Newsgroups: comp.robotics
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From: spofford@dps (John Spofford)
Subject: Re: GPS Accuracy?
Message-ID: <1993Aug24.145139.22491@den.mmc.com>
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Organization: Martin Marietta Astronautics, Denver, CO
References: <1993Aug23.010118.29544@aio.jsc.nasa.gov> <SSINGH.93Aug23113130@wilbur.frc.ri.cmu.edu> <25be5l$92f@constellation.ecn.uoknor.edu>
Distribution: usa
Date: Tue, 24 Aug 1993 14:51:39 GMT
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>Mike Ross:
>Does anyone know if I could get around 1 cm repeatibility if I
>averaged the signal?  I theorize the intentionally added error
>is randomly dispersed about zero if taken over a long enough period.
>Note that I want repeatibility, not accuracy, in the centimeters.

I believe that is how surveyors use GPS.  It takes both a differential
setup and an averaging period (not sure how long).

>Robert W Murphree:
>can GPS signals be reliably recieved in metal buildings?

No way.  Even trees obscure the satellite transmissions.  If you are
indoors, you can set up your own RF or optical positioning system.

I work on a project where we use differential GPS on a land vehicle
and it is difficult to get a few meters accuracy while in motion.

---
John Spofford  (spofford@den.mmc.com)        "standard industrial disclaimer"
