I know that it's mostly "approximate".
But, I must know the EXACT location of the phone, regardless of battery life or whatever. I need the exact location of the phone! Is it possible?
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389answers:
5
+1
A:
Define 'exact' and then we'll tell you. If it doesn't move and you've got a month, then better than a millimeter is probably possible (they track earthquake faults this way). But if it's moving, or doesn't have a good view of the sky, then it's not going to work nearly so well. And the math to do long-term averaging is pretty heavy going.
Andrew McGregor
2010-01-23 11:32:44
Umm...how about...walking speed?
TIMEX
2010-01-23 11:34:27
So, it's going to be within about 17m, as another answer says, presuming you have GPS reception, and otherwise it will vary; if an iPhone has a data connection, and Google have mapped some WiFi APs nearby, it'll be within about 50m. If it has to go on cell towers, it'll probably be in the right town.
Andrew McGregor
2010-01-23 12:31:48
+8
A:
It depends on what you mean by exact!
Any location technology will have a level of accuracy and much of this depends on the hardware your using. Mil spec GPS will cost a lot more than the chipset in your iPhone and use a lot more power too.
The best I've managed to get using the browser with iPhone 3GS GPS in wide open space is +/-17m
Usually its best to design you application around this for example most turn by turn sat-nav assumes you must be on a road and correct the location for this.
Sam Machin
2010-01-23 11:34:15
Sam has the correct answer. If you were expecting accuracy down to the centimeter then you're going to be disappointed. You might want to read up on how GPS technology works: http://en.wikipedia.org/wiki/Global_Positioning_System
mbaird
2010-01-23 15:58:37
A:
Look into fine GPS location in the location API's(on Android)...that's the most "exact" you're gonna get. If you get a good GPS lock it'll probably be <10 meters. I just tested while in my house and got <5 meters.
Aakash Patel
2010-01-24 05:29:36
+1
A:
From the point of view of fundamental physics this question is meaningless. No physical measurement can ever be EXACT. There is ALWAYS a tolerance. Even if you went back to your national datum point and surveyed your position back to the point in question there will be errors in the measurements taken that will result in a non exact position.
If you then put your device on the ground - where on the device are you measuring to - the top left corner, the intersection of the diagonals across the device, the antenna position...?
"Regardless of battery life" - are you implying that the position measurement must occur in the absence of power?
Ian
2010-01-27 09:09:54