Database Users

is it possible to calibrate the GPS?

HI
I'm having a problem with my GPS, it always shows me a location shifted like 250m from the place I am at that moment.
any idea how to solve it?
thanks!!

sirrick1 said:
HI
I'm having a problem with my GPS, it always shows me a location shifted like 250m from the place I am at that moment.
any idea how to solve it?
thanks!!
Click to expand...
Click to collapse
What software are you using? you may get a faster answer if you mention it

i dont think you can calibrate GPS..
you updated quickfix?

thanks for your answers, I'm using Garmin XT and google maps, then I don't think it is the software.
quickfix? sorry I don't know what is it, I will check now

ahh quickfix is the same as quickgps, yes I'm using it!

Does it just happen lately? Maybe hard resetting would help.

thanks but not really.
well I have my HD for already 6 month but I just start trying the GPS in the last 2 weeks, because I'm in China and was difficult to find a good GPS software for Asia, but I hard reset it couple of times since I start using it.

It might be a hardware issue. You may send it to a distributor center to check.

I was hoping it was not a hardware problem, because it always shows me like 250m to the south west, it's not a random problem.
any idea?
thanks!!

It's very difficult for the GPS "engine" itself to consistently report a position with such a fixed error.
I once saw a similar sort of error when I was using some GPS software which had the MAP DATUM set incorrectly.
Is it possible to change this setting on your software ?
Good luck,
- Steve

sirrick1 said:
thanks but not really.
well I have my HD for already 6 month but I just start trying the GPS in the last 2 weeks, because I'm in China and was difficult to find a good GPS software for Asia, but I hard reset it couple of times since I start using it.
Click to expand...
Click to collapse
Hi, sirrick1.
Nothing wrong with your GPS hardware/Software.
As required by Chinese goverment, all GPS map data should be added a deviation. ie. if you want to use a GPS coodirates that get from GPS hardware directly to locate where you are in map, you may find location is shifted.
Anyway, you can get more information from chinese gps forums.

litsen said:
Hi, sirrick1.
Nothing wrong with your GPS hardware/Software.
As required by Chinese goverment, all GPS map data should be added a deviation. ie. if you want to use a GPS coodirates that get from GPS hardware directly to locate where you are in map, you may find location is shifted.
Anyway, you can get more information from chinese gps forums.
Click to expand...
Click to collapse
i tot from history there was a air incident caused by purposely inaccurate GPS and the authorities ( not talking about china ) decide to not hamper the raw signals..
btw from what i know of GPS, you are caculating based from a few sats in space.. so is it possible in maths to get constant SW 250 results? not sure ... i am not a mathy.. anyone?

litsen said:
Hi, sirrick1.
Nothing wrong with your GPS hardware/Software.
As required by Chinese goverment, all GPS map data should be added a deviation. ie. if you want to use a GPS coodirates that get from GPS hardware directly to locate where you are in map, you may find location is shifted.
Anyway, you can get more information from chinese gps forums.
Click to expand...
Click to collapse
really? WOW!! I didn't know! I will check more from Chinese forums!! thanks!!!

leobox1 said:
btw from what i know of GPS, you are caculating based from a few sats in space.. so is it possible in maths to get constant SW 250 results? not sure ... i am not a mathy.. anyone?
Click to expand...
Click to collapse
The shift algorithm is a goverment secret, and the shift value is diffrent in one area from another.
So, it is hard to get/infer the exactly algorithm. So far as I know, the only succeful method to "correct" map coordinate is table look-up that is can get relative "real" values.

it's caused by the MAP it Self
not hardware or the software

May not be due to your GPS hardware.
I have the same problem with my MapKing Navi software, it's off by about 20m. I know it's the software problem, was the same on my iPaq previously. So you may want to find out if your software has the same problem on a device of a different brand.

in china the map are offset by 250m by government for unclear reason, on garmin you need to apply a patch to fix it, what's not clear it's google map, min is working well.

well I tried the patch, which is only a file (006B082300.bin) which must be copied to the folder containing the map, but the problem reminds!!
anyone has success on this?

