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GPS is incredibly inaccurate on 3GS..

I've been a longtime macrumors reader but I just noticed something regarding the gps. I, too, was having a very inaccurate reading when using Maps as well as MotionX pro (which I bought just to see if it would 'fix' the problem). Well, I kept getting the same issue (about 1/2 mile off). Ironically when I switched to wifi (off of 3G), I tried Maps again: It showed the original blue dot (off 1/2 mile) and then repositioned to my 'exact' location (very accurate). I think the problem is the 3G connection that is throwing off my position. Even the MotionX program repositioned to the exact position. I then took off wifi and went back to 3G and the results.... back to the wrong position! Same with MotionX.

So the problem (at least with me) is the 3G connection. I just tested my wife's iphone (the no GPS 1st gen. which only does triangulation; of course she got my old phone :) ), and with Maps our positioning location was WAAAAY off (not even close!), but I know that accuracy was been better in the past on this phone. I duplicated the results so I know it wasn't a fluke.

Of course, we've had extremely stormy weather on the east coast so maybe that has something to do with it?

btw, I live near NYC and we have a very strong 3G network here (at least it seems it).

Long story short: if you have a wifi connection, try that over 3G and see if that makes a difference. It did for me!
 
Is it possible that it's the 3gs launch that is throwing this off? I remember that gps accuracy was a problem with the original 3g right around launch. I just assumed that it was a software update that eventually fixed this but maybe it was that AT&T eventually beefed up the network a little or the hype died down. Just a theory, since the speed of the gps lock is largely dependent on the cell network location since it's agps.
 
I have found it to be quite accurate but there are always exceptions for some reason

There are a few spots near me where the GPS can't find me though it is only a few times in the last year
 
Resist said:
You are correct, but I still think the military gets slightly better accuracy on their GPS devices. While we get accuracy within 10's of feet, I am sure they get it within inches.
Click to expand...

Military does not track within inches, are you tossing a dart at some answer chart on a wall? Clearly you haven't researched the topic at all and are totally unaware of how GPS work (Both Civilian and Military).

I think this is one of the better answers found on the topic, question being do civilian and military use the same GPS satelites?

"The answer is yes. The GPS is a constellation (group of satellites), 24 overall, that are in 12-hour orbits about the earth. They are synchronised so that it's possible to get signals from up to 12 of them. Four are needed to get one's location, but more signals means greater accuracy.

Up until May 2000, there were the civilian signals and the military signals. Basically, the military signals required special components to be received, thus it was limited. The civilian signals were not as precise, usually allowing for about a 30 metre (100 feet) accuracy.

During the Clinton Administration, they decided that the civilian application of GPS outweighed the risks involved with precise signals, so on 1 May 2000 the select availability was dropped, and with a small update, civilian GPS receivers could utilise the military signals, giving an accuracy of roughly 3 metres (10 feet)."
 
bossxii said:
Up until May 2000, there were the civilian signals and the military signals. Basically, the military signals required special components to be received, thus it was limited.
Click to expand...

Having been in the military until 2006, I can tell you this is not completely accurate. We had to get encryption keys loaded on our PLGRs before use.

There is a specific encrypted military signal from each satellite to ensure that the GPS signal is authentic and that requires special components. But, no - it doesn't affect accuracy.
 
If our gps is a few miles off, do you guys think this is something worth calling apple or bringing to an apple store over? or should we wait for a little while to see if its just because of the release.
 
Resist said:
If you were to take a pin and stick it on a map, the point is where you are. This is an exact location, not an area within a circle of accuracy.
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Yes, but how big is the map? If the map is of the world, that pin could very well cover your entire state.
 
Diode said:
Remember google maps might be off and not the GPS.

Testing with google maps is NOT a good way to test accuracy.
Click to expand...

I'm still not sure about google maps. As I said above, when disabling 3G and using wifi the positioning blue dot maneuvers to a more accurate position. The map may be off, but I'm definitely getting a more incorrect position when either 3G or EDGE is activated. Hopefully once a turn-by-turn app is available there can be a calibration tool (using the app/GPS to determine position, then dragging the blue pin to a precise location and calibrate the map to the adjusted position. Could be possible...

I know that at this point relying on the GPS for turn-by-turn couldn't (at least where I live) accurate enough to be useful.
 
Mine seems very accurate. It also locks onto the sat much faster. I also love the feature to point the map in the direction traveled.

Good job Apple!!
 
Is it just me, or is the GPS blindly innacurate?

If I turn my GPS on my iPhone 3G S it will generally say I am driving through grass on the side of the road. Or, if I am sitting still in my house, it says I am in my neighbor's house. Also, if I turn on a road the dot continues moving straight through the intersection to where I am not, and 5 seconds later pops up where I actually turned.

Is this normal or do I need to get it fixed?
 
Mine is pin point accurate as is the compass...it even found me despite being in my flat on the 2nd floor which my 3G could never do
 
Diode said:
Remember google maps might be off and not the GPS.

Testing with google maps is NOT a good way to test accuracy.
Click to expand...

I have to second this. Google, for some reason or another, does NOT have Avon, IN mapped out too well. Tried to find a dunkin donuts in Avon one time, it had it damn near to Danville (way west of Avon). Several other locations in Avon were off by several miles (again close to Danville). :confused:
 
Sometimes the blue dot wanders off across the street and down a few houses from where I'm standing with my iPhone.

Sometimes the blue dot is so bloody accurate that I can walk around my car parked in my driveway, and the blue dot will follow me around the car's overhead image as it shows in Google maps (assuming I parked it the same spot).

Must be the luck of what or how many satellites are currently in view overhead or something.
 
Mine is ~ 500 meters off

duelingdragons said:
Maps is telling me that I'm about 2 miles away from my actual location. I've tried in a few different places.

Anyone else having this problem? :(
Click to expand...

Yea..
I'm havin this problem too..
Tried in middle of the road at the back of my house
resetting the phone got it accurate for once
but it got inaccurate again
(tried turnin on & off airplane mode)
then maps again

I have pin my house exact location on map
when I'm getting direction to my house from the current location (which was the open road back of my house)

it shows I'm 500m off..
I guess it showed location based on the cell tower or something

my garmin 255w display an accurate gps loc
 
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