GPS with no cell service

Here's my experience on this topic. I was recently at a remote beach in SW Western Australia, with absolutely NO cell service.
However, i wanted to drop a pin in maps to pinpoint my location for when I wanted to go back.
If you open maps with no cell service, you WILL get just a blank screen - HOWEVER, GPS still works FINE, and allows you to drop a pin with no problems. When I got back to an area with cell service, there was the pin, in the correct location, now with the correct map.
So while it's not very useful when out of cell range, the GPS chip does know where you are, and you can mark your location for later reference.

The iPhone is not a pure GPS device. It uses A-GPS, or assisted GPS. It requires a cell signal to approximate your location and then uses the GPS chip to pinpoint.

Most phone GPS systems work this way.

Ah, in a word, NO that's not right.

It uses cell towers when it can't see the sky. (can't see the satellites).
With a clear view of the sky it knows exact longitude and latitude coordinates (usually to within 100 feet or so).

The reason the OP couldn't find their location is because it draws maps from
web sources. No maps, no display.

If geotagging was turned on, taking a picture would still yield a geotagged image.

Unfortunately, I'm not not aware of any way to get the numerical Long/Lat figures out of the phone. Maybe something like Snail Trail ( http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=288352724&mt=8 )
or Breadcrumbs ( http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=286545866&mt=8 ) or
gps Compass ( http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=286550480&mt=8 )
from the App store would be useful in remote locations.

{quote:title=evdh wrote:}When I put it in AirPlane mode there is no information available, not in googleMaps, not in other apps like GPS Kit. Just test it for yourself if you have an iPhone. It can be that when in AirPlane mode the GPS unit is also turned off. I don't know that.{quote}

Now I know...

When airplane mode is on, no cell phone, radio, or Bluetooth signals are emitted from iPhone (and GPS is not available with iPhone 3G).

I found this in the following artical : http://support.apple.com/kb/HT1355

You can get latitude and longitude readings without getting the map from internet with some applications, such as:
<http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=286022285&mt= 8>
If you carry a paper map, that will show you your location. It will also display the distance and direction to a starting location.

You need a cell service. And you need one that is working together with your iPhone. If you put your iPhone in AirPlane mode, there will but no GPS info. For the moment I use the app GPS Kit (great one) and it only works when there is a cell service available. In Blegium I have no problem using it. But last month I was in Germany and Italy and there you can use all the cell services available. All of them work well if you use it for making a phonecall, but if you want to use the GPS function, you have to choose the cell service that is supported. In Italy the GPS unit was not working with 'I WIND', but it was working with 'I TIM'. In Germany I had the same problem. It was working with 'E-Plus'. Here in Blegium it works with all the cell services (BASE, Mobistar and Proximus)

evdh wrote:
You need a cell service. And you need one that is working together with your iPhone.

No. Not true. Read some of the posts above. You don't know what you are talking about. It does not need cell service.

NO, as already mentioned iPhone uses assisted GPS, that is it has no satellite receiver and it gets this information from the cell towers to feed its GPS chip.

Yes, independent GPS units will use satellites directly and will work where no cell tower signal is being received by the iPhone. Conversely iPhone's GPS will work underground and in buildings where satellite signals cannot penetrate.

PGORDINI wrote: Am I doing something wrong or is there a workaround/solution to this?

A small word about iPhone and Google's GPS coordinates.

iPhone uses Google Maps, these are based on the pixel, this means they radiate outwards from the center, maps are read from the top left hand corner and as such are only accurate for devices using Google maps.

Use ordinance survey maps and use you iPhone's co-ordinate's and one will be about fifteen miles off target in a map block covering about ten square miles.

In other words, if the AIS and Radar breaks down in your cruise ship at sea, iPhone WILL put it on the rocks in reality. If you're a platoon commander and call in a fire mission from your iPhone, you'll miss by miles ~ unless, unless the fire base is ALSO using an iPhone ~~ 😉

I'm reading many information here. For me it's very clear...
The iPhone has a real GPS unit build into the device. It's working fine when you don't put the iPhone in AirPlane mode. When I put it in AirPlane mode there is no information available, not in googleMaps, not in other apps like GPS Kit. Just test it for yourself if you have an iPhone. It can be that when in AirPlane mode the GPS unit is also turned off. I don't know that.
If there is a cell receiver available it's working fine. In GoogleMaps you first get a blue circle (coordinates coming from the cell receiver) and then there comes a blue disc which will finetune your location and it is using the GPS information.
But when I was in Italy I had to choose the cell receiver that was working together with the iPhone. When I selected 'I WIND' it was NOT working. I waited for 5 minutes. When I selected 'I TIM' I get the exact spot after less than 1 Minute.
So if you can, take your iPhone and test it for yourself.

Perhaps it's working fine when there is no cell receiver available (I didn't test this one) but in Italy and Germany I had to select the cell receiver that was working together with the iPhone. When I selected 'I WIND' I had NO GPS information available.

It must have cell phone data to work.

It can give you it's version of co-ordinates without a cell tower, and if you know the offsets to apply, you can apply them to an ordinance survey map with a compass and calculator.

But it won't plot a solution home or the other stuff it can do, a Garmin GPS will guide you in the direction of there you want to go, even if off the map ~~ try it for yourself with the iPhone, off the map and with no service.

icebike wrote:
It has a real gps and will work where there is no cell service.

Any statement to the contrary is just wrong!

AND an error message like cannot locate current position!

For the most part, iPhone tends to be more accurate when working, Garmin like GPS systems are often wrong as they also use 'predictive' logic and may place one on nearby roadways when one is in a field or unmarked shopping centre.

icebike wrote: No maps, no display..

GPS worked fine for me with no cell coverage. I just dropped pins on boundary lines and other points as we walked through the woods and used the pins later to see where we were via aerial. Pretty handy.

You, Mr Bons, have posted three times in this thread and every single one of them have been dead wrong and/or totally nonsense.

Assisted GPS does NOT mean that it has no GPS receiver. It most certainly DOES have a GPS receiver.

It uses the Infinion PMB252 Hammerhead Gps receiver: http://i.cmpnet.com/techonline/uth/pmiPhone_boardtopBIG.jpg

See article: http://www.techonline.com/product/underthehood/209000013?pgno=1

That chip is described here: http://www.infineon.com/cms/en/corporate/press/news/releases/2004/132119.html

The Assisted feature of this chip allows Three things:
1) Best Guess location (based on tower location data) when inside buildings, where satellite signals do not penetrate.
2) Faster Satellite lock when outside, reducing lock time from several minutes to seconds.
3) Ability to use vastly weaker GPS signals when inside a building allowing for precise locations even in challenging environments.

In the absence of cellular tower data, satellite acquisition is slower, but with a clear view of the sky it will be quite accurate within 3 minutes.

*Now PLEASE STOP posting nonsense and Slander about APPLE products and do JUST A LITTLE research.*