I had similar problem on motorola a1000 running SmartcomGps, which uses maps in .ogf format. I have great maps made by army cartographers, calibrated precisely, and gps device kept missing position by 100 meters. I also thought that is army's stupid trick in case enemy obtain maps to be deliberately inaccurate. Tried recalibration, succeeded, but still not satisfied, kept googling for days and finally found the solution: on calibration, all maps are assigned with datum WGS84 by default. Changed it to Eastern Europe and bang! - device is locking position dead accurately.
Try this:
Start program, load map, then tap Map/Calibrate/Settings/Map Datum. Choose datum "South Asia" or "Hu-Tzu-Shan" or any other you might think is for your part of China. Try it, if it doesn't work properly then try some other one and do so untill you find proper one. Don't waste your time (and risk screwing something up) with patches, flashing different ROMs etc. Both your hardware and software are OK, just need correct setting.

HTC touch 3G GPS & wifi not working

--------------------------------------------------------------------------------
Hello every one ,
Am a new member to this and last week I bought (HTC touch 3G) phone online it came from china
New but I notice that the GPS & wifi not working good and by the way there is no quick GPS application It look deferent applications than normal also when I checked the serial number it said its not valid with www.HTC.com , The device information are
PDA version V03.04.00
PDA Build s0906020941(1.18.....)_BV
Stack version v02.42
Stack build May 16 2009
Radio version 1.3
Radio package 2.2
I need your help
Thanks in advance

It might be a fake! see-
http://forum.xda-developers.com/showthread.php?t=525336

Found 100% fix
goto http://www.mediafire.com/download.php?njyzllmlzmw download it no more orange unique just htc took me just 15 mins should work on the fack htc touch 3g's to

Re: GPS not turning on
kaly45 said:
--------------------------------------------------------------------------------
Hello every one ,
Am a new member to this and last week I bought (HTC touch 3G) phone online it came from china
New but I notice that the GPS & wifi not working good and by the way there is no quick GPS application It look deferent applications than normal also when I checked the serial number it said its not valid with www.HTC.com , The device information are
PDA version V03.04.00
PDA Build s0906020941(1.18.....)_BV
Stack version v02.42
Stack build May 16 2009
Radio version 1.3
Radio package 2.2
I need your help
Thanks in advance
Click to expand...
Click to collapse
Most PDA GPS's do not turn on automatically by themselves unless instructed or invoked by a software application. I have not looked carefully at my Jade clone's SIRF's specifications but most GPS under ideal situations can take as little as 42 seconds when warmed up to get four satellites to lock on to. Four satellites are necessary in most sytems are necessary for 3D satellite navigation (satnav or GPS).
What are ideal situations? Glad you asked. Basically, one of the most critical needs for a GPS is accurate time. This is the first item that must be sync'ed by satellites. To use a gross example, let's say your clock is off 60 minutes. In a car that could equate to roughly 60 miles. Satellites need accurate time because when they begin to sync, they will compute what satellites are available to sync with your GPS. Just like the sun, moon and stars are only in the sky at moving intervals of time, only a fixed amount of satellites are overhead at any given time.
Once your GPS begins to sync, ephemeris data (which satellites and the times they are overhead) is transmitted to your GPS. When combined with accurate time, the resolution of where your receiving GPS becomes easier.
The next critical issue is where does your GPS think it is. If the GPS was last turned on at the factory (testing), then it will store that location as its last known position. Guess what? If you're in Paris, France and your GPS was made in Malaysia, your last known position known now as initial positon to the satellites will tell them based upon time to use satellites in the Asian area to compute your satnav position. A GPS without a good initial position will make it difficult for satellites to accurately determine your location which could now takes a minimum of four minutes as long as ten minutes and maybe even hours.
Finally, where is your GPS physically located? In ideal conditions, it is outside with clear sky overhead in a stationary location. It's easier to shoot a sitting duck; a moving target or a GPS on the go complicates all the issues of time, location and signal acquisiton.
To help you, I recommend you download a small cab file that be used in your Today screen. It is aptly called "GPS Toggle". In essence, like a mechanic warming up your car prior to you driving it on a cold day, this plug-in "warms up" your GPS for you prior to needing it.
There is one thing you need to do to help your GPS - it is best for WM to manage it (a recommended feature from Microsoft). Go to the Settings tab, External GPS (why it is called that on my Settings tab is beyond me). Then click through the screens to have WM manage the GPS. On one tab you will asked to choose a Port from which all your programs will access data. You need to use an unused Port. I recommend Port 9 but that is up to you.
The reason for doing this is if WM manages the data, it will keep the GPS on and provide the resolved info to all applications. If the programs managed the GPS, they could selectively turn on and off the GPS and also block each other from using the GPS. You don't want that to happen. That is why MS recommends WM manage the data.
GPS toggle, when installed on your Today screen, will have an ON/OFF switch. When you turn it on, it will on the same line tell you how many satellites it has found and when it has sync'ed with them. When you see that four satellites are in the green (meaning your GPS is found ready for 3D satnav), then you can use satnav program of your choice.
The GPS uses battery power and supposedly is a big drain on smartphones. You want to turn it off and on only as necessary. Hope this helps (it's sticky stuff good info)!
GPS Toggle download link: http://www.freewarepocketpc.net/ppc-download-gps-toggle.html

