GPS settings / connection problems - XPERIA X10 General

Hi,
Could anyone please explain the various settings for GPS in the "settings" menu (under "location")? I find that the manual and tooltips are not very informative.
Particularly, I don't understand the difference between the first choice ("wireless networks"?) and the third choice ("assisted GPS"). I understand that the phone may use wifi or mobile network to detect my position (instead of or in addition to GPS satelites), but I don't know which of the two options to choose for this.
Also: When I enable "wireless networks", what does the warning that pops up mean? It mentions that data will be collected even when no software (GPS/map) is running. What is that? And what is the difference between enabling this and the fourth option ("share with google")?
Finally:
Does your GPS immediately start working when you enable it? Myself, I need to enable/disable GPS using the desktop widget and the various GPS settings several times before it managess to find my location. (My position is not the problem - once detected/connected, it works fine.) I still don't understand which combination of settings it is that finally makes the GPS work as expected.

As I understand the first option "Wireless Neworks" will rely entirely on data from Cell Towers e.t.c to determine your position. I guess this will be less accurate.
"Assisted GPS" enables your device to get a faster lock on your location by collecting available data from cell towers first before using the GPS receiver.
I think if you were only to activate the GPS in some circumstances it would take a lot longer to get a fix.
"Share with Google" just allows the gears addon within the browser to share your position with google allowing them to return results based on your location.
That's my take on those options.

"Wireless Neworks" - is using cell towers and wifi to locate you.
Probably they have (or use a 3rd party DB) for that. Anyway, is not (very) accurate.
"Assisted GPS" - i'm not 100% sure but i think is connecting to a location server to get the location of the GPS satellite so, will lock faster (at least this is what my Nokia 5800xm is doing).
The warning message you get is because google will (most likely) use your location (cell towers and wifi spots) to create and update their own database so, phones without GPS will still be able to use google maps.
Well, they probably do something more with that data but who knows what

I just wanna add that using any type of assistance for the gps chip in this phone is (in my personal oppinion) unnecessary. I am sitting inside my house, in my bed(with a window behind me) an in 10sec i get fixed on 10 satellites. Not much that can beat that ;-)
in addition, i am in the bottom floor in a 2floor house so it is alot of roof and cealing between me and the sky.
Sent from my X10i using the XDA mobile application powered by Tapatalk

Thanks for your replies. Much appreciated.
Just curious - which app do you use to monitor GPS satelites?
Also, does everyone's GPS find your location rather quickly after enabling GPS? I usually get the message "Your current position is temporarily unavailable", I retry, same result, I retry, same result ... Only after I disable/enable GPS several times, my position can be found.

My GPS usually finds my position rather quickly first time I switch on GPS. I have aGPS (Assisted GPS) enabled too, this way your phone gets help on locating the sattelites position from your mobile provider, hence locking onto GPS signal faster (is to my understanding).
Plus, if you're standing in an area with tall buildings, your position will be less accuratelly pin-pointed, bouncing GPS signal and all.

I'm using GPS test by chartcross ltd. Avalible in the free android market, and i really like it!
Sent from my X10i using the XDA mobile application powered by Tapatalk

I never turned on A-GPS on this phone. There is no need for A-GPS.
This phone have fastest GPS fix of all phones.

I have noticed when I am running on 3G (H) I get the "location temporarily unavailable" notice, but if I force it to not go to 3G it will be E and I get my location. This holds true if I have setting for using GPS or not.
This seems to be a problem with Google Maps using the data transfer method of 3G (H) versus E.

Related

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.

Optimal GPS settings for faster GPS lock on HD2? (Also using GarminXT)

