IPhone 4.0 GPS and camera

Question

Hi,
I have two questions about the iPhone 4.0. I would like to get input from users.
1 - GPS
I read that the iPhone 4.0 has the same GPS chip than the iPad. Is it a stand alone GPS? I mean... if I have no phone data link and no Wi-Fi, can I still use the GPS? Or is it like older models where it uses triangulation with the 3G?
2 - Camera
Ok, there is a flash on the iPhone 4.0 for photography. My question is the following: can you change the aperture or shutter speed with the built-in application for taking photos or a third-party app?
Thanks.

Answer 1

Yes, really.
The iPhone includes a dedicated GPS receiver - always has, and also uses A-GPS or assisted GPS. The assisted part via cell tower location or wi-fi helps to speed up the initial GPS acquisition only.
When you use a GPS system and you turn it on, it needs to find orbit and clock data for the relevant satellites, this in turn results in what is called TTFF, or Time To First Fix—how long before you get your location pinpointed. This initial TTFF is often called a “cold start” and on SiRF III systems (the latest GPS systems available), it can take anywhere from 30 seconds to a couple of minutes to acquire a signal. That time is dependent on your location, amount of interference and horizon information: open fields are faster than canyons or urban environments where buildings can interfere with the satellite-receiver line of site.
But when you use assisted GPS this whole process is much faster. Very often cellular network towers have GPS receivers (or a base station nearby) and those receivers are constantly pulling down satellite information and computing the data. This data is then passed on to the cellular phone (when requested) and acts like a “cheat” since the relevant satellites to your location are already identified and all that GPS computations is handled by 3rd party computers.
Maps data is not stored locally with the Maps app included with the iPhone. An internet connection is required to download the maps data for a particular location. If you don't have cellular service, the GPS radio will work but the initial acquisition will take longer and unless you are using a GPS app with maps data stored locally on the iPhone, you won't have maps data available.