[Q] aGPS question - Galaxy S I9000 General

Hi
Does aGPS require you to have a cellular data connection in order for it to work? Or will it work with any internet connection (eg. using my laptop's connection through wifi)? I'm asking because I don't have a data plan (yet), and my phone has locked only _once_ since I bought it a month or so ago. I've tried switching to MS based in LbsTestmode, changing the supl server to supl-google-com and supl-nokia-com (can't post links yet).
The one time it did lock was when I was testing the GPS without an internet connection, and I entered a WiFi covered area and it suddenly locked (5-10m accuracy). It wasn't WiFi-based positioning because it was my laptop's WiFi hotspot. And I was using the default settings at that time (www-spirent-lcs-com, Standalone mode). Since then I've tried different combinations of settings but it hasn't ever locked.
Another question: What's the difference between MS based and MS assisted modes?
My phone is an I9000 Galaxy S.

ssj4Gogeta1 said:
Hi
Does aGPS require you to have a cellular data connection in order for it to work? Or will it work with any internet connection (eg. using my laptop's connection through wifi)? I'm asking because I don't have a data plan (yet), and my phone has locked only _once_ since I bought it a month or so ago. I've tried switching to MS based in LbsTestmode, changing the supl server to supl-google-com and supl-nokia-com (can't post links yet).
The one time it did lock was when I was testing the GPS without an internet connection, and I entered a WiFi covered area and it suddenly locked (5-10m accuracy). It wasn't WiFi-based positioning because it was my laptop's WiFi hotspot. And I was using the default settings at that time (www-spirent-lcs-com, Standalone mode). Since then I've tried different combinations of settings but it hasn't ever locked.
Another question: What's the difference between MS based and MS assisted modes?
My phone is an I9000 Galaxy S.
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Click to collapse
Correct me if i am wrong, but as i know aGPS doesn´t need any Data Connection to make the triangulation between the GSM Antennas. So no need for Internet Connection to use aGPS.

TMReuffurth said:
Correct me if i am wrong, but as i know aGPS doesn´t need any Data Connection to make the triangulation between the GSM Antennas. So no need for Internet Connection to use aGPS.
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Click to collapse
AFAIK aGPS is different from cellular triangulation. It refers to downloading satellite information from a server for a quicker fix.

ssj4Gogeta1 said:
AFAIK aGPS is different from cellular triangulation. It refers to downloading satellite information from a server for a quicker fix.
Click to expand...
Click to collapse
I thought it would make a triangulation between the next availabe antennas in range and get over a dedicated channel (not data channel as mentioned above) localisation informations. Because my Nokia N80 had aGPS but not real GPS and in the manual they said something about this triangulation.
But of course i know the download of the actual satelite coordenates from my Touch HD in Windows Mobile with a dedicated App. Just thougth it is something diferent.

TMReuffurth said:
I thought it would make a triangulation between the next availabe antennas in range and get over a dedicated channel (not data channel as mentioned above) localisation informations. Because my Nokia N80 had aGPS but not real GPS and in the manual they said something about this triangulation.
But of course i know the download of the actual satelite coordenates from my Touch HD in Windows Mobile with a dedicated App. Just thougth it is something diferent.
Click to expand...
Click to collapse
aGPS is a technology that downloads satellite data from agps servers at realtime (that is the time you are using the GPS): WIKI article
I guess that the app you are refering to, the one you used on the HTC, is Quick GPS. This program doesn't download satellite postition data in realtime but once in a while. (I believe the data are vallid for 48h) With Quick GPS one can still enjoy the features of aGPS while one hasn't a data connection with a aGPS server.
The Galaxy S GPS (BCM4751) seems to have both, aGPS and a sort of Quick GPS. Only the last is called LTO by broadcom. (see: http://www.broadcom.com/press/release.php?id=s443754 about BCM4571 specs and see here about LTO.

aGPS uses cell tower triangulation, and information from a server, in addition to satellite radio signals, to quickly assist in determining the coordinates of a phone's location. Since cell tower sites are precisely surveyed, they are a reliable source for locational data. A data connection is required. All modern cell phones, at least here in the United States, are required to have aGPS service for use in locating a phone by emergency responders. This is a part of the E911 and is required by FCC mandate. Data is used in tracking down the phone, but it happens behind the scenes and is paid for by fees charged to cellular users on their bills for E911 compliance.
On phones that allow the user to make use of the aGPS chip, there will generally be a setting that allows you to set for E911 use only, or for what is commonly referred to as "location based services." On my Android phones, there are actually two settings, both found in Location & Security Settings. One allows for location based upon use of wireless networks, and the other allowing a fix via GPS satellites. Even with any location based services turned off, emergency responders can still find the phone. The difference being that you cannot use it.
While it is technically possible for you to use your phone's aGPS without a data connection, your chances of getting a signal are sketchy, and your chances of getting a really accurate signal are, under most circumstances, slim to none. Much of the computational work in determining your location is done by the assistance server, and guess how that information moves to and from your phone? Yep, you guessed it, data!
GPS signals sent from satellites are simply radio signals, and your local pop music radio station probably sends its signals with more force. As they are radio signals, they have to contend with everything a radio signal has to deal with, and a large percentage of that is man-made. Signals confusingly bounce off of buildings, are weakened by passing through walls and foliage, or can even be absorbed in some cases by different materials.
Some aGPS chips cannot function as stand alone GPS, and will not work at all without a data connection.
Try this, turn off your cellular radio. Make sure that your WiFi is also off. Now, fire up Google Maps and ask it to start navigation. How did it work?

appelflap said:
I guess that the app you are refering to, the one you used on the HTC, is Quick GPS. This program doesn't download satellite postition data in realtime but once in a while. (I believe the data are vallid for 48h) With Quick GPS one can still enjoy the features of aGPS while one hasn't a data connection with a aGPS server.
.
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Yeah, that i was talking about. Didn´t know this all I love this forum, you always learn more and more.

rasmith3530 said:
Try this, turn off your cellular radio. Make sure that your WiFi is also off. Now, fire up Google Maps and ask it to start navigation. How did it work?
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Click to collapse
Well, using Google Maps would not be a valid test, of course, since you need data connection to download the local map anyway. If you want to test whether data connection is requires by aGPS, you need to use an offline GPS application.

