yashsingh1/xdaforums huggingface dataset:
[Galaxy S I9000 General] Beowulf_pt:
Hmm disgusting results and quite disturbing as you're one of the few people here that I credit as reliable when it comes to informed *****ing about the lame GPS performance. Shame. I have been watching the SGS for weeks now and having the gut feeling that the poor GPS performance is due to a poor firmware/hardware implementation and perhaps it won't get fixed at all if it it all depends on hardware design decisions.

Shame, shame... still waiting for an actual fix but currently I suspect the SGS will never be a useful navigator. Perhaps the next generation of HTCs will provide a balanced product. I'm glad I haven't bought my SGS yet.

In any case, once again thanks for sharing all your interesting detective work on the chipset usage. :)
[Galaxy S I9000 General] sjdean:
Tried this again this morning and I had pretty good accuracy.

The following changes I think also increases signal strength. First time I've ever had 8 +30 SnR's in GPS Test. Come to think of it, for large times, 4 of those satellites were +40!

Ok, so firstly, MAKE A BACKUP OF JUPITER.XML under /system/etc

Then, make the following changes (Im not going to tell you how, if you need to know how, you're not ready for this change):

The reason I make this change, is because I note the section previously which advise:

So I took out BrcmRFwildBase, BrcmRFclkDiv, anBrcmRFclkRefHz

Certainly doesn't have a negative impact.

Additionally, change the normal job to this:

To be honest, Im not sure of the effectiveness of adding enable_low_power. It seemed better for me, but I may just have a good constellation of satellites. Put it like this, I started seeing 10 satellites after these changes with 8 satellite fix all +30. Some fluctuations from time to time, but first time I saw the bars all green.

Walking back today, I also saw 8 satellites, +30 SnR, 4 of those satellites +40.

But I cahnged it to enable_low_power="false" and it was the same.

Cya

Simon
[Galaxy S I9000 General] teryz:
Just to be sure, you do need to be root to do this, right?
[Galaxy S I9000 General] jdrake001:
GPS problem might be just a driver/firmware fix away

Okay, this may be old news, but felt quite reassured when I read from the teardown posts that SGS is using broadcom BCM4751 chip, which is (supposedly) an improved version over the gps chip found in iphone 4 (BCM4750)

unless broadcom effed up big time for this supposed upgrade, chances are high that it is capable, and we just need to wait for a better driver. Note BCM4751 was only announced in feb earlier this year.
[Galaxy S I9000 General] xfile087:
That's good to know! Every day I read more and more stuff like this and I'm glad I returned my iPhone 4 and got a Galaxy S instead :D
[Galaxy S I9000 General] sjdean:
Yup. You need root for that.
[Galaxy S I9000 General] larryccf:
sjdean - you might want to try something in your next testing - it might offer some insight into whether antenna issues are playing into this problem

i've known for some time that carbon is used in paints and plastics to color the object "black" - and carbon degrades radio signals (i built a couple of experimental category airplanes, both fiberglass, where the comm antennas were buried in the plane's vertical stabilizer (vertical tail fin) for aerodynamics). Normally on fiberglass airplanes, black paint is used as a first coat, before the primer, as black is a UV blocker, ie keeps UV rays from destroying the epoxy resin used to wet out the fiberglass. But on the vertical stablizers, we were advised to not cover the antenna areas with black, as it would block signal.

Also, i've worked with carbon fiber, and it will totally shield radio signals.- carbon fiber is basically created by vitrifying acrylic in high temp ovens so it's not like the carbon came from any iron ores.

to the point, someone on another forum posted what i understood to say, that testing his phone by removing his Tmobile black gel case, he got a better signal without. I had ordered a clear silicone one on suspicion that was the case.

But I wondered about the actual black plastic rear cover on our phones, so i

checked signal strength under the settings > status list, and with the cover on, signal was -111 dBm, with it removed it went to -105 dBm. I've done it 4 times now, spaced about 5 minutes apart for the first two trys, and then again a few minutes ago, and always the same, a 6 dBm gain in signal strength (the lower the signal strength reading, the stronger the signal)

anyway, while you're probing thru the root files, if there's a file reporting or logging gps antenna strength, or i guess the GPS Test SNR readings serve that purpose, it'd be interesting to see what happens to your results with the cover on & off.

fwiw
[Galaxy S I9000 General] sjdean:
I've seen the screen knock a few points off. You point towards a "green" 40+ Satellite, then turn away from it, watch the signal fall.

Additionally, you'll like this, if I hold the phone in my right hand, cradling the back and move my right index finger just above the volume up control, I get better reception there too.

