Satellite or Cell Signal?

[airpix]

Does anyone know if the Google map program on the iphone4 uses satellite or cell tower signals to find its location? Is there GPS built into the phone?

Thanks, Airpix

 

[iGaz]

GPS is built into the iPhone but I believe it uses your network signal somehow.

Some say they can get GPS to work without a signal but for me poor/no signal = poor/no GPS...

 

[EWyatt]

Airpix.... good question. I believe I read that the iPhone actually uses the GPS satellites for GPS, but I don't know for sure. It would be easy to test: just turn off your 3G, cellular data, and wi-fi, and see if you can get a current location in the iPhone's "Maps" app. Let us know....

 

[geoff5093]

It uses both. I believe it uses the network location at first, which is why when you first open Google Maps the location is a bit off with a large radius, then since the phone already knows where it is it can acquire a much faster GPS lock using satellites, which gives you an accurate location.

 

[Dave12308]

It's called a-GPS (assisted GPS). It uses the network location in conjunction with the satellites, supposedly makes it more accurate than using the satellites alone.

The reason a 3G/WiFi connection is needed to show your location in maps has nothing to do with a-GPS though. It's simply because the map data streams over the data connection. The maps are not stored locally.

 

[geoff5093]

The iPhone's version of Google Maps can't cache map tiles for offline use? That kind of sucks, that's an awesome feature of the Android version.