Hi all,
I didnt want to start a new thread, but after searching the forums and google for a long time, i decided to bring it up
So ive had my HD2 for about 2 days now, and I recently installed GarminXT (I used to have it on my Nokia N82)
the problem i'm finding is that the GPS doesnt lock as fast as i thought it would be..
GarminXT has not been locking on (little over 5 minutes now)
I'm a noob to Windows Mobile and HTC so please bear with me!
1. How do i know A-GPS is working? Is it automatically enabled? (This wasnt the case for Nokia as you could manually turn off A-GPS and use strictly GPS signal). Under Location settings i have "Location Service Settings" = ON
and HTC Location Service = ON
2. Im still not 100% sure what QuickGPS does. I've read about it , but all i concluded was that it uses your data to get a faster GPS lock.
So i tried running QuickGPS and it updates no problem.
I open GarminXT and it doesnt lock on. Do i need to use this?
3. Can someone tell me if these are the optimal GPS settings? I kept searching around the forum but cant find one specific to the HD2.
So under "All Settings" > System > External GPS
Programs Tab > GPS Program Port = COM4
Hardware Tab > GPS Hardware Port = None > Baud rate = 4800
Access Tab > Managa GPS Auto = Checked
Are these settings correct? Or are there "tweaks" to it that I can change?
4. One last question:
Under GarminXT, i have the ability to choose 3 GPS options:
"Use Bluetooth GPS"
"Use GPS Intermediate Driver" = Checked
"Use Serial GPS" > Once selected, i get 4 other options to choose:
COM1: Bluetooth Serial Port
COM2: Bluetooth Serial Port
COM4: COM4:
COM9: 7500 COM port
Does anyone know if i should be checked on "Use GPS Intermediate Driver" or if i should be checking off "Serial GPS" > COM 4?
This is my first WinMo device with a data plan (I'm on EDGE speeds cause I'm in Canada), but I always had the impression AGPS would really help the lock times.
Anyone with help would be GREATLY appreciated!
Again, loving the new HD2
Thanks
For GarminXT, use intermediate driver.
For Google maps, use Com4, 4800 rate, that enables use of the compass.
Quick GPS should increase startup, and so far I had all fixes on HD2 under 30 seconds, and I did not change anything.
Normally GPS would download information about orbits of satellites from the satellites. That can take time, as it is one way communication and GPS can't ask satellite to send data again in case of error, it must wait untill the satellite starts sending them again by itself.
It is much faster to get that data via network .. and that is exactly what QuickGPS is for. Problem is that at least on my previous X1 there were many problems with it. The data from network was sometimes completely wrong, and you had to delete the file manually. That information is in temp\xtra.bin. Try to delete it and try again. QuickGPS does not test existence of the file, it will download new one in predefined time.
I'm still a bit confused about aGPS. I'm not sure what it is. Some people state it is the same thing as QuickGPS. Some say it is something to get quick basic fix based on BTS. But I haven't seen that in any application, except Google maps, and they seem to use their own technology and data for that.
But AFAIK, those 'location services' is generally Google's 'my location' exposed for other HTC applications.
I set it on max rate, do i do a mistake? I think that this is setting the speed or Im wrong?! Im connecting with sattelites below 15sec, with no other tweaks or quickgps...
^^
what's "max rate"?
btw, thanks for the replies
i'll look into deleting the cache file for QuickGPS and see if it does anything
Quick GPS allows you to download a weeks worth of GPS satellite position data (almanac data) at one time, helpful if for example you don't have a data plan - you can get your A-GPS data in one hit over WiFi. It helps speed lock time.
Not sure what is happening with yours, mine always locks in Garmin within 7-15 seconds, I have Quick GPS set to autoupdate, but otherwise no special tweaks or modifications where GPS is concerned.
Same here - in fact, the HD2's locking faster to GPS than my Touch HD ever did. I'm getting locks in the garage now whereas before I had none with my Touch HD. Haven't touched the default WM GPS settings or the Garmin one at all since I upgraded to the HD2.
GPs lover-Google map hater
Hi guys, firstly thanks for this thread as i too look for answer...and find some only here
i had the Diamond and now the HD2 and share the love.
