David L. Mills wrote: > Danny & Co., > > I'm not a defender of any political agenda here, but I would like to > correct the general assumption, as evident in the interviews last night, > that the Galileo system is more accurate than the GPS system. The GPS L1 > signal available to the general public has a nominal accuracy (PDoP) of > 30 meters; however, with the L2 signal and P code with capable receiver,
The current reality of GPS+WAAS/EGNOS is _much_ better: I have documented that with good antenna placement (360-degree visibility, small ground plane, no multipath), it was possible to monitor a single position in southern Norway over a two-week period last summer, with 67% of all measurements within about 1 m, 90% within 2 m, and 95% within 2.7 m. Excepting a single 30-second outlier period (with position errors up to 30 m), the worst offset I measured during this period was just over 3 m. > it has a nominal PDoP of one meter, comparable to Galileo. The P code is > available only to the USA military at present. I would assume once > Galileo reaches operational status there is no need to keep the P code > secret. > > Folks might forget the Russian GLONASS system, which is very similar to > GPS and Galileo, has been around for over twenty years. It is not clear > how long it will last or whether it can be maintained to the order of > GPS and Galileo. As I mentioned in my previous message, Ashtech makes combined GPS+Glonass receivers, they received a series of patents for this back in 1999: http://products.thalesnavigation.com/en/news/releases/viewRelease.asp?id=130 Terje -- - <[EMAIL PROTECTED]> "almost all programming can be viewed as an exercise in caching" _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
