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All Things GPS

S

SamsungVibrant

Android Expert
First of all congratulations everybody. I am soooo excited for each and every one of you. Seriously, I have a big smile on my face because I know that excitement, that joy you all are feeling. You won't be putting your phone down for days, I GUARANTEE IT! You guys seriously just purchased the most kick ass Android device, along with the rest of the Galaxy S phones!

The Vibrant and Captivate users are watching closely. Samsung has promised us a GPS optimization, and presumably your Epic already has it. So you guys are our life line right now.

For those of you who will be testing out your GPS in the next few days, I'd like to make a few comments, so that we can get accurate GPS testing, to determine if the phone is actually using satellites like it should, or depends instead heavily on less accurate cell phone towers to determine your location, which means the GPS is still busted on these phones.

Okay, so here it goes. When testing your GPS, "Use Wireless Locations" should be turned off. Settings>location & security>Use wireless networks...make sure its UNCHECKED.

Read the note right under it, it says "See location in applications(such as Maps) using wireless networks." If you put a check mark next to this, and turn this ON, then how will you ever know if the phone is functionally using the satellites. This is the big question with the phone, can it use and lock onto satellites or is Samsung hoping we use less accurate cell towers. Samsung hopes you have this on. I ask that you keep this unchecked, this is the only way to truly test the Satellite usage.

Further, by checking this, you are allowing Google to collect location data, even when no applications are running, they say its anonymous, but you never know.

So uncheck "Use Wireless Networks," restart your phone, make sure this is still unchecked, power up Google Maps, and go for a good long drive. Then please share your real world results. Including, how quickly it located you, was the location correct, how wide of a blue circle is there around your location, did the phone ever drop the GPS signal, etc. No 2 min drives, you really need to drive around a lot to dependably test this.

You can also download "GPS Test" from the Android Market, it will show you how many satellites your phone views, versus how many satellites are locked in. You need 4 LOCKED on satellites to get a true 3D positional lock that includes x,y,z,t. GPS test also shows your accuracy in ft, up in the upper right corner. Good accuracy is anything less than 10 ft. I have phones that get 5ft accuracy, the best accuracy I can get with my Vibrant is 40ft. Please report this number also. If you have time, upload a screen shot of your GPS test, or just take a pic of your phone running the GPS test, upload it and share your results.

You can also use the built in native GPS test. It is virtually the same as the GPS TEST program above, it's just not a pretty visual interface.
Go to your phones dialer, as if you are making a phone call, and dial in *#1472365# Then click on "get position test." (edit on the code above, this should work, thanks to user nucleartx)
This test will show you your longitude and latitude, you can then enter this into Google maps to see how accurately it located you. It gives you accuracy in meters, convert to feet by multiplying the number given in meters by 3.28, you will now have your accuracy in ft.
The native built in test will show you have many satellites it has in view, the satellites that it actually locks onto will have an asterisk next to it. Please report both these numbers. Remember you need 4 locked on satellites for true precise 3D positioning.

I'm really interested to hear from prior smart-phone Android users, because these users will be able to make a direct comparison of the GPS to prior phones.

Thanks, and enjoy your phone!
 
Another thing to watch for is whether the reported accuracy is real. For example, GPS Test may report that the Android GPS has a theoretical accuracy of 20 feet. Is your actual position really within that circle?

In addition to testing satellite locks with the GPS Test or GPS Status utility, test the accuracy by recording tracks with the My Tracks app. Then you can upload the tracks to Google's My Maps site and share a link with all of us so we can judge that accuracy for ourselves. Anecdotal impressions, good or bad, add little value to the discussion.

Test both driving and walking tracks, the latter being the tougher test. One problem with driving tracks is the the low-level GPS on Galaxy S phones seems to apply some smoothing or interpolating algrorithms, in which case the rapid vehicle motion tends to obscure the errors. (The software just seems to predict where the next point should be based on the motion.) Where this kind of algorithm tends to fall down is on quick turns and corners, where the track can veer off-course. Also, when stopped, the GPS might drift.

Walking tracks are even more rigorous tests.

Also, when standing still, does the cursor drift around?

In the case of all tracks, it is best if you have a known benchmark device -- I use my trusty old G1, which has excellent GPS performance -- to compare the tracks side by side. Because although no GPS is perfect, it is useful to compare this performance to what is possible.

The worst software of all to use for GPS testing is a dedicated street navigation app. These programs masks the errors even further by snapping the cursor to the closest road. Unfortunately, most "reviews" just use such apps, and hence are not worth much.

BTW, I won't have my Epic until tomorrow. But I was expecting to see some new utility called GpsSetup. Has anyone seen any sign of such a utility on their new phone?
 
But thats part of the whole problem.. youre not supposed to have to turn the data part off. The phone is supposed to be able to triangulate your location off of data if there are no satellites available.. thats the issue.
 
brownhornet said:
But thats part of the whole problem.. youre not supposed to have to turn the data part off. The phone is supposed to be able to triangulate your location off of data if there are no satellites available.. thats the issue.
Click to expand...

