[LG Optimus 2x] echo_21:
Introduction

Note: this thread shall relaunch the topic that I first posted here on Feb. 19th 2015.

At least in 2013 GPS on LG P990 (aka Optimus 2x/Speed) was working at "maximum performance" under [MENTION=3605868]tonyp[/MENTION] 's CM10.2 . Maximum performance means:

GPS Fix inside buildings (not too far away from windows; not in the cellar) in less than 20 seconds

GPS Fix with 8-9 satellites inside buildings and 10-11 satellites outdoor

Without wifi and without SIM card (or with SIM but in air plane mode) GPS cold start fix after battery removal in less than 60 seconds

If you never observed this performance and don't believe me read these posts:

Witness [MENTION=5458952]breeno.net[/MENTION]:

http://xdaforums.com/showthread.php?p=47438823#post47438823

http://xdaforums.com/showthread.php?p=47448331#post47448331

http://xdaforums.com/showthread.php?p=47462987#post47462987

Witness [MENTION=4920940]sgspluss[/MENTION] http://xdaforums.com/showthread.php?p=47379987#post47379987

Witness [MENTION=4211084]tomsi91[/MENTION] http://xdaforums.com/showthread.php?p=47411198#post47411198

Witness [MENTION=5308871]FidiS[/MENTION] http://xdaforums.com/showthread.php?p=47415521#post47415521

Witness [MENTION=3046290]louiscypherbr[/MENTION] http://xdaforums.com/showthread.php?p=47403730#post47403730

Witness tonyp: PM in Feb. 2015

Witness echo_21: believe me, or not :)

Witness [MENTION=5160773]dev>null[/MENTION] http://xdaforums.com/showthread.php?p=58950812#post58950812

Reference [MENTION=3605868]tonyp[/MENTION] (see aknowledgement in http://xdaforums.com/showthread.php?p=47706978#post47706978 )

:crying: Unfortunately many P990 users (me included) nowadays suffer from poor GPS performance. It sometime takes 5-10 minutes for the first fix (TTFF). Some write that GPS doesn't fix at all.

So my main target is to restore exactly this maximum performance and nothing else. It bases on the long term orbit (lto) data technology.

I am not interested in any other assisted GPS features that require internet connection via Wifi or mobile data nor that require data from the telefony cells! I am further not interested in any other GPS tweaks that e.g. only should correct the P990 clock (like top ntp).

:cool: Even if not LTO technology please read this post if you want to get at least a great GPS performance boost from broadcom's LBS technology :cool:

Current knowledge

For each topic of the following list I have strong evidence for being true. I will attach it the next days. Anyway, you are invited to correct and/or complete the following list. But we need evidence!

/system/bin/glgps processes high level gps routines

/system/lib/hw/gps.tegra.so implements low level GPS routines that are called by /system/bin/glgps

/system/etc/gps_brcm_conf.xml is the one and only GPS configuration file

/system/ect/gps.conf is absolutely needles!

/data/gps/gldata.sto archives operational GPS data from glgps

the ROM shall periodically dowload /data/gps/lto.dat from here http://gllto.glpals.com/7day/v2/latest/lto2.dat at least once in 7 days

/data/gps/lto.dat contains long term orbit data enabling the Broadcom GPS chip to work with maximum performance

no other data file (like XTRA, SUPL, etc.) is required for maximum performance!

Edit 2015/04/27: logging by /system/bin/glgps to log files in /data/gps/log/ can be enabled by adding cLogEnableInitState="true" to the first <hal /> block

Reserved