Has the GPS chip been upgraded in the iPhone 4S? How does it compare to the 4 and 3GS?
The iPhone 4s, and the most recent iPhone 4 (Verizon) don't use a discrete GPS chip, as it's integrated into the baseband (Qualcomm MDM 6600). I believe the GPS chip in the iPhone 3GS used the Hammerhead II PMB 2540, or 2525 GPS chip. By integrating the GPS with the baseband it allows a smaller phone, less energy consumption, and cost less to produce.
iPhone 4s GPS [Qualcomm MDM 6600 Gobi]
The main improvements should be:
- Integration with Siri
- Updated antenna switching (spatial diversity)
- Improved TTFF and TTSF (fixes)
- Longer battery life (more energy efficient)
Since there is no official iPhone 4S delivered, I think there are no good records about this chip. All I can tell is the GPS accuracy improves with every iPhone model so far.
iPhone 3G sucks at GPS, iPhone 3GS was a bit better, iPad 1 was accurate, iPhone 4 is excellent as well as the iPad 2.
So as technology keeps improving, I guess the chips used in Apple's iPhones will too.