Thank you for your guys replies.
@rasmith3530: So can that data be downloaded over wifi? (My common sense says yes, just trying to confirm.) If it can, then aGPS isn't working for me at all. I see at max 2-3 satellites in LbsTestMode, without a lock on any of them.

No one said aGPS is working on SGS. They are broken and no fixes yet.

foxbat121 said:
No one said aGPS is working on SGS. They are broken and no fixes yet.
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Click to collapse
I think you're right. The fact that there are no ephemeris and almanac data recorded for satellites let me think that it may be the case that with a certain informed guess aGPS and the advertised LTO function doesn't work on none of the firmwares.

Other people seem to have locking/accuracy problems, they can at least see those satellites. Mine normally shows 0 or 1, so I thought maybe I'm doing something wrong.

ssj4Gogeta1 said:
Other people seem to have locking/accuracy problems, they can at least see those satellites. Mine normally shows 0 or 1, so I thought maybe I'm doing something wrong.
Click to expand...
Click to collapse
In JM1-JG5, I had that issue (couldn't lock onto anything). Switching to JM5 fixed that..

Related

Geolocation does NOT work with cellid only on 3G

I'm trying to figure out if anyone else is having this problem.
Got my G1 on the 21st. been playing with a few things and the laundry list of UI annoyances is getting longer by the minute.
but overall quite impressed. Here's a weird one.
Google Maps (on G1 of course) cannot locate my phone - at all - with wifi OFF and gps OFF.
I am in a 3G zone. Google Maps on my HTC Touch worked fine (EDGE only of course)
So I looked around and found a reference somewhere stating that cellid geolocation does NOT work in 3G areas.
Is this true of all 3G phones?? If so it's very strange - because I like to keep 3G on but when I am indoors or for that matter when I want to save battery I turn off GPS and wifi.
So why the hell would they not be able to geolocate by cellid?
I tested it on my G1 and it's true - as soon as you turn off 3G (Settings->Wireless Controls->Mobile Networks) then cellid Geolocation works fine.
Just thought people might want to know and I'm curious if anyone else has the same problem.
Nick
I heard from a network engineer that all of the 3G hardware was rapid deployed and configured to minimum specs which happened to NOT include enabling aGPS. It was either an oversight or a timesaver. This will be fixed, it is a known issue. All the techs are still in the middle of the initial deployment and rapid expansion before the end of the quarter.
I HOPE to god Tmo can stop the ATT commercials that brag about the fastest network in the US after this quarter.
that only kind of makes sense...
I mean sure - it's all new etc...
but the point is that the network is not doing the a bit of the aGPS - google is.
Google does a lookup of the cellid in its database - and presumably does not have any information on the new cellids.....YET.
I just find that weird - I am in the metropolitan LA area and you would think with all the hoopla of this launch and the financial might of google they could have gotten it together by now - I mean these towers didn't go up yesterday...
Nick
syrusfrost said:
I heard from a network engineer that all of the 3G hardware was rapid deployed and configured to minimum specs which happened to NOT include enabling aGPS. It was either an oversight or a timesaver. This will be fixed, it is a known issue. All the techs are still in the middle of the initial deployment and rapid expansion before the end of the quarter.
I HOPE to god Tmo can stop the ATT commercials that brag about the fastest network in the US after this quarter.
Click to expand...
Click to collapse
nickybee said:
Google does a lookup of the cellid in its database - and presumably does not have any information on the new cellids.....YET.
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Click to collapse
erm, is that how aGPS works on the G1? That's stupid. I was under the impression that it worked like normal aGPS... I.E. -
Phone: Where am I?
Tower: You are @ 33.12345/32.12345 accuracy 2000 meters
Tower: GPS sattelites G51, T85, R14 are 3 strongest
Phone: Fed GPS data to GPS radio, warm start for 10 sec lock as opposed to over a minute for a cold start lock.
And I am also under the impression that alot of the 3G hardware wasn't configured with the appropriate data (position with est of accuracy based on closest towers and affinity and the 3 strongest GPS signals for that area). The issue was noticed and any new hardware should be fine. Problems will be resolved as the expansion portion of the project begins and all of the areas are revisited.
Where did you get your info nickybee?
aad4321 said:
agps works fine with me on 3G....
also under settings...security and location.... if you look under "use wireless networks" it says with that turned on, it uses wifi and cell towers for location. I would imagine with this off, it will not geolocate through towers...
Click to expand...
Click to collapse
yes that was turned on on my G1 of course.
and no it still doesn't work.
nick
hey syrus - I didn't mean aGPS - I was just referring to the (a) part of the GPS.
i.e. there is no Phone saying "Where am I"
it goes
GMaps application: "What's my cell id?"
Phone: "It's ABC1"
GMaps application: "Hey Google dbase - where's cellid ABC1"
Google: "ABC1 is at 33.12345/32.12345 accuracy 2000 meters"
As to where I get my information from it's out of my ass
I accept that I could be totally wrong - but I assume that google does not go to the carriers for cellid information - it just drives around with the mobile vans and captures GPS data for Wifi and cellid simultaneously. Since the towers are quite new - their data has not been captured yet
Nick
syrusfrost said:
erm, is that how aGPS works on the G1? That's stupid. I was under the impression that it worked like normal aGPS... I.E. -
Phone: Where am I?
Tower: You are @ 33.12345/32.12345 accuracy 2000 meters
Tower: GPS sattelites G51, T85, R14 are 3 strongest
Phone: Fed GPS data to GPS radio, warm start for 10 sec lock as opposed to over a minute for a cold start lock.
And I am also under the impression that alot of the 3G hardware wasn't configured with the appropriate data (position with est of accuracy based on closest towers and affinity and the 3 strongest GPS signals for that area). The issue was noticed and any new hardware should be fine. Problems will be resolved as the expansion portion of the project begins and all of the areas are revisited.
Where did you get your info nickybee?
Click to expand...
Click to collapse
i never used the built in gpa, so far.
I use my bluetooth keychain gps. had it from my old excalibur.
works great
nickybee said:
GMaps application: "What's my cell id?"
Phone: "It's ABC1"
GMaps application: "Hey Google dbase - where's cellid ABC1"
Google: "ABC1 is at 33.12345/32.12345 accuracy 2000 meters"
Click to expand...
Click to collapse
Erm, you know now that I look at it Google is implementing SOMETHING new, I don't know how far they are taking it. Traditional aGPS has been around for a long time now, Google was never involved. I believe that at this point, with this version of Android things are still working the way they always have.
But! Did you notice the setting also indicates that the phone can find your location by wifi stations? I BET google receiving GPS data from users while they are connected to WIFI networks.
And then there's things like this below... ahh
http://arstechnica.com/news.ars/post/20071116-its-official-google-planning-700mhz-bid.html
Who knows, but I think as far as cell tower based aGPS is concerned android sticks with the basics. It's one data packet sent to the tower, and one back, rather than setting up a connection making a database query and receiving a reply.
They probably envisioned something like...
Phone: Where am I?
Tower: Shiii I dunno where you aaat?
Phone: Grrr, Google! I am connected to wifi access point "ATT" with SSID:12345678945 Where am I?
Google: Looks like syrusfrost was there last week, he was at 32.12345/33.12345 and he used GPS satellites.....
I really don't know how google is doing the Wifi geolocation, they may be parsing some of the wardriving databases out there for the major metro areas, hell when you drive with maps and wifi on you may be wardriving for google, wouldn't that be interesting...
Mikey1022 said:
i never used the built in gpa, so far.
I use my bluetooth keychain gps. had it from my old excalibur.
works great
Click to expand...
Click to collapse
Hows the battery life?

