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Richard Langley wrote:
> The underlying P-code (before encryption with the W-code to produce the
> Y-code) is the same on both L1 and L2 and civil receiver manufacturers have
> for years used this feature in dual-frequency receivers to provide
> the civil community with capabilties far superior to those typically required
> in military applications. As an example, at UNB we developed a machine
> control system with 2-centimetre accuracy.
Judging by some of the replies in this thread, it's important for folks
to know that these precise measurements are NOT locations on the face of
the earth, but rather distances between two sensors. One rarely sees
surveyors out with measuring tapes any more, they all have GPS-based
distance measurement devices. But, again, they are measuring the
difference between the location of two receivers based on the phases of
the received GPS signals, not decoding P-code signals.
Lu Abel
