XTRA data, why gps probably does not work ok

[Guest gravityz]

all you people probably know about the XTRA data file which is downloaded tohelp the aps to detect it's posible current location.

i noticed this file can only downloaded trough

Activesync

wifi

3G

you can not download it through gprs.

in google maps everything works ok for most people,

why

google maps detects it's possible location through GSM signal(searches for the nearest gsm antenna) and then uses agps to detect the exact location.

when you download the XTRA file through wifi or activesync HOW CAN IT POSSIBLE KNOW ITS CURRENT LOCATION.

this is probably why a lot of people think the gps is not working.

they do not have a good data connection(3G) so the correct XTRA data is not downloaded.

something is downloaded but the XTRA data file does not contain info about your location.

i tried it with gprs and in the netherlands that is not working(get an error that i can not download XTRA file)

can people confirm this

please respond if you have a 3g or other fast data connection and let us know how your gps works

also people with gprs can respond because maybee the gprs limitation is only on the provider site.

i know that once the gps knows were it is it gets a fix rather quickly

this data is not stored in the XTRA file because when you reset the omnia all data is gone

so second question.

were does the agps keeps his data?

[Guest 3shirts]

That doesn't sound right. On my N95 the agps connection was literally a few kb (including both directions) so why would it not do that over GPRS? I assume Xtra is the same thing but I could be wrong

EDIT: Just tested it and it got xtra data fine over gprs connection

Edited November 8, 2008 by 3shirts

[Guest ronaldb3]

gravityz-

When I manually use xtra the first bubble I get warns of possible extra charges -for gprs I think.

Then I get the phone buble that says "Connecting to GPRS"

And when I check Wireless Manager, the small bubble under the large Phone bubble changes from "On" to "Media Net" (AT&T for GPRS).

So what do you see that makes you think GPRS is not being used???

Ron...

[Guest jeffrey2000]

Well I'm from Holland too, I totally disabled the GPRS and xtra is off and it gets a fix in about 5/10 seconds with Igo. If I use Gippos (a great tool to chat from microsoft or google maps) it takes a bit longer to get a fixed location but this doesn't seem to work inside and uses my home wifi to get a quicker fix. I noticed that google maps first gives a global location with can be a bit off but gets better after a while (option: managed by windows).

Edited November 10, 2008 by jeffrey2000

[Guest drbf]

all you people probably know about the XTRA data file which is downloaded tohelp the aps to detect it's posible current location.

i noticed this file can only downloaded trough

Activesync

wifi

3G

you can not download it through gprs.

in google maps everything works ok for most people,

why

google maps detects it's possible location through GSM signal(searches for the nearest gsm antenna) and then uses agps to detect the exact location.

when you download the XTRA file through wifi or activesync HOW CAN IT POSSIBLE KNOW ITS CURRENT LOCATION.

this is probably why a lot of people think the gps is not working.

they do not have a good data connection(3G) so the correct XTRA data is not downloaded.

something is downloaded but the XTRA data file does not contain info about your location.

i tried it with gprs and in the netherlands that is not working(get an error that i can not download XTRA file)

can people confirm this

please respond if you have a 3g or other fast data connection and let us know how your gps works

also people with gprs can respond because maybee the gprs limitation is only on the provider site.

i know that once the gps knows were it is it gets a fix rather quickly

this data is not stored in the XTRA file because when you reset the omnia all data is gone

so second question.

were does the agps keeps his data?

GPRS working here in the USA to update the XTRA data file just fine..........

[Guest Reuben (MY)]

works in Asia as well.

[Guest gravityz]

well for starters it first tells me it is connecting thruogh gprs

after i have a connection and want to download the xtra file i get an error that no file is downloaded.

if i does the same through 3G it works

wifi and activesync also work but then i doubt that it will ge accurate data.

gravityz-

When I manually use xtra the first bubble I get warns of possible extra charges -for gprs I think.

Then I get the phone buble that says "Connecting to GPRS"

And when I check Wireless Manager, the small bubble under the large Phone bubble changes from "On" to "Media Net" (AT&T for GPRS).

