"Ray Drouillard" wrote:

:
:"pervect" wrote in message
.. .
: On Sat, 20 Dec 2003 18:15:56 +0000, ess (phil
: hunt) wrote:
:
: On Fri, 19 Dec 2003 13:43:49 -0500, Ray Drouillard
wrote:
:
: Also, since it's not encrypted, it can be spoofed using a local
: transmitter
:
: That doesn't logically follow; it's possible to make non-encrypted
: data that can't be faked, you just use a digital signature.
:
: If you don't go to spread-spectrum, your radio links will probably be
: jammed. (Solution - go to spread spectrum).
:
: Spread spectrum signals will be difficult to separate from noise,
: except at very close range, where the total power level is noticable
: above the broadband noise.
:
: I'd still rate a radio location system using spread spectrum
: transmitters as rather vulnerable, because the transmitters have to
: remain in a fixed location for the system to work, and would be prime
: targets.
:
:You don't necessarily need stationary transmitters. After all, the GPS
:transmitters aren't stationary.
:
:If the transmitters transmit their locations to the receivers, the
:receivers can do the necessary calculations to get a fix.

Ok, you're now trying to reinvent GPS, but without the satellites.

How do the transmitters know THEIR locations with precision if they
are moving?

--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn