[Geowanking] E911 // cellular trilateration accuracy
debi.jones at gmail.com
Mon Apr 10 10:16:49 PDT 2006
The most lethal phone is one that hits your head with enough force to crack
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
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.
On 4/10/06, roger at sylvanascent.com <roger at sylvanascent.com> wrote:
> I think this is a great question. I talked to a gentleman from South
> 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
> 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?
> Original Message:
> From: Ian | Urban Mapping ian at urbanmapping.com
> Date: Mon, 10 Apr 2006 01:42:23 -0400
> To: geowanking at lists.burri.to
> Subject: [Geowanking] E911 // cellular trilateration accuracy
> At the risk of asking (another) obvious question, I continue my naïve
> on this listserv…
> I've heard very different reports of how accurate cellphone tracking
> FAA mandates something like 50% of calls must be traceable to within a
> 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:ian at urbanmapping.com>
> ian at urbanmapping.com
> 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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