So what do you see that makes you think GPRS is not being used???

Ron...

[Guest balles]

google maps detects it's possible location through GSM signal(searches for the nearest gsm antenna) and then uses agps to detect the exact location.

Maybe I am wrong, but what I understood is that XTRA file just contains satellite ephemerides, that is, the exact position of all satellites, so that the GPS does not need to precisely locate them because the work "is already performed by a server".

After this step, the classic positioning GPS algorithm starts by calculating time distances between the different satellite times.

when you download the XTRA file through wifi or activesync HOW CAN IT POSSIBLE KNOW ITS CURRENT LOCATION.

this is probably why a lot of people think the gps is not working.

Well, my server address for XTRA is set to : xtra1.gpsonextra.net. I changed it because my phone provider only lets me surf to 80, 8080 and 443, so the original address is blocked.

Can you verify yours at HKLM\ Software\Samsung\RIL\GPS?

Am I right or does XTRA contains something more?

[Guest gravityz]

interesting.

mine is set to test.agps.com:7275

Im tried your address xtra1.gpsonextra.net:80 and it seems way better.

first i tried without the :80

after that i changed it to xtra1.gpsonextra.net:80 , did a soft reset

after this i redownloaded the XTRA file

i had a fix within 15 secionds

before all the fix data was gone but now it seems to work better

will try it some more for a couple of days

so i thought that the agps used the location of the gsm phonelines but now it looks like it just uses timezones

problem with gps however is it needs to know were it is at so it knows which satellites should be visible in the sky above

since timezones are only vertical how dos it know where it is in a particular timezone.

Maybe I am wrong, but what I understood is that XTRA file just contains satellite ephemerides, that is, the exact position of all satellites, so that the GPS does not need to precisely locate them because the work "is already performed by a server".

After this step, the classic positioning GPS algorithm starts by calculating time distances between the different satellite times.

Well, my server address for XTRA is set to : xtra1.gpsonextra.net. I changed it because my phone provider only lets me surf to 80, 8080 and 443, so the original address is blocked.

Can you verify yours at HKLM\ Software\Samsung\RIL\GPS?

Am I right or does XTRA contains something more?

Edited November 14, 2008 by gravityz

[Guest ldbs]

i download mine with gprs in canada on the rogers network

and it works great. i disable it after my first download

i have even deleted the file, and used wifi and it works just as well.

[Guest balles]

interesting.

mine is set to test.agps.com:7275

i am gonnas try yours to see if it works better

how did you get that address?

so i thought that the agps used the location of the gsm phonelines but now it looks like it just uses timezones

problem with gps however is it needs to know were it is at so it knows which satellites should be visible in the sky above

since timezones are only vertical how dos it know where it is in a particular timezone.

In France you can use agps.orange.fr:7275 or geoloc2.sfr.fr:7275. As you say, I have realized (or I have the impression) that I have a constellation with fewer satellites than with my address (so just the visible ones). The address I gave contains the whole world satellites.

Having the whole world constellation should not be a problem because your GPS does not receive any data from these satellites, so the additional satellites are ignored.

Concerning where I found my address... I don't remember B) There is a good page here where you can find more information concerning the offline agps: http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=47602

You must have in mind that satellite ephemerides should be updated at least every three days.

PS: I think I was not clear enough with my previous explanation. Positionning is based on time comparison between satellites. Satellites send just a clock data, and this clock is synchronized between them. For instance, if you receive data from 3 satellites and it is the same time that you receive, you know that you are at the same distance from they three and you can estimate your position. If time is different between them, you can determine that you are closer to more recent time because there is lower propagation delays. This is roughly the GPS algorithm, based on the effect of signal propagation delays.

But you need to know the exact position of satellites first (the ephemerides) because they are not so stable for this kind of application. So either you identify their exact position (GPS without XTRA) and it will take more time to locate, either you receive their position by another way (XTRA).

[Guest Hendrickson]

We might all want to change our server as test.agps.com is offline for good!

[Guest bobobird]

My findings using iGo 832 for first fix, using xtras from these servers.