Garmin maps are much more accurate and have even the smallest unpaved roads which Google map lacks. Google is so basic maps, i simply hate it...sorry Google...not to mention that it cost money to be online all the time
HD2 GPS confuse me. Sorry if I ask u basic staff but could not figure it up myself:
1. using the GPS w/google map, how u set simple setting, as: "north up" or ""track up" Route setting such as "faster time" or any other basic settings that I always had on my Garmin GPS including Garmin mobile XT?
2. What happend to voice navigation wiith google?
3. Reading your info, does it means that I can install Garmin mobile XT I got with Diamond on HD2 ?
4. Anybody know TomTom for HD2 (which I will get shotly from HTC?
I trust someone out here is smarter than me and will come to rescue
hey guys,
my HD2 is fine now, usually i just do a QuickGPS connect before opening Garmin XT and now it connects SUPER fast...usually under 10 seconds
Thanks for all the help!!
Google is not, and does not set out to be a full satellite navigation prpgram, so it doesn't have stuff such as 'North Up', 'Track Up' etc, nor does it have spoken directions.
For these you need a dedicated SatNav program like Garmin, TomTom, CoPilot or iGO8 which are all 'paid-for' applications.
TomTom will run fine but TomTom don't officially support it, meaning you can't download the correct vesion direct from their website. There are easy ways around this though!
With regard to some of the earlier posts- the HD2 can aquire a fix faster than any other device I've used (and I've used a lot!). I find QuickGPS makes very little difference, but as it uses only a small amaount of data I keep it updated.
QuickGPS and A-GPS are not the same thing, though there are quite a few different definitions of A-GPS. Genuine A-GPS is not used in UK, nor as far as I know anywhere else in Europe except by dedicated programs and platforms set up with the infrastructure (such as Apple, who use it to enhance the poor performance of the iPhone's GPS chip). It is used in the Far East, and works by enhancing your accuracy of positioning by using the data channels to send your current cell ID plus any other availble stuff like WiFi hotspot info, which is correlated to a database of locations, and sent back as an approximate position to the phone. Google Maps uses something like this if a GPS signal is not available- the 'Locate Me' feature will show you in a radius of around 1km.
The Baud rate makes no ostensible difference to the lock times or accuracy, as the data stream from the satellites is far lower than even the lowest baud rate. The NMEA default is 4800, and most software is happy to connect at that rate.
The google maps GPS finds me within 80 metres.. that's not accurate right? cause it puts it on wrong street technically.. When I first got it it did 800 metres =/
WOW, that was fast, thank you NeilM.
I will get Tomtom for free from HTC as it is included with Thai purchaded HD2.
Meanwhile I will try to load Garmin XT that I got with My Diamond at the time, let's see if the activation works...
As for Goole, well, I get 60 meter accuracy at the best, that make ones totaly lost in a city and for sure miss a turn, what a pity.
Thanks again for ever so fast reply.
When Google Maps is started it is finding your position throught the carrier's network and that is why it is not acurate at all. There is an option however, named "Use the GPS" in goolge maps and it becomes as acurate as any other navigation software It just have to engage an GPS lock as the others so do not blame google on this one Hence, you are not using the GPS when you get the inacurate positioning For the maps however you still have to be online But if you pay for your Garmin, iGo maps it would be that expensive and you can use it wherever you are ...
You absolutly right. i did use the "use gps" and it's accurate. The thing is that as heavy GPS user the lack of detailed info on google maps, and the inability to set the maps at your convinient (such as "track up" for example) it's nearly a secure way to go crazy while nevigating, specially off road...try to tilt your head to understand your position in real time when you turning and turning. Thanks for the gps tip.
I agree. Curent version of Google Maps is not suitable for navigation while driving indeed! It can help you get orientated sometimes or if you are looking for something big iGo and Garmin are in a whole new league of navigation sofware for now. However, the new version of Google Maps should be at least as good as the others but it is only available for Android at the moment and I dont see it coming to WM any time soon so we will have to stick to iGo, Garmin, TomTom and the others. I'm not using Google Maps for navigation at all by the way so It wouldn't be so difficult for me )
