Enabling Wi-Fi to Improve Location Accuracy

Keith Gardner1 wrote:

So yes, there are reasons to have WiFi disabled. Now, it would be nice if someone would explain how the mere fact of WiFi being enabled could possibly help location accuracy. Still haven't found an answer to that one.

GPS uses satellites to determine location. It can take a couple of minutes to find a satellite if location services have been turned off or disrupted. Satellite signals can be interferred with by trees, tall buildings, topographic features. Cell phones compensate for some of these shortcomings by using both cellular and WiFi to assist in pinpointing a location (that's why it's called Assisted GPS).

See here for some further information:

http://en.wikipedia.org/wiki/Assisted_GPS

Clearly there are lots of people drinking the kool-aid that just run around wasting prescious battery power with their wifi on. I dont care if wifi improved my accuracy or not. I just dont want the **** notifications anymore.

Um, enable WiFi? It doesn't use much power.

If that seems just too crazy, remove the apps you're having trouble with from location services. Settings>Privacy>Location Services and set those apps to "Off".

Pat answers don't always answer the questions suitably.

In this case, while I don't get the repetitive prompts friedduck is getting, I can give my reasons for not keeping WiFi enabled. NYC has this new-ish thing in the subways, WiFi provided by Boingo hotspots. Each time I'm in the subway and I think I'm going to dash off a quick email to someone or get that answer from Wikipedia, if my WiFi is enabled I'm instead going to be intercepted by a login screen, an ad, or a simple "unable to connect" because I haven't re-authenticated myself. It is far preferable to use 3G when I'm underground and catch a signal when I can, because I don't have to jump through hoops to get connected. Consequently, I'm constantly in and out of my WiFi network settings, which is a real annoyance.

Also, when leaving my office or apartment and on the elevator or otherwise leaving the vicinity of the hotspot, it seems that my iPhone relentlessly wants to hold on to that WiFi signal, even though it's got one bar and teetering on the brink of extinction, where clearly I'd have the response already if it had switched to 3G. So I manually switch to 3G in these situations from time to time.

So yes, there are reasons to have WiFi disabled. Now, it would be nice if someone would explain how the mere fact of WiFi being enabled could possibly help location accuracy. Still haven't found an answer to that one.

It has to do with the fact the iPhone does not use pure GPS for location. It uses what is called Assistive GPS, which uses cell tower triangulation and wi-fi location information to help locate the device. It is faster than straight GPS, when most of the time, the device is not located out in the open to be able to "see" the GPS satellites.

Hello,

I looked through that wikipedia article and I could not find in it where Assisted-GPS uses Wi-Fi for location information. I did see a mention of WPS (Wi-Fi Positioning System). But WPS is a different beast from regular Wi-Fi.

How many Wi-Fi routers provide Wi-Fi Positioning System data to the clients?

I have yet to find a Wi-Fi router that I can buy that includes a GPS receiver.

By the way, I also have many similar scenarios for why I want to leave my Wi-Fi radio turned off.

Plus, it does not make any mention to "connecting" to a Wi-Fi router. So, merely having the Wi-Fi radio turned on and NOT being connected to any Wi-Fi routers assists with location accuracy? Because it seems that turning the Wi-Fi radio on and NOT being connected to any Wi-Fi routers/servers, stops the nagging dialog box from popping up all the time. This seems strange to me because it seems that it should stop nagging only AFTER one has connected to a Wi-Fi router, no? I mean, it couldn't possible want me to just leave my Wi-Fi radio turned on all the time, regardless of whether or not I was actually connected to a router/server, now would it?

Skyhook, assuming that it delivers all that it promises, is deployed where and in what quantity? Maybe .1% of the Wi-Fi routers out there?

I could imagine how quickly it would be if done this way. I can also imagine many other not so cool things about how this is done.

The last point is taken. I am in a field with no Wi-Fi around me for miles. I have launched google maps and my position is shown as a large circle. I now turn on my Wi-Fi radio and my position will be pinpointed pretty quickly -- based on what?

Thank you for your time and consideration. 🙂

Much more than 1% with most people not knowing this gathered by Google while doing street view mapping.

http://gps.about.com/od/glossary/g/wifi_position.htm

Thank you for your reply.

If it is much more than .1%, then what is the number? Closer to what percentage?

I read the story that was shared. I must confess that it sounds like a lot of b.s.

"It is now widely acknowledged, however, that Google, Apple, and various phone makers and carriers have compiled their very own extensive databases of wi-fi access points locations [...]"

So far so good, but the rest of the sentence is murky.

"by correlating Wi-Fi access points with GPS locations of cell phone, smartphone, and in some cases, tablet computer users." hmm ... what? What does this mean exactly???

Let us pretend that this is legitimate and ask "How does this correlated data actually get sent to my iPhone? How does this correlated data help A-GPS? Remember, I am not connected to any Wi-Fi routers, only my Wi-Fi is turned on. The "correlated data" is pushed to my iPhone over my carrier's data connection? This would mean that the carrier knows all of the Wi-Fi access points that I have ever walked past and NEVER actually connected to. Yes? And that this is the reason that I am told that I should leave my Wi-Fi radio turned on? If I leave it turned on, then my location will be tracked and then this (my) location data will be correlated with any and all Wi-Fi routers that I come into proximity with, despite not connecting to it, nor even being authorized to connect to it?

Lastly, how is this correlated data -- well, correlated? Just how does the science work that provides the GPS coordinates of the Wi-Fi routers that are being mapped/tracked? War-driving? Definitely not. So?

Thank you again for your time and consideration. I appreciate the responses.

gravityron wrote:

I looked through that wikipedia article and I could not find in it where Assisted-GPS uses Wi-Fi for location information. I did see a mention of WPS (Wi-Fi Positioning System). But WPS is a different beast from regular Wi-Fi.

Then I guess you missed this part;

"Many mobile phones combine A-GPS and other location services including Wi-Fi Positioning System and cell-site multilateration and sometimes a hybrid positioning system.^[4]"

Hello Meg,

Thank you for your reply. No, I did not miss that part. 🙂 It was irrelavent, as a distraction, because it does not answer/solve the question/problem.

Namaste 🙂

TURN GPS ON. If you don't want it to connect to random hotspots turn off "Ask to join networks" and Forget any it has connected to.