Wrong. Any dumb feature phone can get a rough fix from triangulating data. High-end smartphones like the Galaxy S have sophisticated GPS satellite receivers that really can be used in several modes -- pure satellite (called Standalone oir Autonomous mode), pure cell tower triangulation (called MS assisted), which is the worst of all but can often work indoors, and MS Based, which is a hybrid that uses network data to accelerate the time of the first fix, then satellites to get the final fix.

The Samsung Galaxy S phones have had multiple bugs in all this. But one underlying problem is the the satellite fix is neiether stable not accurate. The point of turning off the network data is to isolate the satellite receiver's performance for testing.
 
quasi13 said:
I believe this setting is unchecked by default on Epics in case you weren't aware.
Click to expand...
Yes I am very well aware. However, Samsung is telling people to turn it on. They even told engadet to tun it on....this resulted in engadet making a false statement in their epic review....they basically said turning on wireless networks gets rid of the GPS problem. Many captivate and vibrant owners quickly let engadget know of their error and engadget released a new statement. The point of the thread is...Don turn it on...leave it off to test GPS.
 
brownhornet said:
But thats part of the whole problem.. youre not supposed to have to turn the data part off. The phone is supposed to be able to triangulate your location off of data if there are no satellites available.. thats the issue.
Click to expand...
Incorrect,. Please don't post samsung spin on a serious and sober thread. That is NOT the issue, that is one small issue.

We are talking about outdoors testing and there are always satellites available. The question is about how fast it is getting them, how well it is holding them and how well it is calculating position from them

Adrift said:
With assistance off, I have 8 in view, 8 in use. Accuracy of 98' though.
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that shows some kind of problem, you should be getting <10 meters maximum with over 6 birds
 
brownhornet said:
But thats part of the whole problem.. youre not supposed to have to turn the data part off. The phone is supposed to be able to triangulate your location off of data if there are no satellites available.. thats the issue.
Click to expand...


Shouldn't your statement be in reverse. Cell phone towers do not exist everywhere, but satellites are always up in the sky. If you are in an area with no cell signal, you expect GPS to work by using satellites. I mean isn't that what GPS really comes down to, finding your location via satellites.

Further, for people who use navigation programs that include preloaded maps, meaning they don't depend on a cell phone signal downloading the map, these people are even more dependent on satellites.


If all the map data is loaded in your phone, and you are driving around in a remote area, and you enter a no cell phone zone, you are lost, running out of gas, and helpless, I would hope that you agree that at this moment you would hope that the GPS is picking up and using satellite signals.

Furthermore, not everyone uses GPS exclusively in the car. Even google maps offers an on foot option. Many people go hiking with their phones and use GPS. When in a big city like new york you walk around on foot. In these cases, if the phone is getting poor accuracy because it can't use sattelites properly, then essentially the GPS is useless when on foot. There is no way you can use a GPS the way it's meant to be used on foot, when you are getting horrible accuracy.
 
Are you guys simply using SprintNav? Then have it show your current location on the map? If so, works fine for me, and I'm indoors and in the boonies!
 
boomerbubba said:
Wrong. Any dumb feature phone can get a rough fix from triangulating data. High-end smartphones like the Galaxy S have sophisticated GPS satellite receivers that really can be used in several modes -- pure satellite (called Standalone oir Autonomous mode), pure cell tower triangulation (called MS assisted), which is the worst of all but can often work indoors, and MS Based, which is a hybrid that uses network data to accelerate the time of the first fix, then satellites to get the final fix.

The Samsung Galaxy S phones have had multiple bugs in all this. But one underlying problem is the the satellite fix is neiether stable not accurate. The point of turning off the network data is to isolate the satellite receiver's performance for testing.
Click to expand...


Out of all the smart phones ive had ive NEVER had to turn cellular location off for the gps to work right. But if you say so.
 
SamsungVibrant said:
Shouldn't your statement be in reverse. Cell phone towers do not exist everywhere, but satellites are always up in the sky. If you are in an area with no cell signal, you expect GPS to work by using satellites. I mean isn't that what GPS really comes down to, finding your location via satellites.

Further, for people who use navigation programs that include preloaded maps, meaning they don't depend on a cell phone signal downloading the map, these people are even more dependent on satellites.


If all the map data is loaded in your phone, and you are driving around in a remote area, and you enter a no cell phone zone, you are lost, running out of gas, and helpless, I would hope that you agree that at this moment you would hope that the GPS is picking up and using satellite signals.

Furthermore, not everyone uses GPS exclusively in the car. Even google maps offers an on foot option. Many people go hiking with their phones and use GPS. When in a big city like new york you walk around on foot. In these cases, if the phone is getting poor accuracy because it can't use sattelites properly, then essentially the GPS is useless when on foot. There is no way you can use a GPS the way it's meant to be used on foot, when you are getting horrible accuracy.
Click to expand...