Brookse567 said:
goto http://www.mediafire.com/download.php?njyzllmlzmw download it no more orange unique just htc took me just 15 mins should work on the fack htc touch 3g's to
Click to expand...
Click to collapse
Have tried to download - unable to open (as .php) - do I simply put the file in custom_ruu folder to then flash to the phone?
Thanks in anticipation

It might be a fake.
Open the Settings tab, go to "System" and look for "Device information". The CPU must be Qualcomm MSM 7225 and the full model name should be Touch 3G T3232. If not, it's a fake.

Thanks digsf.
Checked the phone and it would appear to be legit (just as well as it came direct from Orange UK)
It is frustrating that everyone else seems to be getting the roms to work, but for some reason i can't get them to do so - i must still be doing something wrong....

pmbb said:
Thanks digsf.
Checked the phone and it would appear to be legit (just as well as it came direct from Orange UK)
It is frustrating that everyone else seems to be getting the roms to work, but for some reason i can't get them to do so - i must still be doing something wrong....
Click to expand...
Click to collapse
You might be in the wrong thread. And although you probably have already visited these links and threads, I will recommend them to you:
http://forum.xda-developers.com/showthread.php?t=514406 Jade Flashing Guide for NOOBS
http://forum.xda-developers.com/showthread.php?t=483465 Jade / Touch 3G Hard-SPL Unlocker
And here is where you might get mileage from your post/question:
http://forum.xda-developers.com/showthread.php?t=534581 All jade questions & answers here pls
And this post:
http://forum.xda-developers.com/showpost.php?p=4336142&postcount=3
Good luck!

Cloned HTC Touch 3G
I went through the posts - I guess even I have landed up with a cloned HTC Touch 3G. Wonder what the drawbacks are. Somehow after a lot of tinkering I have been able to get my GPS to work (yes it has a built in GPS antenna) and it's accurate!
I set the hardware to COM 3, baud rate 4800
application to COM 0
In Google maps>options>GPS settings>manual settings (COM0 baud rate 4800)
IT WORKED!!
The WiFi can't be turned on with TouchFlo. Anybody has a solution to that?