In all cases, gpsid log file is deleted / reboot / xtras loaded / reboot / test

xtra1.gpsonextra.net - ~30 secs. no sats display until about 28 secs.

agps.orange.fr:7275 - ~30 secs. no sats display until about 28 secs.

geoloc2.sfr.fr:7275 - ~45 secs. but sats display immediately

NO xtras - ~ 15 secs. sats display immediately, jump about a bit for 3-4 secs.

Am at a loss as to what this all means, but for me it seems that xtras disabled is the way to go.

[Guest gravityz]

i have similar results

first i thought deleting the files was bad because afterwards i did not receive anything

it turned out i neede to be in my car(outside)

every day when i turn on my phone, go in my car enable gpsproxy

after 4-5 seconds satellites start showing up.

mostly i have a fix in 30 secondes

before the satellites only showed up one at a time but now they all show all at once

it looks like the Xtra functionality in inverted

Xtra enables, satellites show up slow like the gps is really scanning for them

Xtra disabled and log setting deleted, satellites show up really fast

for now i stick with this solution

if anybody can solve the tomtom thing we do not need extra programs like gpsproxy that would be nice

My findings using iGo 832 for first fix, using xtras from these servers.

In all cases, gpsid log file is deleted / reboot / xtras loaded / reboot / test

xtra1.gpsonextra.net - ~30 secs. no sats display until about 28 secs.

agps.orange.fr:7275 - ~30 secs. no sats display until about 28 secs.

geoloc2.sfr.fr:7275 - ~45 secs. but sats display immediately

NO xtras - ~ 15 secs. sats display immediately, jump about a bit for 3-4 secs.

Am at a loss as to what this all means, but for me it seems that xtras disabled is the way to go.

[Guest balles]

I'm surprised with your results...

The fact that you stop XTRA, and as you guessed, should not improve the reception time. Have you suppressed the previous received XTRA file?

Keep in mind that whenever the XTRA file is downloaded it is stored in the root directory as xtra.bin file. This file is useful for 6 days and should be renewed every three days for better results.

I think that the Samsung GPS driver downloads systematically xtra data, so it takes XX additional seconds. If you have not suppressed the previous xtra.bin file, I would say that with your speed connection XX = 15 seconds :rolleyes:

Please, let us know.

PS: You should have stop the generation of GPS log file in order to improve GPS reception.

My findings using iGo 832 for first fix, using xtras from these servers.

In all cases, gpsid log file is deleted / reboot / xtras loaded / reboot / test

xtra1.gpsonextra.net - ~30 secs. no sats display until about 28 secs.

agps.orange.fr:7275 - ~30 secs. no sats display until about 28 secs.

geoloc2.sfr.fr:7275 - ~45 secs. but sats display immediately

NO xtras - ~ 15 secs. sats display immediately, jump about a bit for 3-4 secs.

Am at a loss as to what this all means, but for me it seems that xtras disabled is the way to go.

Edited December 11, 2008 by balles

[Guest jh787]

Have you tried typing in *#1472365# into their Omnia2?

It brings up some extra gps settings, some of which are similar to settings that can be reached in registry but some are unique.

The main one that was of interest to me was the start up mode of GPS.

Mine was set to cold start which meant that every time i started my tomtom it did so by deleting all previous data.

This meant i was on a cold start each and every time i used it which was why it took forever to lock sometimes.

I have now changed this setting to "hotstart" and my locks are instant.

There are various other settings that can be played with and tried out but this setting alone got rid of the only flaw i could find in the Omnia2.

[Guest jh787]

I compared the registry of my brothers htc (which has tomtom working)and my omnia i8000 and saw that among other htc specific settings one of the differences was that the intermediate driver had no buffer settings in registry.

I decided to back up my registry and delete both incoming and outgoing buffers and now i have an immediate signal and once locked it does not jump from one satellite to another, they are consistent blue bars.

I recommend that everybody try this but please back up your registry first.

Please see post 95 in the following thread for my registry settings which give me a very fast fix with excellent accuracy.

http://www.modaco.com/content-page/275659/...0/#entry1238381

Please provide some feedback and let others know if it works for you

Edited April 7, 2010 by jh787