ragelord said:
the new version of Google Maps should be at least as good as the others but it is only available for Android at the moment and I dont see it coming to WM
Click to expand...
Click to collapse
It's called google navigation, not google maps - and it seems to kill every GPS program available today (thank god).
hey guys,
on the same topic, but different nav software. i use iGO 8, can someone please tell me what the optimal setting are for port and baud rate? i did the auto-detect and the signal is a little on/off.
also... is there a way to get iGO 8 to use the HD2s compass? i like the stand-alone compass of the HD2, but i think it would be swell to be able to have iGO's compass function working aswell.
sorry if this has been discussed before, if there is another thread i should be reading... please direct me there.
thanks for all your help.
cheers.
conscept said:
The google maps GPS finds me within 80 metres.. that's not accurate right? cause it puts it on wrong street technically.. When I first got it it did 800 metres =/
Click to expand...
Click to collapse
Eh, if I'm not wrong, that's agps at work.
It'll find you with the nearest base station. then slowly try to triangulate you. Normally, you'll be in an area with only 1 base station, so there's not much triangulation going on.
When I'm in city, it's pretty accurate. I get my approx distance within a couple of seconds, wait another 10 - 20 secs to get gps fix.
A-Gps and other things
A-GPS is just one thing: Assisted GPS. It is a toggle-- when you toggle it on, in your phone's settings, you will get the locational assistance of the cell towers. That is the towers them selves, two or more towers and your phone triangulate to give an approximation of your location. GPS also uses triangulation (derived from simple trigonometry equations) to determine your location and is much more accurate. In fact it can be ever more accurate as your device locks onto more satellites. I have found that the best thing to do is to turn off A-GPS. I don't know what it is but Googlemaps seems to have a terrible time locking onto satellites on Windows Mobile. But I have found, especially on Android 1.6 and above you get very rapid locks so long as you wipe out the telenav program. I strongly suspect that Google is undermining Windows Mobile in favor of supporting their Android system. They have turn by turn for Android but not for Windows Mobile and it seems like they are also building it not to lock sats nearly as well. You can force it to get moving by pre opening the GPS or other methods just prior to running google maps.
I think everyone should write google and tell them to fully support Windows Mobile (Phone)... T-Mobile is just about set to come out with the HTC HD2 in about a week (March 24th) and I intend to get one. I am not happy that it doesn't have a physical keyboard cloned from the Touch Pro 2, but I expect to like most of the rest of it.
Turning Location on is another thing. You are henceforth allowing all applications to know and your location. this can be helpful but it can also be a potential privacy risk. Of course it's easy to turn off and on. You might want to read the fine print.
Actually, I have a more basic question. Is there a soft "switch" or software application to actually turn the GPS on? On my HD2 I have a few GPS apps and all of them report the GPS being on or "no GPS Device found". Even Goggle maps, if I siwtch to USE GPS mode, keeps endlessly waiting for a GPS signal and then nothing happens. What am I doing wrong?
Thanks much
Gps htc hd2
In my experience with windows mobiles and internal gps, manage gps automatically is best and no ports should be assigned at all unless using bluetooth gps receiver! Also, sounds crazy too many but no every location on this big earth is withing available to public gps devices gps satelite paths (satelites going around the earth!) Make sure your outside the house or flat before thinking your gps ain't picking up. My hd2 is fast, my old mda3 was too and worked better inside but thats down to i was living in a different location at the time and at an higher altitude i would say. 1 of many other reasons could be that the military could be using the sat at the time which would render it unavail to public (offline)!

