Thread: why is the GPS missing in Action?
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lma is offline lma
2009-09-04 , 10:25
Posts: 2,802 | Thanked: 4,491 times | Joined on Nov 2007
#9
From the wikipedia entry I linked to above:

Assistance falls into two categories:
[...]
Calculation of position by the server using information from the phone.
* The assistance server has a good satellite signal, and plentiful computation power, so it can compare fragmentary signals relayed to it by cell phones, with the satellite signal it receives directly, and then inform the cell phone or emergency services of the cell phone's position.
Ie, the device does have a GPS receiver but doesn't calculate the position itself. It sends the raw data it gets from the "birds" (which may not be enough for the calculation anyway) to the assistance server, the server adds its own data, performs the calculation and sends the coordinates back. It's a bit useless unless you are in range of a supporting cell network, which is why a lot of people are wary of the term.

The N900 sounds like it uses the "good" kind of A-GPS, let's just hope it performs better than its predecessor.