Locate me varies from iPhone to iPhone

Question

Level 1

4 points

Locate me varies from iPhone to iPhone

In my office we have 3 iphones. Side by side by side on a desk they produce wildly varying results when Google Maps uses cell tower triangulation. All settings are the same and wi-fi is off. Each one of them has the exact same case and screen protector. The only difference I can think of is that #2 and #3 were bought on release day and #1 is was bought during the holidays.

iPhone #1 zeros right in on the exact location of the office with a circle that is maybe half a block wide. iPhone #2 and #3 both show a circle that is roughly 2 miles in diameter, the center of which is off by a good 1/4 mile. I tried powering off all three phones and letting Google maps have multiple chances to to reload the location and its always the same: iPhone #1 is super accurate and the other 2 are so vague as to be almost useless.

What gives?

20" iMac G5 iSight 2.1 (2.1 GHz), Mac OS X (10.4.3), 1.5 GB RAM 250GB HD

Posted on Jan 18, 2008 11:34 AM

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Answer 1

DaVBMan

Level 6

9,280 points

Jan 18, 2008 11:48 AM in response to ggarness

ggarness wrote:
Side by side by side on a desk

This in itself can cause it. Interference (from a variety of sources) skews the data needed. There are reports where one is in his home and it is close, but if he stands by his TV it is off by miles (circle not even around his neighborhood). Move away from TV, and close again.

Please remember (there have been many posts here complaining). It is not meant to be perfect. It is more abut getting near you (and miles is still near) for when you want to find things near you. eg. Click locate me. If off by mile or so that is fine the zoom level will still be your local area. Then search for what you want. It will show what is in your area. That is the main purpose of it. Not to be perfect and find your exact spot. Then the trip is once it gets close to you, do a Drop Pin and put it where you know you are. Then you can click that drop pin and get directions form that Point. The locate is there to just help you zoom into where you are.

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Answer 2

Jan 18, 2008 12:10 PM in response to ggarness

A much better test would be to put them all in the same spot individually and test them.

I am quite sure your results will still vary quite a bit.

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Answer 3

ggarness Author

Level 1

4 points

Jan 18, 2008 2:35 PM in response to th3_r3n3g4d3

Tried that. And actually it doesn't vary much at all. One phone always gets tight, accurate results. The other two always get vague 2 mile circles or proximity.

I wonder if the newly manufactured iPhones have more sensitive antennas? Its very weird.

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Answer 4

Jan 18, 2008 2:58 PM in response to ggarness

Interesting to say the least.

Everyone I know(6 total iPhones) get different results constantly.

Myself I can test in the exact same spot and get different results every time. The distance it is off is pretty consistent, but the location always changes. Go figure!

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Answer 5

allamb

Level 1

10 points

Jan 18, 2008 3:36 PM in response to ggarness

Try the test with wi-fi on. The accuracy seems much better...

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Answer 6

Ansuz82

Level 6

8,285 points

Jan 18, 2008 3:38 PM in response to allamb

Thats due to the fact that Google Maps on the iPhone also uses WiFi positioning for known hotspots.

If your hot spot has been mapped you be pinged within about 20 feet. If it hasn't it won't help a lick.

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Answer 7

Jan 18, 2008 4:52 PM in response to ggarness

in a way i like this function but at the office which is on a military installation it's so out of place. even in the city, at main roads it's not really accure.

its still helpfull in a big city where 100's of spots actl. help this function to ID ur currectn spot.

i think that this is just the first step into GPS Live function, with Life Tracking. so the next update at Apple and AT&T will fix this better.

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Answer 8

MobileDev

Level 3

565 points

Jan 19, 2008 8:30 AM in response to ggarness

In my office we have 3 iphones. Side by side by side on a desk they produce wildly varying results when Google Maps uses cell tower triangulation.

Just bear in mind that it's not doing actual "tower triangulation".

It's using the id and estimated area of the cell that it's currently linked to.

So one phone could be using a very small, local cell, and the others (because of congestion or signal strength) might be using a cell further away.

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