[GPS/AGPS] REAL solution analysis thread (Jupiter Tweaks) - v006! - Froyo JI6

Here's that donate button you guys were looking for. >_>
https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=7ELH2CPLUZLQY
ANECDOTAL EVIDENCE IS NOT REAL EVIDENCE!!!
Get My Tracks from Google Market and post your GPS trip.
My first Froyo 2.2 test:
http://maps.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=108472444080796738089.000491a2c10ac25693114
Jupiter.XML
Jupiter.XML is not a Samsung specific file.
Jupiter mods
I've been modifying some information from the Jupiter XML to get different results. After installing a new jupiter.XML, got to LBSTestMode and select Delete GPS Data.
They can be installed by:
Code:
adb push jupiter.xml /system/etc/jupiter.xml
or (if permission denied)
adb push jupiter.xml /sdcard/jupiter.xml
adb shell
su
busybox cp /sdcard/jupiter.xml /system/etc/jupiter.xml
rm /sdcard/jupiter.xml
I made some changes to Jupiter (hopefully) enabled low noise amplification and remove a lag while trying to regain a hot fix.
View attachment Jupiter-v001.zip
Here's a v002 without ANY AGPS data. Because of a theory that AGPS is causing inaccuracy problems, I've disabled it completely. The fix will take longer, but maybe it'll be more accurate. With AGPS off, you won't get signal indoors. Remember that please and this is for the sake of testing.
AGPS doesn't have anything to do with accuracy. Stick with v001
Removed
You should also disable AGPS within Android
You can disable AGPS this way
Code:
adb shell
su
cd /dbdata/databases/com.android.providers.settings
sqlite3 settings.db
update secure set value="0" where name = "assisted_gps_enabled";
.quit
reboot
v003 has AGPS again. Make sure you enable AGPS in android provider settings (see above). I also switched the SUPL to supl.google.com:7576 instead of spirent. I changed the FrqPlan to match the Blackberry devices FrqPlan.
View attachment Jupiter-v003.zip
v004 is based on XWJP4 from a i9000 build.
I changed a lot. I made my changes to jupiter.xml (disabled the LNA for testing) and I'm using unstable 300ppb (even though I think ppb are meaningless since ppm are more important). It has LBS data enabled from this firmware. Also, I put the new drivers and forced SUPL to supl.google.com in both jupiter and gps.conf
pulled for more testing
v005 are tweaks from XWJP4. I couldn't get the new libgps.so to work on our Captivates (crashes on boot). gps.conf goes in (/system)/etc
View attachment Jupiter-v005.zip
v006 is JI6 compatible. JI6 (the Froyo build) uses the same GPS driver structure as i9000 XWJP4, so we might be able to swap files. This also means it's compatible with i9000 devices. This is mostly playing with SUPL to point to Google and remove a possible fix lag.
/system/etc/jupiter.xml
/system/etc/gps.conf
/data/gps/secgps.conf
View attachment Jupiter-v006.zip
Jupiter Research
It's a interface configuration file for GLGPS from Broadcom. If Samsung messed up, IT'S HERE
These are Samsung's settings (with OH7 OTA)
LogPriMask="LOG_DEBUG"
LogFacMask="LOG_GLLAPI | LOG_DEVIA | LOG_NMEA | LOG_RAWDATA | LOG_DEVMS | LOG_ASIC_IO | LOG_BBTEST | LOG_DEVET | LOG_MESM | LOG_DEVKF | LOG_DEVJG | LOG_DEVMR"
FrqPlan="FRQ_PLAN_26MHZ_2PPM_26MHZ_300PPB_UNSTABLE"
RfType="GL_RF_4751_DANUBE"
BrcmRFwildBase="0x1E2D6409"
BrcmRFclkDiv="21"
BrcmRFclkRefHz="26000000"
pps-enable="false"
pps-offset-ms="0"
pps-width-ns="100"
THIS IS WHAT WE SHOULD PLAY WITH!
I'm done some research and these are values for FrqPlan:
The TCXO has to be accurate +/- 2.0 ppm.
The number after FRQ_PLAN_ describes the type of TCXO used, for example,
FRQ_PLAN_13MHZ_2PPM is a 13MHz reference clock.
FRQ_PLAN_13MHZ_2PPM
FRQ_PLAN_16_8MHZ_2PPM
FRQ_PLAN_26MHZ_2PPM
FRQ_PLAN_10MHZ_2PPM_10MHZ_50PPB
FRQ_PLAN_20000_2PPM_13MHZ_50PPB
FRQ_PLAN_27456_2PPM_26MHZ_50PPB
FRQ_PLAN_33600_2PPM_26MHZ_50PPB
FRQ_PLAN_19200_2PPM_26MHZ_100PPB
RfType values:
GL_RF_PALS7
GL_RF_BARRACUDA
GL_RF_2075_LN22
GL_RF_2075_BRCM
GL_RF_PALS7_BRCM
GL_RF_BARRACUDA_BRCM
GL_RF_BARRACUDA_EXT_LNA
I found this info here:
http://openembed.com/files/pdk15_imx35__Linux_RM.pdf
Captivate Settings from OTA OH7:
Code:
I stripped everything else because we don't need it. We're not debugging. In fact, that might be a reason for the lag (all that unnecessary debugging).
This is the HTC Legend's XML file
Code:
See a difference? NO debugging and different FRQPlan (different chip anyway)
I FOUND SOMETHING WORTHWHILE!!!
Blackberry device that uses the same chip. Here are the settings for gl1
