iPhone 5 and Satellite GPS

The spec page will show that each model since iphone 3g has a GPS reciever.

You can see the iphone 4 and 4s spec currently:

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"They never have. The GPS system on all past and current iphones have all been celluar and wifi based. "

This is NOT true. Why do you think this? All iphones since iphone 3g have indeed had true gps.

You are completely wrong about this.

Why do you think this?

All iphones since iphone 3g have indeed had true gps.

I have used my GPS without wi-fi or cell service many times.

You can look this up for yourself.

Why do you think that it does not have true GPS?

Assited GOS only mean that it will use the cell tower or wi-fi router to get a faster fix. All iphones since iphone 3g have a true gps reciever.

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.

By "disabled the radio", do you mean put it into airplane mode, which disables the GPS.

http://support.apple.com/kb/HT1355?viewlocale=en_US&locale=en_US

Some info on the iPhone 4 and 4S:

GPS

The iPhone 4 previously used a BCM4750 single chip GPS receiver, and shared the 2.4 GHz WiFi antenna as shown many times in diagrams. We reported with the CDMA iPhone 4 that Qualcomm’s GPS inside MDM6600 was being used in place of some discrete solution, and showed a video demonstrating its improved GPS fix. I suspected at the time that the CDMA iPhone 4 might be using GLONASS from MDM6600 (in fact, the MDM6600 amss actually flashed onto the CDMA iPhone 4 includes many GLONASS references), but never was able to concretely confirm it was actually being used.

MDM6610 inside the 4S inherits the same Qualcomm GNSS (Global Navigation Satellite System) Gen8 support, namely GPS and its Russian equivalent, GLONASS. The two can be used in conjunction at the same time and deliver a more reliable 3D fix onboad MDM6610, which is what the 4S does indeed appear to be using. GPS and GLONASS are functionally very similar, and combined support for GPS and GLONASS at the same time is something most modern receivers do now. There are even receivers which support the EU’s standard, Galileo, though it isn’t completed yet. This time around, Apple is being direct about its inclusion of GLONASS. The GPS inside MDM6610 fully supports standalone mode, and assisted mode from UMTS, GSM, OMA, and gpsOneXTRA.

http://www.anandtech.com/show/4971/apple-iphone-4s-review-att-verizon/9

Your last paragraph is correct. Airplane mode turns off the GPS receiver. It's required by the FAA. You can also verfy that the iPhone 5 has a GPS receiver by looking at the official hardware stats:

http://www.apple.com/iphone/specs.html

You are also correct that the iPhone uses the cell site and/or WiFi location data for positioning. The CoreLocation API allows app developers to get the current device location. CoreLocation uses the available data from the 3 radios and determines the position to an accuracy specified by the developer.

http://developer.apple.com/library/ios/#documentation/CoreLocation/Reference/Cor eLocation_Framework/_index.html

Finally, you can verify that the iPhone has a GPS by driving down most any road. Cell tower triangulation is accurate to maybe a few city blocks, depending on the cell density. WiFi triangulation only helps when there are WiFi signals nearby. Download an app like MotionX GPS and start recording your route. You will notice that your route matches the road you're driving on almost exactly, with position information every few meters. If it was only using cell tower triangulation, it would be jumping all over the map. If it was only using WiFi, you would jump from one WiFi location to another, with no updates when no WiFi signals were available. Even the combination of cell tower and WiFi would produce a scatter-plot of positions, rather than a linear, equally spaced set of positions that line up with the road you're on.

The WiFi location feature is especially effective for iOS devices without GPS when you are staying in one spot or walking down a sidewalk in a downtown area where there are many wifi signals. Even then, it is only accurate to a few hundred feet. GPS (without WAAS) is accurate to about 10 meters in good conditions.

So this is a conversation between myself and an Apple Care support rep. Please let me know where I am wrong in my thinking. I am totally confused now.

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It looks like you are having issues with your GPS not working right for you, is that correct?

ME: yes. My gps will no longer work. When connected to wifi or phone signal it seems to operate ok, but when none are available the gps is no longer able to function.

ME; i would like to make sure it is not working before I decide what to do

So sorry you are having this issue. I’ve ran into something similar before as well so I certainly understand what you’re going through. No worries though, you’re in great hands now and I’m sure we’ll figure this out together. I may need to ask some questions throughout our chat to help me understand how you are using , isolate the issue or come up with a resolution for you, will that be OK with you?

ME; great. Yeah I use the gps a lot.

I understand that! I do the something myself. If I don’t know where to go or I’ve never been there before, I GPS it. I also use it a lot for my backing weekends as well.

ME; same here

Where are you currently located at Brent as far as city and state?

ME; Sabinal, Tx

Awesome!

I’d like to have been down there all winter. It had to of been warmer than here.

ME; lol. yeah. It was 88 this weekend

Nice! So to make sure I understand you correctly, when you don’t have a cellular signal or Wi FI signal, your GPS doesn’t work. Does the sound right?

ME; when I dont have a phone signal, the iphone maps app will say "location cannot be determined".

