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Originally Posted by VW
Actually your first statement that I remember is that aGPS is cellular triangulation, which it most certainly is not, although it does USE triangulation for satellite almanac info etc.
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While "aGPS technology" technically can provide some data to the end-device about sat orbits and conditions to help the "real GPS" compute a location, in the real world it's not how it's used on cell phones. An GPS/aGPS enabled cell phone will first try to use the stand-alone GPS sat data to compute a location, if it can't will fall back to aGPS that strictly uses the carrier's network to compute a location. Here's a real-world description taken from one of the carrier's software developer's websites:
"How does Assisted GPS (AGPS) work?
AGPS combines the accuracy of GPS technology, CDMA Network Triangulation (AFLT) and Cell Site Location Technology. This ensures wireless devices can be found with more reliability than traditional GPS services, even in the most challenging environments. Bell Mobility’s AGPS solution
will first attempt to use GPS satellites to locate the Assisted GPS Ready wireless device (within 150m in most circumstances) and if unsuccessful will begin to
fall back on a variety of network based location technologies.
http://developer.bellmobility.ca/lbs/pre-index.asp
You can go back and forth quoting all the theory you want, I'm talking about the real world application of the technology.