Assisted GPS - Don't use it!

My Touch Pro ran TomTom flawlessly until a couple of months ago when I got a problem with the GPS device (not the signal) being lost every few seconds. It would reappear again for about 5 secs then off again. Despite soft resets etc, I suspected it might be the SD card at first as I tried many restart combinations with the card in/out etc and as it seemed to help on one occasion I put it down to that. But it did happen on a regular basis.
I now have the X1 with its superb GPS implementation, I was very impressed for a few days... until you guessed it, this problem started happening again!
Luckily I remembered the only setting I had done prior to this occuring was to use the Advanced Config application, where I enabled the AGPS feature. So... I went back in and disabled it and the problem disappeared immediately. I used Advanced Config on the Touch too, so that must have been the problem for sure.
I notice that AGPS is disabled by default. Why HTC did this must mean there is a problem with this feature.
So be advised, not to use the AGPS unless anyone knows good reason to and has a fix for the problem I mentioned.
I ran into the same problem. Turned on agps in advance config, used tomtom 7 and keep getting drop signal. It would pick up the sat signal for a few second and lose it, what interesting though when I use google map it would track me fine, no lost of signal. I can see my "dot" on google map moving along. When I drive, haven't tried it with other nav software to see if this was an issue. I still wonder why they have agps turned off though as default.
i think even if its set to "disabled", its enabled. a-gps must be hard coded in the hardware itself!
ps: i have the same problems when its "enabled".
I think it's the AGPS file that might have corrupted. You can solve this by re-download AGPS file and everything will be fine.
It happened to me once or twice, but it's not a reocurring problem so I did not bother much.
which agps file?
Guess you talk about an A-GPS setting in Tom Tom?
I cannot follow your conversation. With Mobile Navigator, which has no switch to enable or disable A-GPS it works pretty fine.
Sat-fix within seconds - thanks to the provided A-GPS function of the X1, which I don't think can be disabled on teh X1, until you don't update the information frequently with the Quick-GPS application.
Maybe Tom Tom can't interpret the A-GPS information?
How long does a Sat-Fix in Tom Tom take, when you disable A-GPS (in Tom Tom)?
Eric
we are talking about a tool called "advanced config tool". there is an option of enabling and disabling a-gps. "disabled" works best for most users...
you can have a 3d fix in seconds also with no a-gps.
Eric X1 said:
I cannot follow your conversation. With Mobile Navigator, which has no switch to enable or disable A-GPS it works pretty fine.
Sat-fix within seconds - thanks to the provided A-GPS function of the X1, which I don't think can be disabled on teh X1, until you don't update the information frequently with the Quick-GPS application.
Maybe Tom Tom can't interpret the A-GPS information?
How long does a Sat-Fix in Tom Tom take, when you disable A-GPS (in Tom Tom)?
Eric
Click to expand...
Click to collapse
It's incredibly quick (even indoors) to fix a position without AGPS. I admit I haven't knowingly had any noticable problems outside of TomTom but this is something I use a lot. It copes admirably inside, in built-up or shaded areas. No real need for AGPS then! I did try updating my QuickGPS file by the way, to no avail. Disabling was the only fix!
The FIX IS TOO FAST!!!
But I don't have this problem.......
DocMAX said:
we are talking about a tool called "advanced config tool". there is an option of enabling and disabling a-gps. "disabled" works best for most users...
you can have a 3d fix in seconds also with no a-gps.
Click to expand...
Click to collapse
My X1i doesnt have an "adavanced configuration tool" application. Is this a 3rd party addon that you have installed, or is my device just configured differently?
DocMAX said:
which agps file?
Click to expand...
Click to collapse
xtra.bin in \Windows directory I believe
one way to verify if the problem is due to the AGPS corrupted file, is if you encounter the problem, delete the xtra.bin and see if the problem goes away.
kiwiandy said:
My X1i doesnt have an "adavanced configuration tool" application. Is this a 3rd party addon that you have installed, or is my device just configured differently?
Click to expand...
Click to collapse
you have to download it http://forum.xda-developers.com/showthread.php?t=317070
it's our swiss army knife, but be careful
I think people may be getting confused between a-gps and what quickgps does.
My take on this is:
QuickGps downloads a file which contains a list of satellites to speed up getting a signal. Works very well on the x1
this is governed by HKLM/Software/HTC/QuickGPS
A-gps gets an approximate location from your cell tower and feeds 6 virtual satellites signals through the com port set up in the control panel.
It constantly does this, using memory-map software you can see that the signal drops and comes back every second or so. it seems to overwrite what is actually coming from the gps chip as I've seen 4 high quality satellite signals disappear to be replaced with 6 from the a-gps nowhere near where I was.
There's a setting in the registry section concerning A-gps which has "GPSmode" which is set to 2 I wonder what the other values are and do, I havent played with those yet.
You can change the refresh interval I set mine to be 5 when on foot
HKLM/Software/HTC/SUPL_AGPS
I agree with pretty much what you have said (the difference between Quick GPS [sometimes also known as Assisted/A-GPS] and the conventional, location-based AGPS)
However, I don't believe, unless somebody scientifically, or empirically prove, that the phone will receive virtual satellite feed/signal once it acquire the proximity based on the LBS signal. Because to do that, you need to have a data carrier, and it's either via GPRS/UMTS data connectivity (not possible since I would have noticed the data transmission), or radio frequency that satellites transmit on. It can't be GSM/W-CDMA since they operate on the different frequency as GPS, or if it indeed transmit the "virtual satellite signal" on the GSM/W-CDMA network, then I'm sure you will notice it as part of your monthly telco billing?
You may argue that the server is transmitting the virtual satellite signal on the GPS radio frequency, if so, that'll be new development in the AGPS technology since HP iPAQ 6515 first come out employ. However, there are few consideration point;
1. GPS radio frequency does not operate well across barriers, which means the 'virtual satellite transmitter' must be transmitting at a higher ground otherwise it won't work
2. The GPS receiver must be able to reconcile signal from virtual satellite signal and 'real' satellite signal, which means added layer of processing at the phone end, which in my opinions offer more complexity than effective solution.
That said, I just read that the Quick GPS service provider supports 50bit navigation raw data streaming, so I might be wrong afterall.
fards said:
I think people may be getting confused between a-gps and what quickgps does.
My take on this is:
QuickGps downloads a file which contains a list of satellites to speed up getting a signal. Works very well on the x1
this is governed by HKLM/Software/HTC/QuickGPS
A-gps gets an approximate location from your cell tower and feeds 6 virtual satellites signals through the com port set up in the control panel.
It constantly does this, using memory-map software you can see that the signal drops and comes back every second or so. it seems to overwrite what is actually coming from the gps chip as I've seen 4 high quality satellite signals disappear to be replaced with 6 from the a-gps nowhere near where I was.
There's a setting in the registry section concerning A-gps which has "GPSmode" which is set to 2 I wonder what the other values are and do, I havent played with those yet.
You can change the refresh interval I set mine to be 5 when on foot
HKLM/Software/HTC/SUPL_AGPS
Click to expand...
Click to collapse
zenkinz said:
I agree with pretty much what you have said (the difference between Quick GPS [sometimes also known as Assisted/A-GPS] and the conventional, location-based AGPS)
However, I don't believe, unless somebody scientifically, or empirically prove, that the phone will receive virtual satellite feed/signal once it acquire the proximity based on the LBS signal. Because to do that, you need to have a data carrier, and it's either via GPRS/UMTS data connectivity (not possible since I would have noticed the data transmission)
Click to expand...
Click to collapse
when you enable a-gps in the registry it establishes a data connection, or at least it does on my phone.
In my house I get a variable signal, it can drop the data connection easily (and does)!
When I first tried A-gps enabled in the registry it tried to connect, couldnt and memory-map reported no signal. It then connected I got 6 satellites listed till the data connection dropped. This makes me think it's using a data connection.
I disabled all data connections using paul modacos "nodata" and didn't get any "satellites" picked up. My quickgps was upto date at the time and outside I would expect to get a decent "proper" satellite lock.
the SUPL-AGPS section of the registry also contains the following.
Server IP 10.1.101.63
Server Port 7275
Which suggests some form of data connection. Remember this has nothing to do with quickgps or the ephemeris data that gets.
Have a look at http://wmexperts.com/articles/gps_vs_agps_a_quick_tutorial.html
&
http://en.wikipedia.org/wiki/GPS_Phone
A typical A-GPS-enabled cell phone will use a data connection (internet, or other) to contact the assistance server.
Click to expand...
Click to collapse
-----------------------
edit Have just tried again to confirm what I wrote and not getting anything through a-gps at all! I wonder if there's something in this custom rom that's changed things.
But I am being told Ive got a HDop of 666.6m which is a bit spooky..
step outside and I got 9 satellites with 8m hdop back inside and I'm getting standard fix 5 sats 2m HDop flashing on and off every second (signal/no signal) but no data connection being used, so it looks like I'm wrong, so I'll take it all back!
Need to work out what's going on now..
I was having this same issue. At least its good that its not just my device. I tried deleting xtra.bin from both \windows and \temp and it did not help.
Just some clarification on QuickGPS and AGPS. For a regular stand alone GPS to connect, when it first finds a satellite it must download ephemeris data. The ephemeris data contains info about where all the GPS sats currently are in the sky. The ephemeris data is broadcasted by every satellite periodically. A regular GPS must wait for the beginning of the next transmission. If signal is lost mid transmission, the GPS reciever must wait for the next transmission and start all over again. Only once this data is downloaded can a lock begin to be calculated. What quickGPS does is download the ephemeris data from the internet so that next time you request a gps lock, this sometimes lengthy process can be skipped. quickGPS downloads a file called packed ephemeris and places it I believe in the windows directory.
AGPS on the other hand simply supplements info from the sattellites with info from the cell network. What towers you are currently near gives an approximate location (the mechanism that google my location uses) which then tells you which satellites to look for. When fards said it feeds virtual satellite info, he doesn't mean it actually broadcasts fake satellites via RF. It just feeds extra info to the GPS driver. Also, there are lots of calculations to do to maintain a lock. Once the receiver is getting sattelite signals it can send this information over the internet to the AGPS server which is a much more powerful computer that can do these calculations much faster. The server calculates the lock for you then sends you your position information back over the internet. This is why apgs enables a data connection.