ME; yes. that is correct

ME; i have re-booted, hard re-booted, calibrated compass, etc. I cant get it to come back and work

Sure thing! That actually sounds like it is working how it’s supposed to. Since there isn’t a signal of some sort coming or going from the phone, it has no way to find itself. It needs to have one of those connections in order to find itself in the world.

ME; it has worked in the past without a phone signal. I thought the iphone has a gps receiver

ME; i understand that the iphone will use cell towers to pinpoint its location faster, but can use gps alone to locate, etc

I wish it did but without a signal, it has no way to see what’s around you.

ME:i had my brother's iphone out next to it, and his was able to tract and locate our position without a problem, while mine was not

It must have been connected to a WI FI connection or a cellular connection. It has to have one of the two in order to work.

ME: ok. so you are saying that iphone does not have a gps receiver chip inside of it?

ME: i dont understand, because in the past I have used my gps without any type of singal whatsoever

I’m saying it has to have a connection in order for it to work. It has GPS abilities but it has to have a signal for it to work.

ME: are you talking about gps signal, or tower signals?

That is technically impossible. Even third party GPS units still have a satellite connection.

ME: or example, it will say "no service" and my gps will still work.

Let me see if I can find you some information on it. That way, you can see what I’m talking about.

ME: ok. I am speaking of phone signals. Not gps sattelite signals

ME: this weekend, my brother and I were 20 miles from the nearest wifi signal. both of us had "no service" and could not make calls. His iphone was able to determine our location with the gps app. MIne was not. How is that possible?

It sounds like he had cellular data on his phone.

ME: so from what you are saying, my iphone's gps will not work unless I have a bar of signal?

Correct! It has to have some type of connection to the world. Every GPS unit, in every mobile device, has to have some type of connection.

ME: well i also have an older iphone 3G that doesnt not even have a sim card inside of it and I use the gps app . So even without the sim card it still works?

ME: ok. well what would you suggest I do? So youre saying the iphone is working fine?

ME: this is from apple's support forums. 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.

It sounds like it Brent. Her is an article about it that might explain it better. https://discussions.apple.com/thread/3157214

ME: is that article wrong?

Let me get you in touch with a senior advisor. That way, you can get the most accurate information.

ME: ok. thanks

Getting them pulled up now for you Brent. One minute.

Is it OK if I let you speak with Matthew now?

sure. \

Great! Wish you the best and here is Matthew

You are now being connected to another Advisor. Please standby.

Now Chatting with Matthew

Thanks for contacting AppleCare chat support. My name is Matthew. Please give me a moment to look over your information.

Hello Brent. I understand that you are having some concerns about your iPhone and using Maps in conjunction with it.

I can see how that is a concern. I know I use Maps to get to a lot of unfamiliar places myself.

ME: the trouble I am having involves the iphone using its offlline gps. In the past, my iphone has worked without any cell tower service (no bars of service or wifi connected). The locations I have used it are 20 miles from the nearest wifi. It has no service whatsoever. However, this hasnt been a problem in the past. I have opened my gps app and was able to determine my location and track me. Now, it will not do that unless I have service (bars).

ME: my old 3GS iphone which does not have a sim card can still track me where there is no service, while my iphone4S cannot. There is something wrong with it. Like I stated earlier, I have been told my multiple other support people that Iphones have a GPS receiver in it, which can determine your location without the need of phone service. Today I have been told something completely different and that my past experiences have shown.

Okay. I do see how that is a difference.

The GPS is a software based feature and is not designed to work without a signal now.

ME: now? Has it changed?

It was not like that before, however if you say that it works, I am not going to say otherewise.

Even on our earlier models it should require a signal.

ME: when you say "signal", do you mean bars?

It may have used cell tower pinging to get an approximate location, but it would have not been true GPS

I mean a connection of some sort.

ME: well, this weekend my brother and I were camping. Neither of us had any "bars of service". His exact same model of iphone was able to quickly determine our location and track us. My iphone4S kept saying "cannot determine location".

ME: we both use the same carrier, etc

Okay. Well you can restore the device back to factory settings. Erasing all the information and putting on a new operating system to see if something with the OS is not allowing your phone to behave as your brothers, however in my opinion it is expected behavior.

ME: another example is that I was at a location where it was not able to determine my location. Two weeks ago my gps was able to pinpoint my location at that sepcific spot. Why has it been able to before, but not now?

ok. I will try restoring it.

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END OF CONVO

@roaminggome

They never have. The GPS system on all past and current iphones have all been celluar and wifi based. The OP was asking if the new IPhone 5 has a real true built in GPS receiver like the ones used on TOM TOMs, Garmin, and magelian. None of which require a subscriotion, use of a costly data plan, or need to be near a wifi hot spot.

And to answer his question. I don't know but god....I really hope it does have a built in SAT based gps.

I hike as well and have no issue with getting a GPS fix outside of cell range and wi-fi. It does need a clear view of the sky.

I use preloaded maps while hiking and mountain biking regularly.

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

Hey you know what. I was totaly wrong. My bad. I was thinking about the google map app which does not have any preloaded maps. That's why you needed to a data signal to download them. There are other apps you can download which come with maps pre-downloaded so you don't need a cellular/wifi connection. Thanks for fact checking me on this 🙂