Code:
Blah blah blah! Re-education part
I think a lot of you are playing with options, not knowing what you're doing. I've written some GPS applications for WinMo (check my post history) and have taken a look at this issue. I'm currently working on a project that uses the GPS and Android phones. I negotiated a deal with AT&T to get 50 Samsung Captivates (@ $150 each) with 2GB/mo ($25/mo) for a client and I think I'm going to cancel that.
I don't think many of you understand what's going on with the phone or what AGPS does. AGPS is basically GPS support with cell towers. There are different levels of cell tower support.
MS-Based usually just uses the cell tower's location (not yours) to figure out where you are. This will allow you to go online, and get the cell tower number and find out it's GPS location. From there, the GPS using satellite charting data to find and keep a fix. GPS almanac data (says where the satellites are in the sky) can be supplied by the cell tower (the point of MS-Based), downloaded over the internet or downloaded from GPS signals (the last of the 3 being the slowest). Getting a fix without having any satellite data or positioning is known as a cold fix.
MS-Assisted does what you guys would already figure is happening. It uses the cell tower positioning and cell tower signal central to triangulate your position. In WinMo this would disable your data connection but it seems that's not the case in Android. Regardless it might slow down your internet. Obviously the accuracy here is poor.
SUPL just tells you the lat/long position of the cell towers so changing servers does nearly nothing. Google may have faster SUPL servers than spirent but the data should be the same. Once you have that data, it should be cached locally (but who knows, this is Samsung we're talking about.)
The problem is, technically speaking, the GPS should work even without AGPS. I have a couple of GPS devices with SIRFIII and it works beautifully, no AGPS needed. It should be able to download the almanac, ephemeris and time from the GPS satellites without any cell towers. That's how you know the issue isn't your settings.
Disable AGPS and you'll realize you have no options to play with. You're all playing with AGPS settings which aren't really hardware based GPS (and thus inaccurate). AGPS is not accurate. It was never meant to replace hardware GPS (which is why they put hardware GPS in phones). Hardware GPS has much more accuracy but the fact is, hardware GPS is NOT working on the Samsung Captivate. That's the baseline problem. Forget your AGPS settings. AGPS should only help you with almanac data and getting faster fixes but after that it should be running on standalone hardware and only fall back to the inaccurate AGPS when you lose a clear view of the sky (like when you're in a tunnel).
I notice little issue when I'm standing still. It's when I'm moving that the accuracy dies. With further investigation, it seems the GPS literally stops updating the location after a couple of seconds. You don't notice if you're standing still since you're in the same spot, but when you're driving you'll see it. The GPS freezes for about 20 to 30 seconds.
The question is: Why is it not working?
Here are my hypotheses.
1) There's a function running that borks the GPS and makes the GPS driver crash or lag. The GPS driver quietly reboots and then it gets a fix. This could be the reason why, after disabling and enabling GPS, it grabs a hot-started fix of a location it was struggling to get before. You manually reset the GPS driver. I've tested it with Google Maps/Navigation. The GPS doesn't move for 30 seconds. It freezes, but when I close (disable GPS) and open the app (enable GPS) it gets a hot started fix in 5 seconds. Had I not disabled and enabled the GPS, it would have lagged there. This could be a software issue.
2) The GPS isn't using the almanac data. The almanac data says where the GPS satellites are now and where they will be. The GPS uses this to track. If this isn't used, it needs to get a fix again every so often.
3) Cell towers are actually messing you up because their times are desynchronized or almanac data is outdated. (and we all would love to blame AT&T)
As for my project, I'm ready to change my order from 50 Captivates to 50 Xperia X10 phone. The X10 actually has a WORKING GPS (meaning my app works fine and isn't the cause). I have both phones that AT&T gave me to develop my application. I wis