blackstone is a real GPS ?

may be a dumb question.
Is blackstone has a GPS (not AGPS) ?
ie. without a sim phone card , it can still receive GPS signal for mapking ?
It's a real GPS, works great with, for example TomTom.
yes gps works without a sim card. agps is also available through registry settings but requires a Data connection.
lots of people seem to think that aGPS is a cheap substitute for normal gps
but thats not the case aGPS is normal gps plus the ability to get locations
from cellphone towers if one can't get a clear gps signal like if one enters
a long tunnel
http://en.wikipedia.org/wiki/GPS_Phone
aGPS is often mistaken as location-based service (LBS) or server-based GPS. mainly because the first generation of "Quick GPS" is also known as AGPS, which essentially is to download the satellite orbit path in advance instead of get it directly from the satellites at the point the receiver is trying to get a fix. The download process (receiving it from satellite) can be a lengthy process (30sec or longer depending on the reception level) thus the purpose of QGPS/AGPS.
I wrote a short article on the myth about AGPS, you can take a read if you are interested
Does anyone know what GPS chip is actually in the Touch HD? Is it a Sirf III? Is Static Navigation "ON" by default?
gregwee said:
Is it a Sirf III?
Click to expand...
Click to collapse
No, it isn't. GPS is integrated in the MSM chip, I think its called something like Qualcomm MSM7201A gpsOne.
zenkinz said:
aGPS is often mistaken as location-based service (LBS) or server-based GPS. mainly because the first generation of "Quick GPS" is also known as AGPS, which essentially is to download the satellite orbit path in advance instead of get it directly from the satellites at the point the receiver is trying to get a fix. The download process (receiving it from satellite) can be a lengthy process (30sec or longer depending on the reception level) thus the purpose of QGPS/AGPS.
I wrote a short article on the myth about AGPS, you can take a read if you are interested
Click to expand...
Click to collapse
thanks very much ..
thanks all for explaining ...

GPS.....A-GPS SCAM?? The gps drama sequel....