I've gone up to XXJP3. Time to root.
[Galaxy S I9000 General] enigmameusa:
It's sounds great, but at the moment......
[Galaxy S I9000 General] larryccf:
on another note, that last fix seems to have vaporized in terms of showing satelittes locked - now showing 11 in view, 0 lock

however, even with wireless networks unselected, i'm still showing 21-27 ft accuracy

and when i remove the back cover it dropped to 16 ft accuracy steady (both taken with the back of the phone nearly facing the sky)

if i keep the phone, might cut out the back spare caseback and make a fiberglass panel to fit in it's place - paint it off white in latex paint - under the gel skin it'd never show
[Galaxy S I9000 General] mundano:
With JM2 version I don't have any kind of GPS problem... It's as good as any phone GPS I have user so far.
[Galaxy S I9000 General] sjdean:
:-(

And how are you measuring your GPS performance? What programs, what environment?
[Galaxy S I9000 General] sjdean:
Which fix is that?
[Galaxy S I9000 General] larryccf:
this one - found on the 1st page of the "GPS FIX 101" thread on xda vibrant general forum

STEPS

1 - Disable "Use Wireless Networks" - Settings / Location & Security

2 - Dial *#*#1472365#*#*

3 - Under "Application settings" Change "Operation Mode" to MS Based

4 - Under "SUPL/CP Settings" Change the SERVER & PORT to supl.google.com and port 7276 [ Do not use www. in front of supl]

5 - REBOOT

6 - Turn back on the "User Wireless Networks"

and a few moments ago, started GPS Test and found 13 sats in view, 1-2 locked (fluctuated) but the interesting part, i was inside - first time ever i've got a lock on a sat while in the house - usually, indoors, i can only see 5-8 sats
[Galaxy S I9000 General] Kilack:
Probably because they aren't GPS fixes at all, it is just changing the location servers (agps).
[Galaxy S I9000 General] appelflap:
Simon, do you know if there's a parameter in Jupiter.xml with which one can influence the (default) time gps-programs take between two gps measurements.

I once made a very significant observation.

During a walk in the forest I just couldn't get a fix with my favorite off-road map program OruxMaps. For 20 minutes or so I walked without getting any fix. Then, really tired of this, I decided to do some ad hoc experiments to see if I could get a fix after all. I went into the settings menu of OruxMaps and without any clue :) I changed the time between two GPS measurements from 2 (default value in OruxMaps) to 1 seconds. I left the settings menu, back to the map display and *bam* immediately I got a fix. I just couldn't believe my eyes! The fix was really stable and for at least 2 minutes I was testing the fix the satellites stayed fix. I thought I just had a lucky hit so I decided to go back in the settings menu and changed the time between the measurement back from 1 to 2 sec. and again I couldn't get a fix. I changed it back again to 1 sec. and during a 1,5 hour walk I constantly had a fix.

I think this is very remarkable. The more, because I could reproduce in real time the problem and the solution. Maybe it is possible to play with this time parameter in jupiter.xml. Another parameter that could be worthwhile is the distance between two gps measurements.

Best regards,

Paul

PS (edit: something totally different :) ): yesterday I had a constant fix for 4(!) hours in CoPilot during a drive through the country. This was on the JM2 firmware, which I flashed yesterday..
[Galaxy S I9000 General] appelflap:
13 sats in view?! Are you sure? That's really something, I never saw more than 11.
[Galaxy S I9000 General] amar_raavi:
i did the same and had similar results. Fix is fast and seen most of the bars turn green. First time my tracks worked perfectly without jumping around all over the place.
[Galaxy S I9000 General] sjdean:
Not that I know of unfortunately. Im not an expert on the file format either, though Im guessing I've probably hacked it most of all.

I've tried changing BrcmRFwildBase, BrcmRFclkDiv, anBrcmRFclkRefHz to different values without any success. I've even tried changing the SUPL server listed to detrimental results.

I feel at this point there's either some init string sent from the Samsung system to the driver, or the Broadcom supplied driver is just wrong. Whatever settings we need, I don't think we can change them through jupiter.xml or anywhere else. At least not yet.

Be interested if we could get a program that could write an NMEA string to the GPS serial port to tell it to do something else...

Cya

Simon
[Galaxy S I9000 General] larryccf:
yeah, and now that you mention it, 11-12 is the most i'd seen before that sampling
[Galaxy S I9000 General] appelflap:
So it would be possible to program the GPS by sending NMEA strings to its serial port?! Well, that's something I definitely going to look in to. Thanks.
[Galaxy S I9000 General] appelflap:
A screen dump of those 13 sats would have been great. A "shock" for us all :)
[Galaxy S I9000 General] sjdean:
As far as I can gather, it is just a serial port. There are a few instances I've read off from that website I mentioned previously (I'll dig it out later) about sending command to it.

