Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Does iPhone have GPS or not???

V

vbmike73

macrumors regular
Original poster
Nov 8, 2008
149
3
I've been reading some other posts, all about the GPS and A-GPS or Assisted GPS, which basically assists the GPS receiver in acquiring your position quicker. So if that's the case, then how could a position be off by miles? That makes me think that it's not GPS at all, but rather going off cell towers and wifi signals. And what if I'm in an area where I have no cell covereage period? Can I find my position? And a side question, I'm asking all this because I want to be able to find my lat/lon at any patricular place. So I'm curious... if it is a true GPS, then why is there no way (that I have found) to obtain your lat/lon from a native iPhone app? I thought maybe the compass would, but I don't see it, unless it has something to do with the location arrow on the bottom left that does not allow me to select it. And if there is not a way to obtain this via a native iPhone app, are there free ones out there which actuall work? The one I tried was GeoMarker, but that gave me lat/lon at least 3 miles away.

A lot of questions I know, but any help is appreciated.
 
Fidget08

Fidget08

macrumors regular
Jun 14, 2010
149
218
It has VERY good gps! It found me to within 2 inches... Ok I kid but it was more like 20 feet. Its so amazing! Better than my old blackberry storm.. That thing could find me within 300 yards!
 
V

vbmike73

macrumors regular
Original poster
Nov 8, 2008
149
3
noah82 said:
Of course it has gps. How do you think Google maps and navigation programs work?
Click to expand...

Thanks for that VERY HELPFUL answer!

My question was related to how much of a true GPS it is.

I'm not trying to be difficult here, but I really thought after typing up a detailed, LEGITIMATE question that I might get some useful replies. Instead I get the obvious pointed out to me, and a link to the Apple page where it actually has the words "Assisted GPS". That's great, seeing that I already stated it has Assisted GPS. If it were an actual Apple definition of A-GPS then that would be helpful.

MY GPS is showing me off by 3+ miles. So therefore, one can only assume that the final determination of my location is NOT by GPS. Why do you think there are so many issues with Find My iPhone and people saying it's not showing where they are? That shows me off by 3+ miles sometimes too. Something's going on here. It's not just my phone.
 
-aggie-

-aggie-

macrumors P6
Jun 19, 2009
16,793
51
Where bunnies are welcome.
As stated, EDGE/3G/wifi assist the iPhone in finding the satellite quicker, so GPS can track you. If you're that far off, it means the phone never found the satellite and your GPS is essentially not working. You can try calibrating the GPS by resetting network settings and then turning on Location Services, but from what I've seen, you probably have a faulty GPS.


^^^^^
Hopefully, I answered your question. It is true GPS.
 
treyjustice

treyjustice

macrumors 65816
Jun 14, 2009
1,252
141
TX
vbmike73 said:
I've been reading some other posts, all about the GPS and A-GPS or Assisted GPS, which basically assists the GPS receiver in acquiring your position quicker. So if that's the case, then how could a position be off by miles? That makes me think that it's not GPS at all, but rather going off cell towers and wifi signals. And what if I'm in an area where I have no cell covereage period? Can I find my position? And a side question, I'm asking all this because I want to be able to find my lat/lon at any patricular place. So I'm curious... if it is a true GPS, then why is there no way (that I have found) to obtain your lat/lon from a native iPhone app? I thought maybe the compass would, but I don't see it, unless it has something to do with the location arrow on the bottom left that does not allow me to select it. And if there is not a way to obtain this via a native iPhone app, are there free ones out there which actuall work? The one I tried was GeoMarker, but that gave me lat/lon at least 3 miles away.

A lot of questions I know, but any help is appreciated.
Click to expand...

you can get your lat and lon from the compass app.

that is using the digital compass inside it
 
Y

yg17

macrumors Pentium
Aug 1, 2004
15,027
3,002
St. Louis, MO
Which iPhone do you have?

The 3G and up have GPS. The original iPhone uses cell tower triangulation which is far less accurate.
 