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] Anyone Elses GPS Aweful?

I have never had my GPS locate me via google maps. My Phone has no issues. Anyone else have GPS issues? any tips? Hopefully a software update fixes it? I have a friend who has the same issue.
[Should have read "awful", not aweful]
Nothing wrong with my gps. Have you upgraded to the latest firmware? Downloaded the A-GPS data (you can get this by using an app called GPS status)? Switch OFF wifi after you do, then leave it to get a full signal lock (takes up to 15minutes or so with a clear view of the sky).
toddmp said:
I have never had my GPS locate me via google maps. My Phone has no issues. Anyone else have GPS issues? any tips? Hopefully a software update fixes it? I have a friend who has the same issue.
[Should have read "awful", not aweful]
Click to expand...
Click to collapse
Make sure you are outside with a clear view of sky when you test. It can take any GPS up to 10 minutes to acquire the ephemeris information (satellite position at a certain time) and lock up. You phone cheats this by using the cellular network to provide a general location of where your are and therefore where to look for certain satellites.
thanks so much for the info guys. I had a feeling it had something to do with no cell phone band helping out. thanks!
GPS works fine here, as other have said the closer you are to the sky/window the better.
yeah..give your TF a few minutes to lock up sat positions (if you've never done this)..
this applies to most pure gps devices..cellphones can use cellular network signal to quickly locate your position but the data isn't really from gps itself.
http://forum.xda-developers.com/showthread.php?t=1088120
Hope this helps
Acid lestitious 2.0. Fugumod 2.4 800 mhz
jerrykur said:
Make sure you are outside with a clear view of sky when you test. It can take any GPS up to 10 minutes to acquire the ephemeris information (satellite position at a certain time) and lock up. You phone cheats this by using the cellular network to provide a general location of where your are and therefore where to look for certain satellites.
Click to expand...
Click to collapse
I wonder if it does the wifi cheat like maps for android phones, where it uses the known APs to determine location? I say that because when I first fired up my transformer yesterday, after connecting to wifi, I screwed around on maps and it found me inside my house in less than 30 seconds.
toddmp said:
I have never had my GPS locate me via google maps. My Phone has no issues. Anyone else have GPS issues? any tips? Hopefully a software update fixes it? I have a friend who has the same issue.
[Should have read "awful", not aweful]
Click to expand...
Click to collapse
its the reverse for me! in the same room of house i often cannot get a fix on my Optimus 2x. i use GPS Staus app. but i often get fix within 30secs. as a test i have both machines running the app next to each other and the transformer always gets regular fixes.
..... hmm just realised as i type this that i have a phone called optimus and tablet called transformer, and they both run android!!!
I get fixes with no wifi (ie: only GPS) within 30 seconds.
Quite the opposite, mine is extremely accurate. After it gets a fix on maps that little google person is standing right in my front yard in the satellite view! Better than my Droid!
Mine is almost instantaneous. Just tried it at home based on this thread and had a read in probably 5 seconds.
I have not been able to obtain a GPS lock until today when I set my location to use wireless networks. To me this is really stupid because the GPS shouldn't have to use any location settings to obtain a lock in my mind. That is if the GPS chip in the TF is a true GPS chip it should not to rely on a wifi signal to obtain a lock. If the GPS is turned on then it should lock.
I tested sygic gps navigation 11 and signal lock and quality was better than my galaxy s was pretty accurate
Sent from my Transformer TF101 using XDA Premium App
Works fine for me, apart from one minor detail. When I switch from Google Maps to another app, even for a few seconds, then the tablet has to get a lock all over again. There appears to be no way to set the GPS to keep a lock while Google Maps isn't the active program.
That, for me, makes Google Maps near-useless in a moving vehicle. Hopefully other third-party apps won't have this issue.
Google Maps is prety much useless on the Transformer for GPS navigation as a data connection is need. I have heard of people caching a route before hand but ..... Copilot Live 7 is out for android so that is one option. However if the GPS relies on a wifi signal in order to obtain a lock then it is about useless too.
toddmp said:
I have never had my GPS locate me via google maps. My Phone has no issues. Anyone else have GPS issues? any tips? Hopefully a software update fixes it? I have a friend who has the same issue.
[Should have read "awful", not aweful]
Click to expand...
Click to collapse
Gps works fine on mine....unlike my icons or Samsung...both returned
gps does use wifi to help gps locate, theres options to turn this off in settings, i went to pick up my dock today and couldn't get a gps lock while in the car with the transformer in my lap(gps status app showed 3 sats but none would lock) just lifting it up 12 inches closer to the windshield made 7 satellites pop up and instantly started getting locks
i think proximity to a window/line of sky is a big factor, and the transformer does have a true gps chip for those who seem to doubt it, also the navigation app keeps running in the background, its better to use that than google maps
No issues with gps here. The bastard finds me every time!
jadesse said:
However if the GPS relies on a wifi signal in order to obtain a lock then it is about useless too.
Click to expand...
Click to collapse
It doesn't rely on WiFi for a lock, it just uses it to allow a faster connection if you don't already have current ephemeris data downloaded. That's a limitation of all GPS receivers -- it takes a fair while to download the ephemeris data if you're out of date or have travelled a significant distance, and without it the device can't get a GPS fix.
You can think of the WiFi location system as analogous to a cellphone being able to use tower locations to help position itself while waiting for GPS ephemeris data.