****************************************************************
"EDIT" UPDATE (7 oct. 2010)
Well you dont need to go actually much further then this first post!
Things got out of context over here, furthermore I decided to give
my external gps receiver a break and run some more tests with
the internal one of my SGS.
And the results I got were much better than any
other phone I tested before. Except the ones with a build-in SirfstarIII chipset.
If you have Gps issues,Just move on to this thread:
2nd edit (20 Oct, 2010): That thread was removed without any warning or explanation so I posted the videos in another thread:
http://forum.xda-developers.com/showthread.php?p=8903056#post8903056
END EDIT
RCinFLA said:
Like to share my experience as cellphone chipset designer and my dealing with various parties involved with GPS in phones.
Many of the issues are caused by business interests involved and there are quite a few parties plying to control location based services revenue stream.
SUPL, secure user plane protocol AGPS was created by network operators interest in mine, with the objective of putting them in the controlling position when it comes to extracting revenue from location based applications on their network.
Control plane AGPS is a general system where network operator independent entities can create a assist server along with possible services offering. They can encrypt their access to allow only subcribed (paying) users to access their service. The network operators has little control over this scheme.
With SUPL, in most cases, network operators outsource the location server function. Network operator hold location of their cell tower, as a total database, in close confidence. The network tower locations are also very dynamic over time. I believe the AGPS contractors don't get reliable and timely updates from the network operators.
Then there are third party business like 'Skyhook' which is trying to work around the network operator roadblocks by establishing a 'ponzi scheme' server database. If your phone has a good GPS location lock and detects a WiFi network, Skyhook's background app will have your phone send a message to their server reporting the SSID of the WiFi and its location. They then sell their server AGPS service to other companies, like Motorola, for inclusion in their phone software. Motorola may run into conflict with network operators. A network operator might refuse to buy a Motorola phone model with Skyhook installed on it. I noticed from the Captivate forum that the ATT version of Galaxy S has Skyhook capability.
Google is the 900 pound gorilla and is trying to wrestle control of location based services from network operators.
Finally there are the GPS chip manufacturers. Almost all of them have an AGPS server scheme of their own and try to promote it. The frontend processing (up to recovery of raw 50 bps satellite data) has unique hardware and firmware that are considered proprietary by the GPS chip manufacturer. In most cases a phone manufacturers like Samsung or Motorola are not allowed to have the software source code for this firmware or information on the actual interface protocol to the GPS chip. They are given a bundled binary file that the phone manufacturer software just dumps to the GPS chip at startup.
It is now up to the phone manufacturer to implement the GPS chip and antenna systems (along with WiFI, Bluetooth, Near Field Comm, and multi-band cellular) and provide software interfaces and drivers necessary to run the GPS function.
For size and cost reasons most recent GPS chips rely on the main application processor within the phone to actually do the GPS fix calculations. The software for this is provided by the GPS chip supplier but it must be coordinated with the particular applications processor chip used by the phone. It must share processing time slicing with the apps processor and work with operating system software resources such as RAM and ROM management running on the phone.
This is the first obsticle as most of the GPS chip suppliers have little expertise in the OS's that may be used (like Android or Symbian). The phone manufacturer usually has to provide help to create and debug the GPS driver software but the drivers are responsible/owned by the GPS chip supplier. There can be unique hardware/software interfaces that must be dealt with, like providing GPS TCXO calibration and cellular corrected frequency timebase to the GPS chip.
Then there is the OS's GPS interface. There can be translation software layers involved here. One such interface is based on GPS NMEA protocol but with additional hooks for things unique to phone operation like battery saver power strobing, and the complicated Secure User Plane or Control plane interface.
The AGPS system design landscape is litered with intellectual properties (patents) by many parties. Qualcomm is a dominate player here since their aquistion of SnapTrak company years ago. Royalties are paid to Qualcomm for every WCDMA phone sold, not only in AGPS area, but on basic CDMA patents used in a UMTS (Wideband CDMA) phones.
Now as to Samsung Galaxy S implementation of Broadcom GPS.
I think there is a lot of evidence that Samsung had early issues with the GPS antenna contact hardware. This has probably been corrected on recently manufactured phones.
I think the firmware supplied by Broadcom has the bandwidth of the correlators tighted down to provide greater sensitivity. This is great as long as there is a very good AGPS system to provide initial satellite ephemeris data. Without a good AGPS network providing satellite information the initial search and lock can take a very long time with narrow bandwidth frequency bins.
I have not seen evidence with my experience that my two Vibrants are receiving any reliable AGPS information from the T-Mobile network. They do seem to get rough Almanac satellite info from Google or other third party apps. These may be based on WiFi detection more then T-Mobile cell tower locations.
In LBStest I noticed that GPS Operational Mode has been set to 'Standalone'. I interpret this to mean AGPS is deactived. I don't see any difference when I switch to MS based assist, and clear the GPS saved memory to prevent it from prejudicing time to first fix lock test. Switching SUPL server to supl.google.com and port 7276 (with MS based operational setting) just seems to make my phone lockup for short periods of time.
Once phone does get full lock on satellites its performance is quite good. (my two Vibrant's were purchased in early Feb 2011). It rivals my Garmin SiRFstar III based GPS unit in locked on sensitivity while inside a building.