Thank you for the info. I am eagerly awaiting a true fix

makes sense, let us know of your future findings

I just want to say this is an excellent post and very informative. Thanks for writing it. Unfortunately, I'm seriously debating returning my Captivate over this whole fiasco. The OTA hotfix that's pushing out today does nothing to fix this issue and I some how doubt this will be resolved any time soon.

There are two test ROMS that were leaked, JH2 and JH3, that already have GPS logging enabled by default. We've been turning it off since the data isn't useful to us and it fills up the phone's storage quickly. Would those logs be useful to you?

I have a Captivate, so I don't need the logs really. What are your experiences with Dynamic Accuracy off? I feel like that could be the issue. I know the GPS disables after 120 seconds with Dynamic Accuracy off, but when it does work, how well does it work for you guys?
Also, is the GPS issue for ALL Galaxy S devices? (Vibrant/Captivate/i9000)

I just got my captivate so i havent been around long, but i know for sure it affects all the US versions of the Galaxy S series (Fascinate, epic 4g, captivate, vibrant), im not sure about the European i9000

It affects all Galaxy S phones regardless where you bought them. And the issue is with BroadCom (the GPS chip maker). There is a faulty driver and/or faulty chip firmware. From what I gather, BroadCOM gave Samsung the updated driver at the end of the August which our latest JH7 probably doesn't have.

faspalma said:
I just want to say this is an excellent post and very informative. Thanks for writing it. Unfortunately, I'm seriously debating returning my Captivate over this whole fiasco. The OTA hotfix that's pushing out today does nothing to fix this issue and I some how doubt this will be resolved any time soon.
Click to expand...
Click to collapse
According to Engadget, the latest update being pushed by AT&T "fixes" the gps issues: http://www.engadget.com/2010/09/22/samsung-captivate-gets-gps-fix-other-galaxy-s-versions-wait-pat/

compuguy1088 said:
According to Engadget, the latest update being pushed by AT&T "fixes" the gps issues: http://www.engadget.com/2010/09/22/samsung-captivate-gets-gps-fix-other-galaxy-s-versions-wait-pat/
Click to expand...
Click to collapse
Engadget is full of it.

foxbat121 said:
Engadget is full of it.
Click to expand...
Click to collapse
I think it is more that samsung "is full of it", because they are stating the gps is fixed. Engadget is just relaying what Samsung is saying....