When did I say that the GPS isnt supposed to be the default option? I think youre reading too much into what I said. I said with smartphones you're NOT supposed to have to turn that option off for the GPS to work right.. and you arent. I've never had to do it with any phone ive owned. Dont have to do it with the evo either.
 
i was in the car and needed navigation to work...couldnt get a gsp lock, it just stayed searching. pretty pissed, my evo worked flawlessly
 
brownhornet said:
Out of all the smart phones ive had ive NEVER had to turn cellular location off for the gps to work right. But if you say so.
Click to expand...

The point is that when you are using cellular location, you aren't really using the GPS, which is a satellite-based system. The cellular location is just a crude workaround.

The problem with the Galaxy S family is that the satellite-based GPS receiver is broken. So the idea is to test whether it got fixed on the Epic.
 
brownhornet said:
When did I say that the GPS isnt supposed to be the default option? I think youre reading too much into what I said. I said with smartphones you're NOT supposed to have to turn that option off for the GPS to work right.. and you arent. I've never had to do it with any phone ive owned. Dont have to do it with the evo either.
Click to expand...

with all do respect, you are not expressing yourself clearly, and I'm not understanding you, I think you may also be a little confused.

You said: "with smartphones you're NOT supposed to have to turn that option off for GPS to work right..and you aren't"


I never said you were supose to turn "use wireless networks" off for GPS to work right. I said the contrary. I said, you need to have that off, that way you can test the satellite performance. Otherwise, leaving it on, you are getting assistence from cell phone towers. Thus, as a result, one would not know if GPS performance in the real world was based upon network or satellite.

Is that more clear? I don't know how else to explain it. Please re-read my original post, and re-read what you wrote. There is some misunderstanding, or I'm just not understanding your statements in the structure they are written.

EDIT: BTW, just to clarify. You shouldn't have to turn that option ON for GPS to work either. This is exactly the problem. GPS on Vibrant/Captive and world release versions of Galaxy S DO NOT WORK unless they use cell towers with that option ON. Samsung even told engadget to turn it on, but you shouldn't have to have that ON. Haven't it on is a disguise, a mask to hide a potential GPS problem.

The point of this thread was to find out if Samsung fixed the problem with firmware on the new Epic, meaning there is hope for Captivate/Vibrant/ and other Galaxy S users around the world.
 
boomerbubba said:
The problem with the Galaxy S family is that the satellite-based GPS receiver is broken. So the idea is to test whether it got fixed on the Epic.
Click to expand...

Well, judging from the "Is your GPS working" poll, and my own GPS test results from earlier, things are looking promising for the Epic.
 
boomerbubba said:
The point is that when you are using cellular location, you aren't really using the GPS, which is a satellite-based system. The cellular location is just a crude workaround.

The problem with the Galaxy S family is that the satellite-based GPS receiver is broken. So the idea is to test whether it got fixed on the Epic.
Click to expand...

Thank you, exactly what boomerbubba said.
 
SamsungVibrant said:
with all do respect, you are not expressing yourself clearly, and I'm not understanding you, I think you may also be a little confused.

You said: "with smartphones you're NOT supposed to have to turn that option off for GPS to work right..and you aren't"


I never said you were supose to turn "use wireless networks" off for GPS to work right. I said the contrary. I said, you need to have that off, that way you can test the satellite performance. Otherwise, leaving it on, you are getting assistence from cell phone towers. Thus, as a result, one would not know if GPS performance in the real world was based upon network or satellite.

Is that more clear? I don't know how else to explain it. Please re-read my original post, and re-read what you wrote. There is some misunderstanding, or I'm just not understanding your statements in the structure they are written.
Click to expand...

i'm with you lol i know how it works :p
 
It works, not as well as it should, but better than I thought it might. We'll see if it is useful for navigation tomorrow.

Outdoors, with network triangulation disabled:

8 satellites locked, 8 in use, SNR was between 10 and 30 for all satellites.

Accuracy was at +/- 98.4 feet.

...

For comparison ...

An iPhone 4 using Motion X GPS reports 33 feet, and is certainly closer on the map than the Epic is. I believe Motion X GPS reports discrete accuracy "blocks" rather than infinitely variable values (I stand to be corrected), and they are something like 33 feet, 56 feet, 98 feet, 156 feet and so on. So 33 feet could be right on the cusp of rolling up to 56 feet.

A Garmin Rino 530HCx with just 3 birds locked reports +/- 55ft and with 8 locks comes down to 10 feet.

All tested in the same location.

NOTE: Do not test two powered-up GPS receivers in close proximity to each other (only have one unit on at a time) as they can affect each other.
 
I walked around my apartment complex using My Tracks, with an accuracy of 98 feet, I was expecting the results to be much worse. It tracked me very accurately only being off my true track a few times and never more than by 10 feet or so.

I find the GPS, on my device, to be very good. Not great, but very good especially compared to my moment.
 
It seems we're getting good and quick GPS locks from multiple Sats, but we're all reporting the same accuracy number, which is 98 feet. I got 98 feet myself. Not much deviation from the 98 number (meaning no one is getting higher nor lower than 98).
 
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