I think the AGPS system issues will get worked out over time.
The Qualcomm based CDMA2000 systems (like Verizon) will likely have better initial coordination on AGPS system operation. CDMA2000 also provides network timebase directly compatible with GPS.
Click to expand...
Click to collapse
*******************************************************************
All this nagging about GPS.....that it is not working in many devices and it's working in other many.....and of course I am talking about those ones who still would go for ONLINE gps navigation.....
In my humble opinion, what you guys should be asking yourselfs and the big corporations is, why nowadays, 99% of the smartphones(so not just sgs), even the most expensive ones are build with weak, less capable internal gps receivers, forcing users to go online(celular network /a-gps) or using external bluetooth gps receivers to get stable satellite fixes that means stable navigation.
Years ago, many of the first smartphones came with sirfstar chipsets or alike , so once again, why not now? That's the question that should not be ignored or forgotten.
A friend of mine, that would not dare to pay more than a 100 box for a phone, bought an ancient ETEN device on a sale for 40 box with that old windows mobile 5 and guess what...the internal gps get fast fixes just like any standalone gps device because it got the same sirfstarIII chipset
Why the heck, the expensive so called high-end smartphones of today are not build with better gps chipsets? Why A-gps? So we are forced to get data accounts?
And what happens when I want to navigate abroad? Roaming?
For data transfer and internet I use wifi; I have it at home and I find hotspots everywhere...I will save those extra 120 euros(or more) per year (data account costs)
And nobody will force me to get one(internet/data account); not even for gps navigation that I so much use..
I use gps navigation only offline, using a external bluetooth device on a daily basis and, many times abroad; it works like a charm on my SGS; and I am talking about serious GPS car navigation software like iGo, Sygic, Navigon etc. .
Don't even use Google maps or alike.
I cannot tell you how my sgs is doing on online navigation, I dont have a data account so I wont even try it.
But once Samsung get this online gps navigation thing fixed, you guys should concentrate your energy on the real issue:
The A-gps scam
And for all the corporations out there: Just deliver a device with a capable gps chipset and you will sell millions..
And for all the users out there: Just get a good compact external bluetooth gps receiver and stop nagging....
Thanks to 3rd party developers, the Android OS on my SGS can be "fooled" and I can connect any navigation software to my bluetooth gps receiver threw programs like Bluetooth Gps Mouse Unlimited and Gps Provider.
I do have to " allow mock locations" at settings first...
« »
¿Ein? You don need data to get GPS fix, A-GPS is only an aid to get faster fixes
I thtink you're a littel misinformed
LOL.. o boy.. the AGPS is to help say if your indoors so you can get a faster lock... the phone will work without it.
Ummm I can see why you would think what you think, but I do believe you are wrong.
Firstly: as far as I'm aware, the SGS has the same GPS chip as the latest TomTom standalone unit.
Secondly: I guess AGPS is a data feature, it uses the triangulation of cell towers and pulls information to assist a sat lock, but it is not really a different way of using GPS. Ultimately you still need to get a sat lock to use a GPS App.
So it may speed up this lock, but it won't replace it. It just means it'll take you a little longer to get a sat lock than without it.
So you have the choice use it or don;t use it, no-one is forcing you to use data.
Logicalstep
Oletros said:
¿Ein? You don need data to get GPS fix, A-GPS is only an aid to get faster fixes
I thtink you're a littel misinformed
Click to expand...
Click to collapse
Lol those online translators dont work that smoothly...
I don't need a data/internet account to use celular networks aid, that means a-gps.That mean going online via 3g or 2g...
But IF I don.t have a data/internet account added to my phone subscription, my phone costs will be much higher depending on my use....
You are missing the point anyway...
betoNL said:
Lol those online translators dont work that smoothly...
I don't need a data/internet account to use celular networks aid, that means a-gps.That mean going online via 3g or 2g...
But IF I don.t have a data/internet account added to my phone subscription, my phone costs will be much higher depending on my use....
You are missing the point anyway...
Click to expand...
Click to collapse
No, you're missing the point, you don't need any kind of data connection to use GPS, you can use it offline
Exactly...already the first line of Wikipedia says it: "Assisted GPS, generally abbreviated as A-GPS, is a system which can improve the startup performance of a GPS satellite-based positioning system."
There is, however, a related issue w/r/t A-GPS and a data account. Back on WinMo, I could download the ephemeris data to speed up the GPS fix for one week in advance (I think it was called QuickGPS or something on my HTC TouchHD, also had sth. like it on an old Eten). This allowed you to get a quick fix for said week, even without a data connection. Android, on the other hand, seems to download this data on the fly - meaning that if you don't have a data account you will experience a slow fix until your almanac has been filled "naturally" by the satellites you're seeing. I experienced that while on vacation this year without a roaming data contract - it took me a good 3-5 minutes to get the first fix and it was good from there on (well, as good as the SGS GPS gets ). I'd love to have some tool that does exactly what QuickGPS did, but I am not aware of anything like it.
TriC_101 said:
LOL.. o boy.. the AGPS is to help say if your indoors so you can get a faster lock... the phone will work without it.
Click to expand...
Click to collapse
I have always smile in my face when someone thinks he can get a lock indoors..
Yes in a cartoon box you can. Not in real building I'm afraid.
And for all those who think SGS's GPS is usable without A.
Try it.
You will see.
Dont post things you just caught on wikipedia.
xan said:
I have always smile in my face when someone thinks he can get a lock indoors..
Yes in a cartoon box you can. Not in real building I'm afraid.
And for all those who think SGS's GPS is usable without A.
Try it.
You will see.
Dont post things you just caught on wikipedia.