Wasn't the source released for the captivate kernel? I would love to see the GPS source code
Sent from my SAMSUNG-SGH-I897 using XDA App

CLShortFuse said:
Wasn't the source released for the captivate kernel? I would love to see the GPS source code
Sent from my SAMSUNG-SGH-I897 using XDA App
Click to expand...
Click to collapse
GPS and most all of the drivers are not part of the source release.

Can we recompile the driver, does anybody know?
This is the source code for Nokia's driver for the same chip.
http://www.mail-archive.com/[email protected]/msg03733.html
But I don't think they use NMEA

Ok I hear what you are saying, I never messed with the settings and claimed that it was fixed. I am under the impression that my gps is working and always was but with the new jh7 firmware (ota version) it definitely works better, I had the samsung-firmwares.com release and it made no difference but designgears rooted decided version of thee ota release made a difference. What settings need to be changed to disable all network assisted location to test if I'm actually getting a gps fix without agps?
Sent from my SAMSUNG-SGH-I897 using Tapatalk

Dani897 said:
Ok I hear what you are saying, I never messed with the settings and claimed that it was fixed. I am under the impression that my gps is working and always was but with the new jh7 firmware (ota version) it definitely works better, I had the samsung-firmwares.com release and it made no difference but designgears rooted decided version of thee ota release made a difference. What settings need to be changed to disable all network assisted location to test if I'm actually getting a gps fix without agps?
Sent from my SAMSUNG-SGH-I897 using Tapatalk
Click to expand...
Click to collapse
Network assist is not a problem. There is no need to disable it.
Just take a test drive using Google Navigation. Ignore the fact that it always seems to be dead on your position (because all navigation software snap you to the nearst road). Instead, pay close attention to:
1. Whether or not you see a blue circle surrounding your position. If you do see that, your GPS has failed at that time and the size of the circle is the estimated inaccuracy of the GPS. You need to be patient because blue circle comes and goes randomly.
2. Pay attetion to certain landmarks like bridges, overpasses and intersections. And compare that to your position on the map to see if you experience lags.
3. The navigation software snaps you to the wrong road nearby even though you didn't see the blue circle.
In my personally experience, all three showed up randomly. I have no problem getting a quick lock at all.

foxbat121 said:
Network assist is not a problem. There is no need to disable it.
Just take a test drive using Google Navigation. Ignore the fact that it always seems to be dead on your position (because all navigation software snap you to the nearst road). Instead, pay close attention to:
1. Whether or not you see a blue circle surrounding your position. If you do see that, your GPS has failed at that time and the size of the circle is the estimated inaccuracy of the GPS. You need to be patient because blue circle comes and goes randomly.
2. Pay attetion to certain landmarks like bridges, overpasses and intersections. And compare that to your position on the map to see if you experience lags.
3. The navigation software snaps you to the wrong road nearby even though you didn't see the blue circle.
In my personally experience, all three showed up randomly. I have no problem getting a quick lock at all.
Click to expand...
Click to collapse
This has been my experience too...and while Cog 2.1 has made it better, I still experience these same problems.

I changed the first post and hope to make this a community effort.

The problem seems to be position estimation. When you take a sharp turn, the GPS position will keep going "expecting" you to follow the same path. After a few seconds, the GPS position will slowly return back to your real position.
If we could just remove position estimation / interpolation, we might see improvement.
You can see what I am talking about in my post here:
http://forum.xda-developers.com/showpost.php?p=8295858&postcount=2

Thank you ShortFuse.
This is the most truly helpful GPS thread in a while. I hope we can get to the bottom of this soon.
Everyone needs to contribute to this thread!

[Q] What is GPS config file for if I'm using offline GPS?