Of course, I do not know what the command set is for BCM4571.

And what's wrong with people, even after I get the jupiter.xml which refers to 4571, the log files which says it sees a 4571, some people still keep insisting on saying it has the 20751 (or whatever it is). Grrr. :mad:

Cya

Simon
[Galaxy S I9000 General] appelflap:
I overlooked the message from you in which you were scrutinizing the NMEA data of the GPS .. And you're right, we need to know the command set for the BCM4571, because in the link you refered to, it is stated that: "While some receivers accept standard NMEA input this can only be used to update a waypoint or similar task and not to send a command to the unit. Proprietary input sentences could be used to send commands."

We need to know those proprietary commands (if the chip supports them, that is)

Maybe we can look at what is known in the iphone community about the iPhone 4.0 GPS chip. I've read that the iPhone 4 is using a BCM4750 chip. That looks pretty identical to the BCM4751 (in code that is :) )

Maybe a little command to reset the GPS so now and then when it is going astray can be enough for now (till Samsung fixed the GPS of course)? A few days ago I couldn't get a fix, I rebooted the SGS and after restarting the program I used (GPS Status) I immediately got a fix. (one of those strange observations)
[Galaxy S I9000 General] mundano:
I'm testing it with real world use as navigation system while driving. And with JM2 firmware it is as good as my old Nokia N95, but with a 4" screen and mutch faster software.

I don't have any kind of loss of accuracy problems.
[Galaxy S I9000 General] fredphoesh:
GPS NAVIGATION vs GOOGLE STAR MAPS

Hello guys,

My experience is

!/ very useable Google Navigation (tried and worked perfectly in my car 4/4 times.

2/ HORRIBLE Google Star Maps... used to work really well with my Hero, now it is completely unuseable, a joke, I can turn right around and the same stars jerk about with no relationship to the way I am facing.

Odd hey?

Mark, UK (Orange)
[Galaxy S I9000 General] sjdean:
Install MyTracks and see how accurately it tracks the road.

Yes, by and large, I think it is just about OK for road driving because of snap to streets.

But just try MyTracks and see how many peoples houses it thinks you drive into.
[Galaxy S I9000 General] veper:
Seems Engadget finally started to mention the GPS problem:

http://mobile.engadget.com/2010/08/02/wheres-the-gps-fix-for-the-samsung-vibrant-and-captivate/
[Galaxy S I9000 General] sjdean:
So it could be Samsung after all, not Broadcom.

Someone on the dev forum has prompted me to scan through the NMEA logs a little more. Interesting.

I have seen a 9 satellite fixes a few times:

$928439I <SKFNAV> m_stSKF.rt [52.427664, -1.856145, 156],[0.0m/s, 0deg] dts:8ms 8.487334
%928441E GL_NMEA[$GPGGA,101512.00,5225.660399,N,00151.368988,W,1,09,1.0,97.7,M,49.1,M,,*47
%928457I GL_NMEA[$PGLOR,STA,101512.00,0.008,0.000,419,1,10,0,PWR,D*0D
%928458I GL_NMEA[$PGLOR,SAT,15,030,1F,27,022,1F,09,020,15,26,034,1F,18,023,11,28,025,1F,17,028,1F,22,019,11,12,017,11*4D
%928464I GL_NMEA[$PGLOR,SIO,TxERR,0,RxERR,0,TxCNT,308,RxCNT,1920,DTMS,992,DTIN,1,DTOUT,278*77
%928465E GL_NMEA[$GPGSV,3,1,12,15,73,167,31,27,70,276,23,09,53,268,20,26,47,133,34*7A
%928469E GL_NMEA[$GPGSV,3,2,12,18,37,283,23,28,30,050,27,17,24,096,29,22,19,317,19*76
%928473E GL_NMEA[$GPGSV,3,3,12,12,10,207,17,39,25,147,16,33,28,197,,24,05,323,*77
%928477E GL_NMEA[$GPGSA,A,3,09,12,15,17,18,22,26,27,28,,,,2.1,1.6,1.4*39
%928481E GL_NMEA[$PGLOR,FIX,1.0*3E
%928484E GL_NMEA[$GPRMC,101512.00,A,5225.660399,N,00151.368988,W,000.0,,310710,,,A*62
LBS_I: API: gllbs_gps_notify_position(52.427673, -1.856150)
LBS_I: CB: RIL request 3

This is interesting.