GPS lock time problem

Hi,When I use my phone for finding my location without using data connectivity - without relying on A-GPS so my phone finds my location after a lot of time or sometimes google maps can't find my location.
How can I solve this?
Thanks.
After day or so it won't get fix at all. Samsung just did something wrong I'm afraid. Looks like the GPS in SG2 NEEDS data to work. I found the hard way on my trip to Japan. I know no solution.
So I cant change my gps settings?
Sent from my GT-I9100 using XDA App
GPS in the S2 is weird. Some days it locks in seconds other times it takes forever. I never use A-GPS.
Today I couldn't get it to lock but last night it was instant. So I restored a CWM backup from last night, rebooted and it locked instantly.
I played around with MIUI for a couple of days and found lock time much better than stock or custom rom.
Also, changing server with fasterfix makes no difference when its having problems locking.
I just don't get it.
Sent from my GT-I9100 using XDA Premium App
GPS Aids in Market. It will take a bit of time on first lock but from then it will be fast.
sxi200 said:
GPS in the S2 is weird. Some days it locks in seconds other times it takes forever. I never use A-GPS.
Today I couldn't get it to lock but last night it was instant. So I restored a CWM backup from last night, rebooted and it locked instantly.
I played around with MIUI for a couple of days and found lock time much better than stock or custom rom.
Also, changing server with fasterfix makes no difference when its having problems locking.
I just don't get it.
Sent from my GT-I9100 using XDA Premium App
Click to expand...
Click to collapse
How do you 'never use AGPS' ? Btw. my problem is not time of the lock. But the fact, that without network, I don't get fix AT ALL. With network AGPS reset helps (many apps can do that). But without network GPS works only for some time (AGPS data still valid). After that you just won't get fix. It even looks like wifi connection won't help, it has to be mobile network.
It's because of crappy gps reciever or it can be improved by another rom?
Thanks
Sent from my GT-I9100 using XDA App
It seems the problem is that GPS is in mode, where it simply relies on AGPS. In older ROMs there was app called LBSTestMode where you could change the mode to stand alone, or just AGPS based. This application is not in newer ROMs, so it cannot be switched. It clearly is just a software thing. Except it looks that there is no solution which does not involve flashing roms and/or rooting.
Dr.Sid said:
How do you 'never use AGPS' ? Btw. my problem is not time of the lock. But the fact, that without network, I don't get fix AT ALL. With network AGPS reset helps (many apps can do that). But without network GPS works only for some time (AGPS data still valid). After that you just won't get fix. It even looks like wifi connection won't help, it has to be mobile network.
Click to expand...
Click to collapse
Yeah I never use it. I don't tick 'use wireless networks' at all. To me that's fake GPS.
Since my last post, GPS has been perfect. Am able to lock up to 11 satellites sitting on the couch. On average it takes about 10 seconds to lock. Tested it at least 20 times today.
But who knows what will happen tomorrow!!!
Man, if you can only get a lock using wireless networks then I think your GPS might be stuffed.
Sent from my GT-I9100 using XDA Premium App
sxi200 said:
Yeah I never use it. I don't tick 'use wireless networks' at all. To me that's fake GPS.
Since my last post, GPS has been perfect. Am able to lock up to 11 satellites sitting on the couch. On average it takes about 10 seconds to lock. Tested it at least 20 times today.
But who knows what will happen tomorrow!!!
Man, if you can only get a lock using wireless networks then I think your GPS might be stuffed.
Sent from my GT-I9100 using XDA Premium App
Click to expand...
Click to collapse
That does not mean you don't use AGPS. AGPS is method, where data about GPS satellites are not downloaded from those satellites via GPS receiver, but rather from server via. mobile network. So I'm afraid you do use AGPS, unless you disable mobile networking (and wait about day for current data to become obsolete).
One thing I've noticed is that when I run Z-DeviceTest and bring up the GPS status display, it shows that none of the satellites have almanac data, and very rarely have ephemeris data. If that's accurate, that would suggest that if you've turned off AGPS and mobile networking, you could have some trouble.
3waygeek said:
One thing I've noticed is that when I run Z-DeviceTest and bring up the GPS status display, it shows that none of the satellites have almanac data, and very rarely have ephemeris data. If that's accurate, that would suggest that if you've turned off AGPS and mobile networking, you could have some trouble.
Click to expand...
Click to collapse
Nice find. First app I know which shows this. Now I can test if that almanac is downloading via GPS satellites or not.
Dr.Sid said:
That does not mean you don't use AGPS. AGPS is method, where data about GPS satellites are not downloaded from those satellites via GPS receiver, but rather from server via. mobile network. So I'm afraid you do use AGPS, unless you disable mobile networking (and wait about day for current data to become obsolete).
Click to expand...
Click to collapse
Ok. So does that would mean it's impossible to get a GPS lock without data enabled? Or just harder to?
Maybe I shouldn't have mentioned AGPS, but instead wireless networks which show your position even though GPS is not locked.
Sent from my GT-I9100 using XDA Premium App
sxi200 said:
Ok. So does that would mean it's impossible to get a GPS lock without data enabled? Or just harder to?
