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Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!petrus!karn
From: karn@petrus.UUCP
Newsgroups: net.space
Subject: Re: effect of SDI
Message-ID: <322@petrus.UUCP>
Date: Fri, 5-Apr-85 12:33:43 EST
Article-I.D.: petrus.322
Posted: Fri Apr  5 12:33:43 1985
Date-Received: Sat, 6-Apr-85 03:21:58 EST
References: <1353@mordor.UUCP> <268@faron.UUCP>
Organization: Bell Communications Research, Inc
Lines: 11

Regarding GPS, I read recently that a clever new civilian use has been
found that can give centimeter accuracy to surveying measurements.
The scheme does Very Long Baseline Interferometry (VLBI) using the
GPS satellites.  The receivers treat the satellites as simply more powerful
noise sources than the galactic sources normally used for VLBI, and therefore
don't need to know the actual code sequences.

The major limitations to accuracy under this scheme is atmospheric
refraction, and uncertainty in the precise orbits of the satellites.

Phil