Peter Laws wrote: > Looking for a reference on geographical diversity of Stratum 1 servers > (GPS appliances, in this case). We have two clocks now (an old Datum > TymServ with a Symetricom sticker) and another unknown brand. We'd like > to add a third at a completely different facility a mile or more away. > > What, other than the business continuity angle can I use? I'm assuming > it would be better to have the clocks separated from a GPS perspective, > too. > > Cites?
AFAIK geographical diversity does nothing to improve the time. It does add some robustness. If you are powered from different substations, good. Are the sites far enough apart to avoid being caught in the same flood, fire, earthquake, explosion, chemical/biological/radiologcal contamination, etc? There is something called "differential GPS" which can help refine position data; e.g. if you have GPS at both a known and an unknown location, the difference between readings can be used to refine the unknown position. The GPS computation of location, elevation, and time involves a system of four simultaneous equations which can be solved for time, lattitude, longitude, and elevation. Doing an extended "site survey" can refine your location and elevation. The better location data, the better the solution for time. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