R

randomerratum

macrumors 6502
Dec 3, 2009
289
0
Santa Monica, CA
The 3G, 3GS and iPhone 4 all have GPS...

Sometimes, the GPS takes a few minutes to acquire a satellite signal (and longer if you've recently traveled a long distance) so it'll use techniques such as triangulation between cell towers and referencing a database of known WiFi networks to gain a quick and dirty fix - this is mostly so apps like Yelp don't have to wait around for the GPS acquisition to find your city.

After about a minute or so, when it's got a good GPS lock, it's accurate down to a few yards... I use my iPhone to go Geocaching all the time and it's surprisingly precise when you give it a minute to catch up.

There are lots of apps that'll give you lat/long... but find one that also puts you on a map so you can verify with cross streets before you take it for it's word... again, try the Geocaching app out and you'll get an idea of how long it takes to zero in.
 
T

TruckdriverSean

macrumors 6502a
Feb 28, 2009
662
4
Texas, US
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_0 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8A293 Safari/6531.22.7)

Using the compass on an iPhone 4, I'm staring at the lat/long along the bottom of the UI.

Another roundabout method I used on my 3G was to locate myself on the "Maps" app and drop a pin. If you then chose "share" it would put your location (in decimal degrees) into an email link.

Also, so long as you have an iPhone 3G, 3GS or iPhone-4 you have a bonafide GPS chip in there. But acquiring a true GPS fix on my ole 3G did could take 15-45 seconds depending on where I was using it, weather, mood of device, etc. (would have to restart the 3G sometimes too) Until that GPS fix could be achieved, you were stuck with the A-GPS only, and depending on your area, could be WILDLY inaccurate.

My iPhone-4 gets a fix very quickly, but if I can't het a fix (indoors, tall buildings) then your still back to A-GPS instead.
 
V

vbmike73

macrumors regular
Original poster
Nov 8, 2008
149
3
Thank you to all who posted actual information. I truly appreciate it. I found one issue I have is that location services was for some reason turned off for the compass, so I wasn't seeing lat/lon at the bottom. And, maybe I'm just not giving it enough time to acquire the actual location by the GPS. Thanks again guys!
 
M

mmoto

macrumors member
Mar 21, 2009
51
0
vbmike73 said:
Thanks for that VERY HELPFUL answer!

My question was related to how much of a true GPS it is.
Click to expand...

Yes, the iPhone 4 does use satellites. If id did not it would not be called GPS. I've used my iPhone 4 GPS for route tracking while kayaking in some very remote areas. There certainly was no assistance from cellular or WiFi in those areas. The phone indicated No Service.

It's also worth noting that my iPhone 4 is much more accurate than my 3GS in poor GPS reception areas (under trees for example). It still can't beet my SiRF III chip-based GPS devices though.

-Brad
 
jclardy

jclardy

macrumors 601
Oct 6, 2008
4,159
4,365
vbmike73 said:
Thanks for that VERY HELPFUL answer!

My question was related to how much of a true GPS it is.

I'm not trying to be difficult here, but I really thought after typing up a detailed, LEGITIMATE question that I might get some useful replies. Instead I get the obvious pointed out to me, and a link to the Apple page where it actually has the words "Assisted GPS". That's great, seeing that I already stated it has Assisted GPS. If it were an actual Apple definition of A-GPS then that would be helpful.

MY GPS is showing me off by 3+ miles. So therefore, one can only assume that the final determination of my location is NOT by GPS. Why do you think there are so many issues with Find My iPhone and people saying it's not showing where they are? That shows me off by 3+ miles sometimes too. Something's going on here. It's not just my phone.
Click to expand...

Are you inside of a building or is it cloudy outside? Or near a bunch of skyscrapers? GPS works best when you have direct line of sight to the sky on a sunny day, iPhone or not (Unless you have military grade technology).

