http://www.ifixit.com/Teardown/iPad-3G-Teardown/2374/1

Scroll down, it's on the communications board. Broadcom A-GPS BCM47501UBG. This is from the initial iPad, the iPad 2 may change chips.

*edit* and the datasheet in PDF form, confirming the chip tracks up to 24 satellites (and not cell towers).


Edited by drakino (02/03/2011 21:00)