What differences are there between Core Location on the iPod Touch and iPhone?

I g开发者_运维百科uess the GPS chip is only there on the iPhone. But for some reason, my iPod Touch seems to know my position anyways even without GPS chip. So what does that mean for Core Location? What do I have to consider when using Core Location both on the iPhone and iPod Touch? What are the differences?

I believe the API is the same. All that differs is the accuracy of the location that gets returned to you via the API.

the iPhone uses the GPS to get a pretty accurate lock on your location, whereas the iPod Touch uses IP-Location or Wifi-Triangulation technology, which is less accurate than the iPhone's GPS.

The iPod touch uses this method for Core Location information

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

-t

The iPhone uses a technology called A-GPS (the A stands for "assisted"), whereby the the cellular network and WiFi networks assist the GPS chip in determining your location. Depending on your location, this might result in a more accurate triangulation of your position.

While the iPod touch can't use GPS satellites or cellular towers to determine your location, it can use WiFi, so thats how your iPod touch knows where you are.

As far as the CoreLocation APIs go, there shouldn't be a difference between the devices, however accuracy will probably be lower and less consistent on the iPod Touch.