[Edit: Hmm... Looks like Giz has taken the article down. I've removed the broken link for the time being.]
Earlier today I posted some thoughts on how the new iPhone’s GPS might make the Nike+iPod system obsolete. Right on cue, Gizmodo takes a closer look at the iPhone’s A-GPS (assisted GPS):
The term aGPS or A-GPS itself has many slightly different meanings, but in this case, location is determined with a combo of GPS, and cell towers—plus public Wi-Fi networks, if they’re available. All that data is crunched and neatly served up by the “assistance server.” (The nicest thing about the iPhone 3G’s setup is that the size of the “you are here” circle on a map indicates how accurate the guess is). Best news for campers: Unlike most phones, the iPhone’s A-GPS will still work without a cell signal.
There are even more advantages to A-GPS. The assistance server tells the phone where the satellites are in the sky, speeding up the search for a handful of space signals. Without assistance, you’d need to receive several really solid GPS signals for a decent period of time before getting a lock—the assistance server can take paltry, choppy ones and make use of them. Oh, and there’s that battery-life thing again. A-GPS is way more efficient.
I still haven’t decided whether I’ll be upgrading from my original iPhone right away, but details like these sure make it tempting.