketju 4.5.0.19