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GPS performance

A

atko

Newbie
Hi guys,
I had a trouble with GPS connection and performance. There was lot of communication lost, long time posisioning etc. I try to experiment with gps.conf file. After some changes in gps.conf, my GPS performance is excelent.
There is a tip for you. I hope that help somebody of you.

1. Phone must be rooted.
2. Using RootExplorer you can edit file /system/etc/gps.conf
There was original version of gps.conf:

NTP_SERVER=xtra1.gpsonextra.net
XTRA_SERVER_1=http://xtra1.gpsonextra.net/xtra.bin
XTRA_SERVER_2=http://xtra2.gpsonextra.net/xtra.bin
XTRA_SERVER_3=http://xtra3.gpsonextra.net/xtra.bin

# DEBUG LEVELS: 0 - none, 1 - Error, 2 - Warning, 3 - Info
# 4 - Debug, 5 - Verbose
DEBUG_LEVEL = 3

# Intermediate position report, 1=enable, 0=disable
INTERMEDIATE_POS=0

# Accuracy threshold for intermediate positions
# less accurate positions are ignored, 0 for passing all positions
# ACCURACY_THRES=5000

################################
##### AGPS server settings #####
################################

# FOR SUPL SUPPORT, set the following
# SUPL_HOST=supl.host.com or IP
# SUPL_PORT=1234

# FOR C2K PDE SUPPORT, set the following
# C2K_HOST=c2k.pde.com or IP
# C2K_PORT=1234

################################
# EXTRA SETTINGS
################################

# RK_ID:RK_AGPS. DEP_RK_ID:NULL. AUT:weiwx@lenovo.com DATE:2010-11-27. START #
EVDO_C2K_HOST=10.199.22.165
EVDO_C2K_PORT=6066
# RK_ID:RK_AGPS. DEP_RK_ID:NULL. AUT:weiwx@lenovo.com DATE:2010-11-27. END #

# Wiper (wifi positioning), 1=enable, 0=disable
ENABLE_WIPER=0


I edit and change this line:
old:NTP_SERVER=xtra1.gpsonextra.net
new:NTP_SERVER=europe.pool.ntp.org
#or you can use different ntp servers near of you
#check pool.ntp.org: the internet cluster of ntp servers.

I add setting for AGPS
SUPL_HOST=supl.google.com
SUPL_PORT=7276

After this change my GPS working excelent.
Good luck ;)
 
NTP_SERVER=europe.pool.ntp.org
XTRA_SERVER_1=http://xtra1.gpsonextra.net/xtra.bin
XTRA_SERVER_2=http://xtra2.gpsonextra.net/xtra.bin
XTRA_SERVER_3=http://xtra3.gpsonextra.net/xtra.bin

# DEBUG LEVELS: 0 - none, 1 - Error, 2 - Warning, 3 - Info
# 4 - Debug, 5 - Verbose
DEBUG_LEVEL = 3

# Intermediate position report, 1=enable, 0=disable
INTERMEDIATE_POS=0

# Accuracy threshold for intermediate positions
# less accurate positions are ignored, 0 for passing all positions
# ACCURACY_THRES=5000

################################
##### AGPS server settings #####
################################

# FOR SUPL SUPPORT, set the following
# SUPL_HOST=supl.host.com or IP
# SUPL_PORT=1234

SUPL_HOST=supl.google.com
SUPL_PORT=7276

# FOR C2K PDE SUPPORT, set the following
# C2K_HOST=c2k.pde.com or IP
# C2K_PORT=1234

################################
# EXTRA SETTINGS
################################

# RK_ID:RK_AGPS. DEP_RK_ID:NULL. AUT:weiwx@lenovo.com DATE:2010-11-27. START #
EVDO_C2K_HOST=10.199.22.165
EVDO_C2K_PORT=6066
# RK_ID:RK_AGPS. DEP_RK_ID:NULL. AUT:weiwx@lenovo.com DATE:2010-11-27. END #

# Wiper (wifi positioning), 1=enable, 0=disable
ENABLE_WIPER=0
 
I was able to get location by 3G or wifi... now I have re-flashed the phone and It doesn't work. Any idea which is the option?
 
Sorry I don't know, but last 4 weaks I had isu with gps stability. phone found some satelites but after 1-2 minutes I lost gps signal. I don't know why where is problem.
 
after I edit gps.conf, if I turn off the gps, then turn back on it does not work at all.
Not even after replacing with the original file... i have to restart the phone.
if I set INTERMEDIATE_POS=1 I get location somewhere in the middle of Romania.
 
In the nicest way possible, 90% of gps.conf's found anywhere are BS. The bottom line is GPS implementation in phones and the software rushed out by most vendors just isn't up to par and most simply are broke. The above tweaks don't really tweak the GPS, but has your wifi/data use its location first to kickstart some info to an app to get it going. Then minutes later (provided you are outside with good weather), your GPS will eventually take over once it gets settled. (You will usually see this in the car when your Navigation gives your a "Rerouting" 100 feet down the road). SUPL/A-GPS rarely work in devices, and if you are lucky enough to have a phone from a vendor that actually puts forth an effort in development (HTC)...you device probably already works.

WHY: A-GPS/SUPL came into play when 911 wanted GPS info. GPS satellites download at 50b/s. So A-GPS was a concept that allowed devices to use their faster data connections to download a cache or kick-start file basically telling the GPS where exactly to look for the satellites.

With that said:
Changing the NTP server could always help, as the default one is in Canada and has to be overloaded.
The SUPL settings, I've never seen do anything, eventhough Google's SUPL server is functional.
ENABLE_WIPER flips on wifi location info so that will help...
but the one thing I've found that helps the most, is turning on intermediate positioning. Now as long as you are happy with the first 30 seconds to 1 minute of your location not being exact (it can vary 100 meters), you can get a "pseudo"-gps lock in 2 seconds flat on any device. I've found this startup innaccuracy is alot less stressful than the car honking behind you because you have no idea which way to turn because the Maps is sitting their flashing "Getting Location". But it's your call!
 
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