From: Phil Karn <karn@qualcomm.com>
Date: Tue, 21 Jun 94 18:01:19 PDT
To: frissell@panix.com
Subject: Re: Another Cellular Vict
In-Reply-To: <199406191329.AA18599@panix.com>
Message-ID: <199406220101.SAA00348@servo.qualcomm.com>
MIME-Version: 1.0
Content-Type: text/plain


>Bell Atlantic already announced a joint venture with one of the electronic 
>navigation companies to supply drivers with position info using cellular 
>triangulation.

Not to mention our very own Omnitracs service, which uses spread
spectrum ranging via satellite to report the position of every mobile
user to roughly GPS accuracy (without actually using GPS). So far the
trucking companies to whom we sell this stuff have been pretty
enlightened in how they use this information.

We've also discussed adding position location to our CDMA cellular
system, although that wasn't originally a design consideration.
Depending on how far you go with modifying the existing system,
and depending on local terrain, you could locate a user somewhere on
a circle around a given cell (by round trip time measurements from
cell to mobile and back) or perhaps to a specific point by multi-cell
delay measurements during a handoff.

Which suggests a "stealth" phone that randomly dithers its round trip
delay a la GPS selective availability...

Phil