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[Q] GPS lock problem after kk

OP koj012

30th January 2014, 06:52 PM   |  #11  
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Quote:
Originally Posted by ShadowLea

...
Nothing suprising about that. It uses the celltowers to triangulate by sending a data package, as opposed to attempting to connect to three satelites. If the network is fast enough (UMTS and above) it is much easier to get an accurate position. GPRS doesn't work all that well, nor does having 1 bar of signal on anything but LTE.
...

Actually original aGPS doesn't quite work that way at all - here is some info from some of the guys doing some of the Linux kernel drivers for aGPS devices (I can not guarantee it is 100% accurate but fits OK with other info that I have seen):

http://wiki.openmoko.org/wiki/Hardware:AGPS

And another thing to remember when testing GPS - after a successful GPS lock it is very likely that you will have a MUCH faster 2nd GPS lock for up to about 2 hours. So any such immediate 2nd lock should be see in the above context, also the lack of it
Last edited by xclub_101; 30th January 2014 at 06:54 PM.
1st February 2014, 03:10 AM   |  #12  
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Least this problem isn't just me. Always used to track my rides with Endomondo without a hitch but I went out for the first time since KitKat and I couldn't tell you how many times it dropped out on that 2 hour ride ... but it was alot
6th February 2014, 05:09 PM   |  #13  
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Quote:
Originally Posted by Xalies

Least this problem isn't just me. Always used to track my rides with Endomondo without a hitch but I went out for the first time since KitKat and I couldn't tell you how many times it dropped out on that 2 hour ride ... but it was alot

Seems to be a very common problem. Read somewhere that this is a software issue and there is a fix if the phone is rooted by flashing a patch on it. But I'm not about to root my phone and lose the warranty. SAMSUNG please release an update quickly that fixes this problem.
7th February 2014, 10:24 AM   |  #14  
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Quote:
Originally Posted by koj012

Seems to be a very common problem. Read somewhere that this is a software issue and there is a fix if the phone is rooted by flashing a patch on it. But I'm not about to root my phone and lose the warranty. SAMSUNG please release an update quickly that fixes this problem.

I am rooted (with knox 0x0 ) and I have looked into that patch - the one that I saw only sets a different AGPS server address and has minimal or no impact - actually I have a strong feeling that there is something in the CSC that overrides it, which explains why the AGPS server only improves things for me when connected only on mobile data and not over wifi.

IMHO that seems to be mostly a firmware / software driver issue - on my old S3 it looked like there was a lot more "caching" of the "GPS almanac" and slightly more pre-calculation of the "GPS ephemeris", possibly on the application CPU on the phone (which has humongous general-computing power compared with the CPU used inside the GPS circuit, which however is highly more specialized). On the Note 3 it seems to work in a "safer" approach in which older (than like 2 hours) GPS almanac data is considered inaccurate and so is the time otherwise used to pre-calculate GPS ephemeris (which time to be honest I have seen WILDLY inaccurate on some carriers, something like 27 seconds away; and of course if the time is not carrier-set the phone time can easily be tens of minutes away ).
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