Re: PRA_fix

[rah@shipwright.com (Robert Hettinga)]

>   8-4-95. NYPaper:
>
>
>   "A Contract Is Awarded To Improve Navigation."
[snip]
>      The geosynchronous satellite would radio a correction
>      factor back to planes in flight, or any other user. The
>      plane would also receive signals from the G.P.S.
>      satellites, calculate a position, apply the correction
>      factor and fix its location.

This is called an active location system, and it was originally disigned by
G.K. O'Neill (The Princeton Physics Prof., Space Studies Institute founder,
the guy who came up with all those spiffy space-settlement ideas in the
late seventies -- see Babylon 5 for a picture ;-) -- and the inventor of
the mass driver, among other things), under the name of Geostar, in the
early 1980's. It's accuracy was supposed to be 6 inches in 2 dimensions,
and 6 feet in 3 diminsions.  The FAA didn't like it because they didn't
invent it, the DOD hated it because they wanted to commercialize GPS and
they didn't want anything so accurate for civilian purposes.  The
transponders were going to be beensy little things about the size of pagers
relying on high-energy burst transmissions.

ObCrypto/Privacy: It relied on a fast computer on the ground to calculate
where you were, it allowed short messages, and presumably it was going to
send them in the clear. It also had a "panic" button function, where
someone in trouble could summon help no matter where they were.

-----------------
Robert Hettinga (rah@shipwright.com)
Shipwright Development Corporation, 44 Farquhar Street, Boston, MA 02131
USA (617) 323-7923
"Reality is not optional." --Thomas Sowell
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