iPhone 5 and Satellite GPS

this myth is old

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

it mean it use the gsm to get a quick pos fix with poor acuacy but it don't mean it don't use the satelites

it works without sim cards and use no data

and is not! the 3 gsm tower poor pos fix the first iphone had

There are apps that might suit your requirements. They include off-line maps. I do not have any of them but one I have looked at in the iTunes store is GPS Kit.

As rominggnome showed, the iPhone does have a GPS receiver, and has since the iPhone 3G. And as Rudegar pointed out, the iPhone also has A-GPS capability, which lets the GPS receiver determine its current location much faster than normal. Without A-GPS, the GPS receiver has to wait -- sometimes multiple minutes -- before it can determine its location, because it doesn't know where the satellites are. A-GPS allows the phone to download satellite almanac data over the cellular network, so the GPS receiver can immediately know where all the satellites are. A-GPS is not necessary, however, for GPS operation -- even if you have no cellular service, you can still use the GPS receiver in the iPhone. I have done this many times, so I have no idea why your friends have had trouble. I recommend the MotionX GPS app, and it works really well out in the woods. You can even download offline map data.

But what the iPhone does NOT have is WAAS capability. The GPS receiver works by measuring how long it takes for the radio signals to propagate between the satellites and the receiver. The propagation time varies based on the current density of the atmosphere between each satellite and the receiver. Because of the density flucuations, a standard GPS receiver can only get a fix that is accurate to about 10 meters. However, some geostationary satellites transmit atmospheric density information that lets GPS receivers compensate for current atmospheric conditions, and this enables accuracies in the neighborhood of about 1 meter. Garmin has had WAAS capable receivers for years, as have other hand-held and aviation-based GPS receivers, so it is a bit surprising that Apple has not incorporated WAAS into their GPS radio -- especially since WAAS density data can be downloaded via the Internet, eliminating the need for increased radio weight. I and others have submitted requests for a WAAS capable GPS receiver in the iPhone, but Apple has not delivered. Perhaps it is because WAAS is only available in North America. However, according to the specs for the iPhone 4S and 5, it now supports GLONASS, which provides near-WAAS accuracy when combined with standard GPS, and is available worldwide. At least that is the next best thing to WAAS.

Now, the CoreLocation service on the iPhone combines 3 completely separate technologies: GPS, cell tower triangulation, and Wifi-based location. I don't know the algorithm they use, but I presume that they use whatever service is currently providing the most accurate location information.

Note that cell tower triangulation has nothing to do with GPS.

You are wrong that GPS has nothing to do with cell triangulation. A-GPS is still GPS and it uses cell towers

Very good discussion. I think the issue has a lot to do with Airplane mode. I have used the iphone GPS many times on commercial aircraft but it does not work in Airplane mode because that disables the GPS receiver. If I don't turn on Airplane mode (don't tell TSA) and if I have a fix before taking off, I can usually get it to track, even up to cruising altitude (there are some cool apps that give your altitude, speed, rate of climb, etc.), although I often loose the fix at some point. I think the cellular connection "assists" in the initial fix and then the GPS continues to keep the fix but if it looses it, the fix is hard to get back. Of course this runs down the battery becasue the phone is always looking for that cell signal. Maybe the sim lock code that someone mentioned is worth a try so you can turn off cellular without turning off GPS.

Okay, I tried a few things to get GPS to work on it's own.

I turned on the sim card lock pin: Settings--phone--SIM pin--ON

This means that when the phone is turned back on after being powered completely off (Hold down button top for about 5 seconds), you have to enter the SIM pin code when you power it back up.

Powered off the phone

Powered it back on

Did NOT enter the SIM pin

Turned off Cellular data: Settings--General--Cellular--OFF

I turned off Wifi also

Turned on a variety of maps and they worked just fine showing my current location and tracking when my location changed.

The step that is kind of strange is that you have to power OFF and then back ON to initiate the SIM card lock. I'll try it next time I fly.

I use the TomTom app which contains map data for the entire U.S. and does not need to be connected to a network of any type to run just fine. Since I deactivated my 3GS (no cell data at all) and relegated it to mostly iPod use, I have also continued to use it for navigation in one of our cars. Once oriented it works just as good as before, even out in the middle of nowhere. It continues to work better than the car's own overpriced OEM nav system.

Because it lacks the supplementary A-GPS functionality it can take a little longer to orient itself at first if I am not around wireless networks, but this is trivial. i do not understand the obstinance of those who cling to the notion that this device does not have a true GPS receiver. It clearly does, and it works very well.

I just tried the iPhone 5 out at 40,000' (offline). It is able to find its current position extremely quickly. Going from Airplane mode on to off it rarely took more than 30 seconds to find its current position. Even after shutting the phone off and waiting 200 miles it took less then a couple of minutes to locate itself. Combine this with the new Apple (TomTom) vector maps that are still available offline and this is one amazing device!

I don't think Apple Vector map can download city map seperately. Motionx has turn by turn, but it needs monthly fee for keep using it. I can't find a GPS app in reasonable price and no monthly fee. When I came to china, I can use an app called Autonavi Navigation, it's totally free and even has two choice 'drive' and 'walk & bus'.

So just wandering if you know or anyone else knows then does the apple iPhone 5 have a GPS and does that use your data plan

Well PT, read the above extensive thread for your answer to question #1. For #2, yes it uses cellular data unless you have a map that resides "physically" on your iphone. I have Tomtom USA maps that take up about 1 GB of storage but there are other maps you can download that will work with the GPS.

Thanks that's answered my questions :):):):)

I just spent a week in the Grand Canyon with, of course, no cell service. I was able to track my location on a Pre-downloaded map for the duration of my trip. If I turned airplane mode on, my tracking would disappear. For the GPS to work you need airplane mode off.