3G iPhone GPS?

The 3G iPhone will use a system similar to other cell phones - A-GPS. A-GPS use a combination of 3G connection and/or wifi-fi to triangulate your location. Unfortunately this setup isn't as fast as a real GPS unit (that uses GPS satellites)

More details on how this works here: Giz Explains: What You Didn't Know About the iPhone 3G's GPS

Thats really cool

Asum!

yeah! iphone!

Nor as accurate. Using the Maps feature and tracking my location while driving there were times I was shown as about 100 yards off the road. This may have been in an area with poor coverage, tho. If they triangulate from cell towers, they may not have been able to provide a closer fix on my location. At other times it was dead accurate.

I wonder if the type of gps can even support turn-by-turn?

Assisted-GPS (A-GPS) is an enhancement to plain vanilla GPS. The assistance it receives over 3G/WiFi helps it attain a fix faster than scanning for the GPS satellites alone. So it's "real" GPS.

My post may have left the impression that the iPhone doesn't have real GPS, but there is actually a real GPS receiver in it. You know you are using real GPS when the blue dot shows your location. If you use the Maps feature indoors where no satellite signal is available, the blue dot does not appear, but if you walk outside the accuracy improves greatly and the dot appears.

i have heard that there is supposed to be some applications to come out shortly that will allow turn by turn directions

The GPS isn't reliable on my iPhone when 3G is enabled. I live near Portland, but the GPS puts me in Houston.

hehehe very unreliable! maybe depends on the cellsite?

Yea, I heard about the rumor also.

if it only it worked correctly all the time.

Do you guy's think the G3 is worth buying? or should i get the old one beacuse it is a lot cheaper

Not the fastest GPS I've come across, but it helped in a pinch.