From: "Perry E. Metzger" <perry@piermont.com>
Date: Sun, 14 Apr 1996 01:35:24 +0800
To: Paul_Koning/US/3Com%3COM@smtp1.isd.3com.com
Subject: Re: No matter where you go, there they are.
In-Reply-To: <9604112026.AA8065@>
Message-ID: <199604111901.PAA21576@jekyll.piermont.com>
MIME-Version: 1.0
Content-Type: text/plain



Paul_Koning/US/3Com%3COM@smtp1.isd.3com.com writes:
> Suppose I want to pretend that I am 1000 feet closer to satellite 4 than 
> I really am.  Simple, I take the signals from all the other satellites
> and delay them by 1 microsecond.  That looks like a 1 microsecond
> local timebase error together with a 1 microsecond delay reduction
> to satellite 4.

Aren't things even worse? Since the satelite signals are not
authenticated with anything like public key methods, couldn't I just
synthesize a signal appropriate to any spot on the planet, knowing the
positions of the satelites relative to that spot?

Perry