Click to expand...
Click to collapse
I can get a lock on 6-7 Sat no problem inside.... and so can lots of others.. don't know what your doing wrong but its not hard to get a lock inside.
Pics or it didnt happen
seems you all are little misinformed as to how the gps on android specifically sgs works. It is actually three systems at work here. Gps standalone without gprs and cell triangulation which gets lock within a minute same as standalone bluetooth units (they also take up to a minute from cold boot but because generally it is plugged in the car lighter and always on people think its blazing fast).then you have agps that downloads preloads data regarding satellite location in regards to your position via network instead of downloading same data directly from satellite thereby saving time. Both these can be used without checking network location in settings so to recap if your network location is unchecked you are still using agps as long as you have network connection (data connection that is).and samsungs system for agps being better than others cause it downloads data for while week as opposed to others downloading data everyone gps is turned on. Third level is network triangulation via cell towers that gets you that instant lock at the cost of accuracy useful mainly to let apps get your general location without having to engage real gps thereby saving power as well as give maps a chance to start calculating route while gps is still getting lock therefore appearing to operate faster.
Idan73 said:
Gps standalone without gprs and cell triangulation which gets lock within a minute same as standalone bluetooth units (they also take up to a minute from cold boot but because generally it is plugged in the car lighter and always on people think its blazing fast)
Click to expand...
Click to collapse
Standalone gps's got their batterys, and thus they start "warm".
Thing is, standalone SRIF3/4 gps gets a warm lock without any AGPS nor network triangulation within 5-10 seconds. SGS (and bunch of top-of-the pack devices) cant come even close to that.
the GPS on the SGS works fine offline
i don't even have data on when going on long road trips
you just need an offline GPS software with maps, like CoPilot or some other one you like
xan said:
Standalone gps's got their batterys, and thus they start "warm".
Thing is, standalone SRIF3/4 gps gets a warm lock without any AGPS nor network triangulation within 5-10 seconds. SGS (and bunch of top-of-the pack devices) cant come even close to that.
Click to expand...
Click to collapse
Sure they do. Sgs warm lock is 5 to 10 seconds as well. To test get the lock first then turn of data and network lock then start gps.restart of the phone same as restart of the standalone counts as a cold boot and takes about minute.
xan said:
Pics or it didnt happen
Click to expand...
Click to collapse
Here ya go.... I don't have to prove anything just look on youtube.. This is the phone on for just 10sec.. if I had waited it would get down to about 10 feet... this pic was taken in a room where I get the lowest signal. and I live in a Condo with 2 foot concrete walls.. I don't have a digital camera.. this was taken with my old Samsung dumb phone.. but it does prove you can get a lock inside no problem.. also if i'm in a house I can get 6-7 sats to lock in the condo 5 at the most in that room.
only 3 sats and maybe the walls are thin
Polarfuchs said:
only 3 sats and maybe the walls are thin
Click to expand...
Click to collapse
LOL Trust me the walls and not thin.. i'm on the 10th floor of a 25 floor Condo complex. I get alot more signal is a house.. Now my X10 can get about 7 Sats locked in the same room. and down to 5 feet. but the point was you can get a lock inside..
I'll try it.
I live in a 3 stories house at ground floor. The shutters are down and I'm 1 meter away from the windows.
After 3 Minutes I get 5 sats in view but none used.
I'll hang on.
Even after 10 Minutes I only have 5 satellites in View and zero in Use.
So no fix for me.
The numbers on top of the bars are from 15 to 25.
Logicalstep said:
Ummm I can see why you would think what you think, but I do believe you are wrong.
Firstly: as far as I'm aware, the SGS has the same GPS chip as the latest TomTom standalone unit.
Click to expand...
Click to collapse
Most of Tomtom devices got a SiRFstarIII™ GPS chipset
If the GS got such one the amount of GPS threads in this Forum would be reduced considerably
What is your awareness based on?
Oletros said:
No, you're missing the point, you don't need any kind of data connection to use GPS, you can use it offline
Click to expand...
Click to collapse
Idan73 said:
seems you all are little misinformed as to how the gps on android specifically sgs works. It is actually three systems at work here. Gps standalone without gprs and cell triangulation which gets lock within a minute same as standalone bluetooth units (they also take up to a minute from cold boot but because generally it is plugged in the car lighter and always on people think its blazing fast).then you have agps that downloads preloads data regarding satellite location in regards to your position via network instead of downloading same data directly from satellite thereby saving time. Both these can be used without checking network location in settings so to recap if your network location is unchecked you are still using agps as long as you have network connection (data connection that is).and samsungs system for agps being better than others cause it downloads data for while week as opposed to others downloading data everyone gps is turned on. Third level is network triangulation via cell towers that gets you that instant lock at the cost of accuracy useful mainly to let apps get your general location without having to engage real gps thereby saving power as well as give maps a chance to start calculating route while gps is still getting lock therefore appearing to operate faster.
Click to expand...
Click to collapse
LOL... Lets put things in perspective :
1) Wich car navigation software do you use
2) when you UNcheck wireless networks =a-gps(in location and security) and you CHECk "use GPS satellites = build-in gps receiver and then you go outside, you start your car navigation software in you gs( taking into consideration that you have the righ map installed) how long does it take to get a fix so you can start driving?
3) Do you know the difference between a cold and warm start? Why the heck some of you mention car lighters????
Please just answer me these 3 questions and meanwhile I will post some educative information