Hi there.
I need some one to teach me or explain to me, why we are using GPS config file.As long as I'm using offline GPS. I know it is for time sync and location accuracy. but I do not use data mobile. so how the time sync coming from NTP_SERVER=xxxxxx.pool.ntp.org??? .
thanks

Is it so difficult to be answered ??

gps.conf
I assume you are referring to the gps.conf file?!
From what I understand:
This is the list of online servers that the phone connects to to help with A-GPS since the HD2 doesn't natively support A-GPS.
This file can be modified dependant on your country and will limit the search to only the satellites available in the sky above you which CAN speed up the process of finding a lock.
Check out this thread for more info: http://forum.xda-developers.com/showthread.php?t=953630
Hope this helps!
BTW: If you only use offline GPS then this file doesn't matter to you since it can't connect to the online servers anyway!

deano309,
Your explaination is correct, if you are using offline mode, then your chances for gaining a lock becomes harder, because then you would be no different then a standalone unit, and if you see most standalone units take some time.
This difference is if you have a data plan, or if you have a wifi in your home, or area, by using the gps.conf (whether it be mine or the generic), the idea here is to get the gps to at least get a lock and know where it is, its suppose to help with re-locks, but this is only good (the information downloaded) for 7 days. Because our HD2's dont have native support in our drivers for AGPS, the file (Especially mine) has extensive commands to reduce the time for locks to occur by downloading that information thru wifi, and because there is a bit more involved with our HD2's there is a app also that when run that info is downloaded to the phone, and my file references it so you wont wait 3 to 5 mins or longer.
And thanks deano309 for the re-direct

fruity info
Yes, I'm referring to the gps.conf file .
Thanks deano309,AngelDeath for your fruitful info.

GPS is slow to lock on CM7.2-RC0. AGPS data is never downloaded.

I am using the latest incarnation of CM7.2-RC0 for the Aria. The GPS is very slow to lock if not used for a while or if manually reset using a GPS app. It will always lock eventually but requires about two to five minutes as it slowly aquires each satellite, locking after getting a fix on the fifth or sixth satellite. It is behaving as if it is doing a cold-start every time.
I have found that the AGPS data (xtra.bin) is never downloaded. I can see on my DNS server that the Aria never attempts to resolve any of the XTRA_SERVER names. Because of this, there is no way that xtra.bin file can ever be downloaded.
As a test, I reset the GPS using the "GPS Status" app and then restarted the phone. After it reboots, I can see a DNS query for the NTP_SERVER but no DNS queries for any of the XTRA_SERVERs. When I perform a manual download within the "GPS Status" app, a popup message immediately says "GPS assistance data downloaded" but I don't see how that is really possible since I never see a DNS request to resolve the XTRA_SERVER names.
If someone familar with the GPS code can take a look and see what is causing this behavior, that would be great. I think once the AGPS data is actually downloaded, the locks should be fast.
This GPS issue is the only major problem that I have come across with CM7.2.
-John

This issue is already known. The current version of the GPS libs in the CM repo are not working correctly, although functional. However, you can flash different versions of the GPS libs over your current ROM to fix the issues you are having.
The flashable zips are at the bottom of this post: http://forum.xda-developers.com/showpost.php?p=19106745&postcount=3688
liberty-cm-htc-stock-gps-signed.zip - original HTC drivers
liberty-cm-reverted-src-gps-signed.zip - older CM drivers from before they were messed up
liberty-cm-current-src-gps-signed.zip - current CM drivers

I knew about reverting to the older GPS libs. It's just that I've never seen any specifics on why the current CM7 GPS libs are not functioning correctly and thought I'd bring a data point to the discussion.
-John

My understanding was that someone submitted a fix to the repo to get GPS working properly on another device (I don't know which device), but although it fixes a problem on that device it created one on the Aria (and possibly others). Not sure on the timespan for if/when this will be corrected.

drumist said:
My understanding was that someone submitted a fix to the repo to get GPS working properly on another device (I don't know which device), but although it fixes a problem on that device it created one on the Aria (and possibly others). Not sure on the timespan for if/when this will be corrected.
Click to expand...
Click to collapse
that device was the supersonic (evo4g). doesn't look like it'll ever be fixed.