Differences between version 12 and previous revision of NTPServers.
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| Newer page: | version 12 | Last edited on Tuesday, August 21, 2012 7:35:26 pm | by SamBailey | Revert |
| Older page: | version 8 | Last edited on Tuesday, August 14, 2012 3:49:16 pm | by SamBailey | Revert |
@@ -35,9 +35,9 @@
All three are Symmetricom S300 NTP servers, each connected to a differential GPS antenna on the roof and each with a rubidium oscillator to provide a stable clock in the event of an issue with the GPS signal. [more|http://ntp.net.nz/architecture/]
! The Measurements Standards Laboratory
-The standard for time in New Zealand is maintained by the Measurement Standards Laboratory, part of Industrial Research Limited. It is disseminated by various means, including 'pips' on several radio stations and
NTP.
+The standard for time in New Zealand is maintained by the Measurement Standards Laboratory, part of Industrial Research Limited. It is disseminated by various means, including NTP.
* <tt>msltime.irl.cri.nz</tt>
* <tt>msltime1.irl.cri.nz</tt>
* <tt>msltime2.irl.cri.nz</tt>
@@ -59,9 +59,9 @@
* <tt>nist1-sj.ustiming.org</tt> San Jose, California
* <tt>nist1-la.ustiming.org</tt> Los Angeles, California
* <tt>nist1.aol-ca.symmetricom.com</tt> Mountain View, California
-The US Naval Observatory (USNO) operates several stratum 1 time servers from it's Alternate Master Clock Facility (AMCF) at Falcon AFB, near Colorado Springs, on the same site as the GPS Master Control Station. These servers are referenced to a network
of hydrogen maser and caesium
standards that are synchronised with UTC(USNO)
via satellite. [more|http://tycho.usno.navy.mil/clocks.html]
+The US Naval Observatory (USNO) operates several stratum 1 time servers from it's Alternate Master Clock Facility (AMCF) at Falcon AFB, near Colorado Springs, on the same site as the GPS Master Control Station. These servers are referenced to UTC(USNO) which is comprised of
a large number
of caesium and
hydrogen maser standards in environmentally controlled vaults, spread across two sites linked
via satellite. [more|http://tycho.usno.navy.mil/clocks.html]
* <tt>tick.usnogps.navy.mil</tt>
* <tt>tock.usnogps.navy.mil</tt>
@@ -72,7 +72,29 @@
!! Stratum 1 Servers in Australia
The Australian National Measurement Institute (NMI) maintains the Australian time standard, UTC(AUS) using caesium and hydrogen maser standards. NMI maintains a number of NTP servers which are referenced to UTC(AUS). To use these servers, you need to register via email. [more|http://www.measurement.gov.au/Services/Pages/TimeandFrequencyDisseminationService.aspx]
+
+!!! Other Sources of Time in New Zealand
+
+!! Global Navigation Satellite Systems (GNSS)
+
+GPS time signals have an accuracy of ±10ns, making them the best option for most applications. The planned establishment of Galileo by the European Union and Compass by China will provide additional sources of time for compatible receivers.
+
+It's possible to sync a computer directly to the Pulse Per Second (PPS) output of a suitable GPS device using a serial or parallel port [more|http://gpsppssync.sourceforge.net/]. For better accuracy, there are PCI cards available with PPS inputs and/or built in GPS receivers. There are a variety of dedicated NTP servers available, some with internal oscillators that can maintain a stable clock if the satellite signal is lost.
+
+If you require better accuracy than GPS can provide, OmniSTAR provides GPS and GLONASS correction data via a worldwide network of geostationary satellites and reference stations.
+
+!! SW Radio
+
+It might be possible to receive the 5, 10 and 15 MHz signals broadcast from NIST's WWVH facility in Hawaii. WWVH continuously broadcasts a time code on a 100-Hz subcarrier. The time code presents UTC(NIST) information in Binary Coded Decimal (BCD) at a rate of 1 pulse per second. [more|http://www.nist.gov/pml/div688/grp40/wwv_format.cfm] [wikipedia|http://en.wikipedia.org/wiki/WWV_(radio_station)#Broadcast_format]
+
+!! FM Radio
+
+Radio New Zealand broadcasts UTC(MSL) time signals on many of it's stations every hour. They consist of six 'pips' of 1000 Hz tone, at one second intervals, the beginning of each pip marking the exact second. When a pip marks the exact hour, its length is doubled. When a leap second is inserted seven pips are broadcast.
+
+!! Digital TV
+
+Freeview transmits local time information using DVB-T at least once every 15 seconds with an accuracy of ±2s.
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See also [NTPNotes]
