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 ian@urbanmapping.com Date: Mon, 10 Apr 2006 01:42:23 -0400 To: geowanking@lists.burri.to Subject: [Geowanking] E911 // cellular trilateration accuracy At the risk of asking (another) obvious question, I continue my naove streak on this listserv Ive heard very different reports of how accurate cellphone tracking isthe FAA mandates something like 50% of calls must be traceable to within a range of 30m but Ive heard some mobile pros say theyve 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@urbanmapping.com> ian@urbanmapping.com 120 West 45th Street 20th Floor :: New York NY 10036 Tel.212.242.8267 :: Fax.866.385.8266 :: www.urbanmapping.com -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ . _______________________________________________ Geowanking mailing list Geowanking@lists.burri.to http://lists.burri.to/mailman/listinfo/geowanking ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE [demime 1.01d removed an attachment of type application/pgp-signature which had a name of signature.asc]