Maybe I shouldn't have mentioned AGPS, but instead wireless networks which show your position even though GPS is not locked.
Sent from my GT-I9100 using XDA Premium App
Click to expand...
Click to collapse
It seems it may vary with ROM, and it is possible to switch it, at least older ROMs contain service menu module (LbsTestMode) to switch it. But my SG2 seems to be unable to get a fix without network. It simply does not even try do download Almanac or Ephemerides data from the satellites.
Also for AGPS, mobile network must be used, not WiFi. As I understand it, those AGPS server names are virtual, and network provider redirects them based on location .. which is not possible via WiFi.
I wonder WHY there is such option at all. Do mobile network providers want us to be unable to get a fix without them ?
Dr.Sid said:
It seems it may vary with ROM, and it is possible to switch it, at least older ROMs contain service menu module (LbsTestMode) to switch it. But my SG2 seems to be unable to get a fix without network. It simply does not even try do download Almanac or Ephemerides data from the satellites.
Also for AGPS, mobile network must be used, not WiFi. As I understand it, those AGPS server names are virtual, and network provider redirects them based on location .. which is not possible via WiFi.
I wonder WHY there is such option at all. Do mobile network providers want us to be unable to get a fix without them ?
Click to expand...
Click to collapse
Hey Dr, I think you have diagnosed my problem
Every so often I turn off data and use only wifi. One day my GPS locks in seconds then the next it takes forever.
So I have now tested it a couple of times over the last couple of days, when I can't get a lock I turn off wifi and turn on data. All of a sudden GPS locks again. Interesting!!
Hopefully that is it. Will test again the next time it won't lock.
Sent from my GT-I9100 using XDA Premium App
Ha ! Breakthrough. I could get a fix without network ! But ..
I used newer version of 'GPS Status' app. It shows state of unconnected satellites with gray/blue/yellow based on how much data it has - none/almanac/ephemerides. So you can see if there is some progress or not.
So I disabled network (both wifi and mobile), disabled location from mobile network, left just GPS on .. run GPS status and used 'Reset AGPS'.
The connection has few 'phases':
1) you get signals from satellites .. you see it in power meter .. all are gray .. and their dots on the 'sky' view are all in the N. Sure, GPS does not know where the satellites are, and does not know where you are .. so it can't know where on the 'sky' they should show.
2) Some signals/dots turn blue. That means you have almanac data. Rough position of all satellites, which is transmitted by all satellites. That already means your GPS receiver was used to download some data from the satellites. Based on this, GPS can tell very roughly where you are, and will paint dots on the skyview.
3) Some signals/dots turn yellow. That means you successfully downloaded ephemerides data from that satellite, and it can be used in fix. Have enough of them, and you are done.
4) Some signals/dots turn green - you have fix. The error will get better over time as more satellites are used.
I took me over 5 minutes .. but thanks to this tool I could see I'm indeed receiving some data and there is some progress. Also it only worked outside, under open skies. I tried that in a car, in a bus, in a train .. after 10 minutes I did not get over phase 1. With AGPS I get fix in all such situations in few seconds.
It just looks like the data decoding module for almanac/ephemerides is not the same as for the time (which is used in fix itself). While time channel is quite sensitive and fine, data channel seems to have troubles with even slightest disturbances.
Still I'm happy I made it work in the end !
Btw. the fact that AGPS does not work over WiFi still holds.
ayosopov said:
Hi,When I use my phone for finding my location without using data connectivity - without relying on A-GPS so my phone finds my location after a lot of time or sometimes google maps can't find my location.
How can I solve this?
Thanks.
Click to expand...
Click to collapse
try fasterfix from market
I rarely have the data connection on (just to save battery) and WiFi is only on where I know I have a known connection - thus it is off when outside.
I put on the GPS then immediately run Sygic satnav program. I will have a fix normally within 30 seconds and a worst case of about a minute (that I can remember).
I have just tried switching off and on my phone, putting on the GPS (from the Pull down menu) and run Sygic. From switching on the GPS, I had a lock in about a minute.
KI3 Stock ROM
fred_up said:
I rarely have the data connection on (just to save battery) and WiFi is only on where I know I have a known connection - thus it is off when outside.
I put on the GPS then immediately run Sygic satnav program. I will have a fix normally within 30 seconds and a worst case of about a minute (that I can remember).
I have just tried switching off and on my phone, putting on the GPS (from the Pull down menu) and run Sygic. From switching on the GPS, I had a lock in about a minute.
KI3 Stock ROM
Click to expand...
Click to collapse
Could you try that with AGPS manually reset ? I recommend 'GPS Status' tool to do it, it's in 'tools' menu.
GPS lock time seems much improved in KJ4 firmware for me (i'm on orange 2.3.5)
all three DOP values in GPS Status now show figures (instead of infinity for two of them), and i'm getting reported accuracies of around 5 metres, instead of 14 - 20 metres on the older firmware.

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