15 SnR 31	18 SnR 23	12 SnR 17

27 SnR 23	28 SnR 27	39 SnR 16

09 SnR 20	17 SnR 29	33 SnR ??

26 SnR 34	22 SnR 19	24 SnR ??

Automatic, 3D fix, using 09, 12, 15, 17, 18, 22, 26, 27, 28

GPS Test won't show us satellites < 20 SnR, but here, the GGA line show 09 satellites being tracked, and GSA shows 9 satellite fixes, including 22 with an SnR of 19 and 12 with an SnR of 17. And look at the Horizontal dilution of Precision - 1.0!

Oooh. Not quite sure about the correlation between the HDOP on the GPGGA and the HDOP on the GPGSA. But its interesting that the underlying system thinks its locking onto 9 satellites.

I don't know whether this gives me hope or not. On one hand, it sounds like a simple fix. On the other hand, if its so simple, why hasn't it been fixed?

Cya

Simon
[Galaxy S I9000 General] The.Opethian:
Wow, the results are a mixed bag. Samsung needs to hire someone or a team whose sole purpose is sifting through forums like these.
[Galaxy S I9000 General] appelflap:
Interesting, but what program or method are you using to read the NMEA strings? Are you using GPS Nmea monitor of the same developer as the developer of GPS Test?

When I look at the android api, the most simple and straightforward way to get Nmea strings is to create a GpsStatus.NmeaListener which interfaces with an instance of LocationManager. (see: android.location package)

This same LocationManager is used to get interpreted info like latitude, altitude, accuracy, speed, GPS fixes etc etc, with other listeners. So I don't understand why one can see totally different data when using different Listeners for the same class.
[Galaxy S I9000 General] larryccf:
now that you mention what you're reading from GPS Test and from the files you're exploring, i meant to ask how accurate or complete you thought the GPS test program's reporting was

even when GPS test was not showing any sats locked, or showing 3 locked and accuracy of 21 feet, google maps were showing me exactly where i was standing - in front of the house another street "T"s into my street and wherever i stood, in the center or off to one side, google located me exact and i mean exact, had to be much less than 10 ft, while GPS Test was showing 21 - 27 feet
[Galaxy S I9000 General] Kilack:
Hi Simon,

I read through the raw data you generated and it is great to see it using snr's of less than 20 and also fixes of 9 satellites.

Had to look up the format of the raw data but easy enough format to read.

Anyway, what I don't get is why gpstest isnt displaying the satt's with less than 20, is that just an app issue?

and why do you come back to thinking its a samsung issue when you can see it getting pretty good data back from the chip?

Where are the logs located? I am quite interested in seeing what is happening on mine.

thx
[Galaxy S I9000 General] sjdean:
Im actually looking at the raw log files after enabling logging through jupiter.xml.

Some interesting things in there, such as lines that enable low power:

#180442D ->GlPePwrStateMgr::SteadyNormalMode(PE2PE_LP_ENABLE_LOW_PWR,0)

#180442D ->GlPePwrStateMgr::NormalMode(PE2PE_LP_ENABLE_LOW_PWR,0)

Difficult to say. I think some programs perhaps have the ability to read and interpret raw NMEA data. Then there are other programs which seem to be able to only get the information from the Location Provider.

Someone showed me the following link which suggests Samsung will have provided a libgps.so which links through to the underlying GPS system.

http://pdk.android.com/online-pdk/guide/gps.html

Then there appears that there may be a third class of program, one that reads NMEA data to say "you have a fix on 10 satellites" but then listens to the android location provider to determine its accuracy and position.

Im not sure it is an app issue. Right from the beginning I've compared to a HTC Desire which locks onto 10 satellites compared to my 6, and uses SnR's < 20.

I've never seen my accuracy drop below 16ft, whereas the HTC Desire achieved 16ft.

http://picasaweb.google.com/sjdean/Shared#5486828562980341842

The reason I think it isn't the app, is because first and foremost, the app works on the HTC Desire. As far as I know, the GPS effectively reports its information via a serial port, so if we see good NMEA information, then the problem can't be the GPS Receiver.

The problem appears to be between the app and the driver. The problem appears to be in the way the data is interpreted. Where, I can't be sure, but it could well be libgps.so. I think this is a Samsung file.

In terms of finding logs, you would need to gain root and edit jupiter.xml under /system/etc and find the line which says cLogEnabled="false" and change it to true.

acLogDirectory="/sdcard/gps/log/" specifies the log path.
[Galaxy S I9000 General] Kilack:
Yeah I was going to say it would be nice to have a program that we know only uses the raw NMEA data and see what kind of accuracy we see there, a mytracks version using nmea data would be great..

