Using a signal-processing scheme known as real-time kinematics*, or RTK, they can boost the accuracy of a GPS reading from about 3 meters to within just a few centimeters.As I recall, the public GPS signal is deliberately obfuscated by the US government so that the military can have more accuracy than anyone else. Update-- it turns out I was right, but it's old news: signal degradation was turned off May 1, 2000.
That was one of the reasons there's a European satellite system in progress.
I hadn't heard that there are also planned Chinese, and Indian GPSs, and a Russian system-- GLONASS-- in operation. Correction about GLONASS thanks to ckd.
I don't have a feeling for how many GPSs would be needed in some theoretical sense to get enough redundancy, but one seems kind of skimpy.
Anyway, at least I was right about one thing-- we're getting more and more information from less data, this is a very cool trend, and I'm still not seeing science fiction about it. Or have I missed some?
First link thanks to andrewducker.
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