The precision of cellid is location specific as it depends on cell size. It depends on the arrangement and distance between the towers being used to locate you. Think geometry. The longer the sides of a triangle the greater the area.
That fellow might have been a GSM expert but clearly he wasn't an LBS or CDMA expert. One major benefit for current CDMA networks using cellid is that the base stations operate synchronously. They emit code sequences at exactly the same time, so there's no need for after collection synchronization as is the case for GSM.
...Debi
On 4/10/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]
> wrote:
I think this is a great question. I talked to a gentleman from South Africa
last year at Where 2 who claimed to be a GSM expert. He said that GSM can
locate you within something like 3 meters with no GPS support just using
the towers, and that this was built into the GSM spec. He spoke of a case
in South Africa where they located some sort of criminal using the GSM
records.
He said that CDMA on the other hand, cannot locate so precisely.
So, to me, A-GPS was designed to make CDMA users locatable to the same
degree as GSM.
As an aside, does anyone know which type of cell phones are more lethal?
Roger
Original Message:
-----------------
From: Ian | Urban Mapping [EMAIL PROTECTED]
Date: Mon, 10 Apr 2006 01:42:23 -0400
To: [email protected]
Subject: [Geowanking] E911 // cellular trilateration accuracy
At the risk of asking (another) obvious question, I continue my naïve streak
on this listserv…
I've heard very different reports of how accurate cellphone tracking is—the
FAA mandates something like 50% of calls must be traceable to within a range
of 30m but I've heard some mobile pros say they've heard of it getting as
good as several feet. Obviously this varies depending on geography (urban,
rural, topography), but does anybody have any idea how the US wireless
carriers stack up? And how does this compare to phones with GPS?
Ian White :: Urban Mapping LLC :: <mailto:[EMAIL PROTECTED]>
[EMAIL PROTECTED]
120 West 45th Street 20th Floor :: New York NY 10036
Tel.212.242.8267 :: Fax.866.385.8266 :: www.urbanmapping.com
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