So its definitely looking like a non hardware issue then, good news I guess, should be a question of when they fix it not whether then can.. :)
[Galaxy S I9000 General] appelflap:
aha, great ... aren't this specific nmea command strings for the BC chip?

Very interesting hypthesis. If i've the time I will compare a log generate by setting a flag in jupiter.xml and a log generated by an app called Nmea monitor and compare the two. It could very well be that there's a substantial difference bewteen these two and that the log of the nmea monitor is in sync with the output of GPS Test (from the same developer) whereas the raw nmea log file is not.
[Galaxy S I9000 General] ghosty_uk:
i finally tried this out while driving today and my good its prettey bad, ok so the gps is accurat when using google navi, but my tracks, i was nearly in stiches how bad it actually was, if somerone can tell me how to post it up i will do.

next question is, where will the fix for this issue come from first, the dev team at samsung or the people on here.
[Galaxy S I9000 General] Kilack:
There are options in mytracks to share it from there I think.

It allows you to upload it etc.
[Galaxy S I9000 General] ghosty_uk:
this is more or less the same test i did with my new SGS and my old SGS, both side by side, and running the lbn test menu. old one got 5 sats fixed 1, new one got 9-11 and fixed 7.
[Galaxy S I9000 General] boomerbubba:
The GPS NMEA Monitor app seems promising. But I was not able to get it to display anything on my Samsung Galaxy Vibrant. If you can get it working, please report back.
[Galaxy S I9000 General] Kilack:
So the terrible track you just got, was that on the new sgs?
[Galaxy S I9000 General] boomerbubba:
One way to do that is:

1) Enable logging as sjdean has done. (I gather this requires root.)

2) Capture a test track using the My Tracks utility. Save it as KML.

3) Parse the NMEA log that was captured contemporaneously, and write the polyline as a track in another KML file.

4) Compare the two tracks in any tool that imports KML. Google Earth is handy for merging the two tracks into a single file (with different colors) and displaying both overlaid. The merged file also could be uploaded to Google My Maps website for sharing.

I can't do all this because I don't have root. (Also, I have a Samsung Galaxy Vibrant, so I could only test on that platform anyway.) But if someone wants to capture these files, I could help with steps 3 and 4.

The only variables being compared graphically that way would be the geographic tracks themselves, not the satellite detail such as SNR. I don't think My Tracks captures that.

EDIT: It also would be pretty easy to do this directly. There are utilities out there such as NMEA2KML or GPSBabel that will convert the NMEA sentences to KML. Then just edit that and the My Tracks KML export together within Google Earth.
[Galaxy S I9000 General] Rawat:
Finally. I tipped them a few times months ago, even gave them a whole bunch of links to people experiencing the issues. Seems like they just weren't bothered about it 'till they learnt it affected their US models too :mad:
[Galaxy S I9000 General] foxbat121:
Interestly, I came to the same conclusion today after comparing the built-in lbs test menu and Navigator or other GSP mapping apps. Using the internal GPS test app, I can quickly archive lock and saw 10+ satellites and lock on to 6+ of them most of the time with accuracy of 10m and 5m most of the time. However, with other apps, not only it took longer to accquire lock, the accuacy were mostly like 30+ m. So, it leads to to believe this is purely a software issue, probably a Samsung driver that outputs wrong data to Android system where apps get their location information from.
[Galaxy S I9000 General] appelflap:
Strange, it works "out of the box" on my Galaxy.

Brilliant idea.
[Galaxy S I9000 General] appelflap:
If there's a difference between the low level, raw nmea data and the data that is captured by the Android API one could ask if the Galaxy S is really Android 2.1 compatible and may call itself a Android Phone :D

http://static.googleusercontent.com/external_content/untrusted_dlcp/source.android.com/nl//compatibility/android-2.1-cdd.pdf

In that case, if the issue isn't solved by Samsung (which I don't assume, because its a reliable company), there is always a possibility to force them legally.

Just speculation.
[Galaxy S I9000 General] Tulips:
lol... i just found a "nice" video clip of the fantastic gps samsung have provided us

http://www.vimeo.com/12583232 :eek:
[Galaxy S I9000 General] padlad:
Its been nearly three weeks now, looks like Samsung have been talking out of their arses/misleading/bullsh*ting as usual, some things never change! I feel sorry for Clove, a good company chasing up Samsung on behalf of their customers only to be told a load of '**** and bull'. Shame on you Samsung!
[Galaxy S I9000 General] appelflap:
great ! The other videos of this navigation artist are also great. For example, this one:

http://www.vimeo.com/12582629

The navigator finds a route (so it has a fix) but during the drive the navigator thinks the car stands still. :D