[Q] integrated GPS on both Rogers and AT&T Focus

Does both Rogers and AT&T Samsung Focus have a built in GPS (don't need a data plan)? Ever site I've looked at for the specs gives conflicting information.
fastmhc said:
Does both Rogers and AT&T Samsung Focus have a built in GPS (don't need a data plan)? Ever site I've looked at for the specs gives conflicting information.
Click to expand...
Click to collapse
As I understand, my focus at&t has built in GPS that can be used with and without a data plan. It just depends what GPS software you are using for instance any GPS software that uses realtime updates or online maps requires data to be used while GPS is enabled...some 3rd party software use stored on device offline maps that would not require a data plan. As for specific programs that use online and offline maps I don't know. I use a data plan so I don't have to worry about that stuff.
This is my understanding so if anyone has better insight be my guest
All WP7 phones have a GPS, just like they all have a camera, three front buttons, a gravity sensor, proximity sensor, ambient light sensor and a compass. There are free GPS apps that are on the Marketplace that will allow you to see the GPS does work.
In time, there will be standalone gps navigation apps for sale on the Marketplace, it just takes a little patience.
I just don't want assisted GPS (A-GPS). I want an integrated GPS chip. All phones dont' have a built in GPS (I think older iphones). I currently have a Samsung i8910 and it has an integrated GPS. I bought Garmin software to use the GPS maps and when I am overseas I just need to buy the maps for that region to access the maps. If you have A-GPS you have to buy a data plan from that country's carrier and using their network, you access the internet (google maps) to get your maps. I hope that is clear??
You totally misunderstood what A-GPS is.
Sent from my SAMSUNG-SGH-I897 using XDA App
Maybe I don't? this is a quote for the wiki page for GPS navigation for phones
" Some phones with GPS capability work by assisted GPS (A-GPS) only, and do not function when out of range of their carrier's cell towers. "
WP7's have A-GPS. They use both radio towers and satellites to obtain a fix on your location.
So yes, once a proper mapping application is released, you can travel to other countries without needing a data plan.
From wiki, sums it up pretty well i would say:
""Standalone" or "Autonomous" GPS operation use radio signals from satellites alone. A-GPS additionally uses network resources to locate and utilize the satellites faster as well as better in poor signal conditions."
Source:
http://en.wikipedia.org/wiki/Assisted_GPS
fastmhc said:
Maybe I don't? this is a quote for the wiki page for GPS navigation for phones
" Some phones with GPS capability work by assisted GPS (A-GPS) only, and do not function when out of range of their carrier's cell towers. "
Click to expand...
Click to collapse
Most of today's cell phone GPS chips can work either in standalone mode or Assited mode. A(ssited)-GPS helps to speed up your initial satellite lock by downloading satellite information from network. If you have no data connection, the chip will fall back to standalone mode. With A-GPS properly working, you can achive first lock within 10 seconds. Without it, you may have to wait for couple minutes for your first lock. After the initial lock these GPS chips work autonomously unless you use MS-Assited A-GPS mode. With the power of today's Smartphone, there is zero reason for using MS-Assisted mode unless you're using it in E911 situations.
It is ultimately the navigation software you choose determines whether or not you need cell data connection. Currently standalone navigation software on WP7 is quite limited or non-existent. If that is important to you, you may want to look for other Smartphones like iPhone or Android phones. Your old WM software won't work in WP7.

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