Currently Being ModeratedSep 13, 2012 7:54 AM (in response to roaminggnome)
Where did you get the idea that it does not have this feature?
Here is my theory:
On occassion the Maps app will show my "location" with a static black dot instead of a blue one that moves with me. I assume this happens when it doesn't have a lock on my position. On my 3G with no sim card there is no cell tower triangulation to fill in when a GPS solution has not been established. Being out of cell tower range would be a similar situation. That might lead someone to think the GPS requires the cell towers, which it does not.
Currently Being ModeratedSep 13, 2012 8:16 AM (in response to roaminggnome)
@ BadUnit: Thanks for the information, I was not aware that the iPhone was using a Qualcomm chip. Also thank you for the links.
@roaminggnome: It's not that I do not believe it. I am just going based on experience with friends and hikers that I take into the white's that have iPhones that are not able to track their progress. I have always wanted to move into an iPhone, but I always enjoyed having the android with the Backcountry Navigator Pro app to track my progress and the ability to download any topo, street and marine maps onto that unit for any trip that I was taking.
However, based on what everyone is saying, and as long as the new iPhone has the same processor and capabilaties, then it would seem that the iPhone can inded track wihtout cell/wifi connectivity, which is the main reason i started this conversation. I will be looking at the links from BadUnit and if that is the case, then it's very possible that Apple may get my hard earned dollars....
Currently Being ModeratedSep 13, 2012 8:25 AM (in response to JohnPacheco)
this myth is old
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
Currently Being ModeratedSep 13, 2012 9:10 PM (in response to JohnPacheco)
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.
Currently Being ModeratedSep 26, 2012 7:57 AM (in response to MeplatMasher)
I am taking a trip this weekend and have asked my daughter, after it seems like I was asking her to remove one of her limbs, to borrow her iPhone. I will be testing some of the APPS recommended. Again i thank everyone that has posted to this, and welcome any new information that others may have.
to MeplatMasherthanks for the information.
Currently Being ModeratedOct 4, 2012 2:42 PM (in response to JohnPacheco)
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.
Currently Being ModeratedOct 5, 2012 9:18 AM (in response to JohnPacheco)
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.
Currently Being ModeratedOct 6, 2012 7:55 PM (in response to hadtomakeupaname)
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.
Currently Being ModeratedOct 11, 2012 11:20 PM (in response to Gary K.)
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!
Currently Being ModeratedJan 16, 2013 7:37 PM (in response to SkyWriterSoft)
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'.
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.