"Nothing I said contradicts anything in the references you
    cite."

A statement was made earlier to the effect about a 'common
misconception' regarding the higher chip-rate P-code
and I have laid down authoratative material and cites
countering that statement. Now we all know that the PPS
(Precision Positining Service using the higher chip-rate
P-code) has been used and is the *more* accurate GPS signal
emanating from the NAVSTAR birds (making use of that is
another matter - as one must be granted access to it).

Even the documents I cited show a greater absolute accuracy
(using GPS alone) with PPS (using P code) versus SPS (Standard
Postioning Service using the civilian-acessable "C/A code").

Matter closed.

RF Jim



----- Original Message -----
From: "Dave Tweed" <pic@DTWEED.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Saturday, November 23, 2002 1:50 PM
Subject: Re: [OT]: (Report of) GPS anomalies


> RF Jim <jvpoll@DALLAS.NET> wrote:
> > "Dave Tweed" expressed the following thought:
> >     "but it was still talking about intentions, not practice."
> >
> > I don't see where you can come to a conclusion like that when the
> > document reference I cited uses phrases like "The GPS is a ..."
> > and "GPS provides ..." and "The satellites transmit ..".
> >
> > These are statement of fact, not 'wish lists' or desires for system
> > capabilities ...
>
> Look, I don't see what you're getting so hot about. Nothing I said
> contradicts anything in the references you cite.
>
> However, everyone seems to assume (and you stated) that a C/A-only
receiver
> CANNOT perform as well as a P-code receiver, all other things being equal,
> based soley on the chip rate of the two signals. Although this might have
> been the case in the early days, it is simply not true now, and has not
> been for quite some time. Furthermore, the availability of DGPS and WAAS
> have all but completely obliterated the performance differences between
> even inexpensive C/A receivers and P(Y) receivers, which is one of the
main
> reasons that the government has turned off SA pretty much permanently.
>
> In fact, SA was turned off for a good part of the Gulf War, because the
> military couldn't get their hands on sufficient quantities of P(Y)
> receivers, and was issuing COTS C/A receivers to many of the ground
forces.
>
> And that's the last I'll contribute to this thread.
>
> -- Dave Tweed
>

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