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Re: Vonage Selects TCS For VoIP E911 Service

  • From: Andre Oppermann
  • Date: Wed Jul 20 06:27:56 2005

Mikael Abrahamsson wrote:
On Wed, 20 Jul 2005, Andre Oppermann wrote:

To sum it up: Using GPS to geo-locate VoIP phones or adapters is broken by design.
No, it isn't. Relying on satellite connectivity to do so broken, but that's not how it works anymore. Did you even read the article regarding indoor GPS that I posted earlier in the thread?
I did but those ground based transmitters are only for improving accuracy
by sending you the position delta determined vs. real for that region. It
doesn't help if you don't receive a GPS signal. That ain't satellite radio
which is being terristrically re-broadcast.

For more information have a look the descriptions of these augumented GPS
systems:

 http://en.wikipedia.org/wiki/GPS#Techniques_to_improve_GPS_accuracy
 http://en.wikipedia.org/wiki/Trilateration

To sum it up: Without having good GPS reception you can't do trilateration
and without it you can't apply any accuracy improvements.

--
Andre