Sitting by the window in my room It can find me to within 10m or so after it gets an accurate lock (Which you have to wait at least 1-2 minutes for depending on when you last used GPS)

If you don't wait it will be inaccurate because it is going off of cell towers or wifi networks.
 
R

reliantj

macrumors 6502
Sep 8, 2008
283
0
i don't like the ip4 assisted gps. my real gps pinpoints me.

ip4's is usually off by a bit. and i saw proof of it after looking at the locations of my photos being taken. a bunch of my photos were taken at my house, but it pegs them being taken around my neighborhood.

eh, it's okay though. does the job usually.
 
M

mstrze

macrumors 68000
Nov 6, 2009
1,915
0
bripab007 said:
Is this a joke? How would a compass get your lat & lon?
Click to expand...

You apparently are not familiar with the Compass APP:
20090626compass1.jpg


Lat and Lon can be displayed at the bottom.
 
C

cwerdna

macrumors 6502a
Jan 19, 2005
555
203
SF Bay Area, California
yg17 said:
The original iPhone uses cell tower triangulation which is far less accurate.
Click to expand...
It also used cell towers in conjunction w/wi-fi hotspots and a database from Skyhook Wireless. This data is still used on iPhones after the 1st gen, even though they have real GPS. It's used to assist w/getting a faster lock and when you're inside a building that totally blocks GPS signals (e.g. many floors above you or lots of concrete and metal above you).

One can read more about how A-GPS and Skyhook all plays into this at http://www.skyhookwireless.com/howitworks/ (click on the links on the left too)

Also see http://www.usatoday.com/tech/products/2008-01-22-skyhook_N.htm and http://www.skyhookwireless.com/whoweare/news08.php, specifically references to iPhone.
 
Carnivor

Carnivor

macrumors regular
Feb 24, 2008
217
0
there is a free app called GPS Status,

by the guys over at pocketgpsworld.com it gives out some good info in fix strength etc.

funnily enough i tried death gripping it and my horizontal accuracy went from 10M (good fix) to 5m (excellent fix) i tried this several times on the trot, tight grip, loose grip, tight grip, loose grip etc, and every time it changed between the two.

So the "bad signal phenomena' does have a silver lining, grip it and you know where you are more accurately!
 
E

err404

macrumors 68030
Mar 4, 2007
2,525
623
A-GPS is superior to traditional GPS. It uses Cell tower triangulation to provide an immediate approximation of your location, even while indoors. Based off of this data it can very quickly lock onto the correct satellites to provide true GPS data.
Keep in mind that if the Assisted triangulation fails, it could take several minutes with an open view of the sky to acquire a lock.
 
T

TruckdriverSean

macrumors 6502a
Feb 28, 2009
662
4
Texas, US
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_0 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8A293 Safari/6531.22.7)

reliantj said:
i don't like the ip4 assisted gps. my real gps pinpoints me.

ip4's is usually off by a bit. and i saw proof of it after looking at the locations of my photos being taken. a bunch of my photos were taken at my house, but it pegs them being taken around my neighborhood.

eh, it's okay though. does the job usually.
Click to expand...

Lol!

I noticed this too on the geo-tagged photos when I first got my iPhone4 and opened up the "Places" folder.

I had loaded pics taken with my 'ole 3G and hadn't realized they were being geo-tagged. Looking at the map, I saw pics attached to places I didn't remember going. Upon investigation, it seems these were triangulation tagged pics. Most were either the first couple of pics from a longer string of pictures, or quick single pics taken indoors.

Photos taken later in the string (after the GPS got a good lock) were right where they should be so long as I wasn't buried in a building somewhere.

But I imagine a man or two may have had to explain GPS lock-on times to his SO over that one! :)
 
V

vbmike73

macrumors regular
Original poster
Nov 8, 2008
149
3
mstrze said:
You apparently are not familiar with the Compass APP:
20090626compass1.jpg


Lat and Lon can be displayed at the bottom.
Click to expand...

Just to clarify, based on the mistake I made, you must have location services enabled for the compass in order to see your lat/lon at the bottom.
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom