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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