Re: GPS questions

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Article #6908

#6908

From: Glenn A Sullivan
Date: Fri, 21 Aug 1992 03:53

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>arkusins@esseye.si.com (Andy Arkusinski) writes:
.......
> Each GPS satellite transmits a course acquisition (C/A) code that is unique
> to the satellite. This code is a pseudorandom noise (PN) code that repeats
> every millisecond.  PN codes have the attribute that the mathematical
> cross-correlation function between two PN codes is a large positive number
> when the two codes are identical, and close to zero otherwise.

I would expect there to be problems in discriminating among codes if very
short sublengths were tested for. For example, 1100111000 probably occurs
in all the codes. So once "trial correlation" happens, longer/entire pattern
matches must be done. What is a useful sublength to use, to adequately avoid
false trial correlations?
Allen Sullivan      gsulliva@enuxha.eas.asu.edu

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Path: arc1-ca.pugleaf.net!sparky!uunet!elroy.jpl.nasa.gov!usc!cs.utexas.edu!asuvax!ennews!enuxha.eas.asu.edu!gsulliva
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: GPS questions
Message-ID: <1992Aug21.035354.10587@ennews.eas.asu.edu>
Summary: What is the necessary length of GPS correlator
Keywords: GPS
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Organization: Arizona State University
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Date: Fri, 21 Aug 1992 03:53:54 GMT
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