[gpsd-dev] [PATCH 2/5] Update and cleanup the Time Sources section

[Sanjeev Gupta]

Add refernce to BIPM Circular T (not WWWB)
UTC(NIST) tracks UTC to less than 5ns
---
 www/time-service-intro.txt | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/www/time-service-intro.txt b/www/time-service-intro.txt
index 5f47210..6aca5c7 100644
--- a/www/time-service-intro.txt
+++ b/www/time-service-intro.txt
@@ -45,17 +45,18 @@ oscillator (popularly called an "atomic clock") used as a 
source
 standard by a national time authority.  By international agreement,
 the U.S. and other major national time authorities use primary
 standards based on electronic transitions between the two hyperfine
-energy levels of the ground states of cesium-133 atoms.
+energy levels of the ground states of Cesium-133 atoms.
 
-National time standards are synchronized (essentially, averaged) to
+National time standards are synchronized (essentially, averaged after 
+removing outliers and consistent errors) to
 yield an international reference called Universal Coordinated Time.
-National time standards, including the U.S.'s, are normally considered
-accurate to UTC within 20 ns <<WWVB>>.
+The US National time standard, UTC(NIST), normally tracks
+UTC to within 5 ns <<BIPM-T>>.  
 
-U.S. atomic clock time is propagated through the GPS system, which
-enables receivers to generate a pulse-per-second signal ("1PPS" or
-just "PPS") accurate to the top of the current UTC second within 50
-ns.
+U.S. atomic clock time (UTC(NIST)) is propagated through the GPS 
+system, which enables receivers to generate a pulse-per-second 
+signal ("1PPS" or just "PPS") accurate to the top of the current 
+UTC second within 50 ns.
 
 National time standards are also propagated through time radios. In
 the U.S., digital time signal is provided by WWVB in Colorado, driven
@@ -264,6 +265,8 @@ Procedures]
 - [[[WWVB]]] 
http://tf.nist.gov/timefreq/pubs/bulletin/pdf/1999OCT_TF_BULLETIN.pdf[NIST
 Time and Frequency Bulletin NISTIR 5082-10]
 
+- [[[BIPM-T]]] ftp://ftp2.bipm.org/pub/tai/publication/cirt/[See latest 
Circular T from BIPM]
+
 - [[[WWVBMAP]]] http://tf.nist.gov/stations/wwvbcoverage.htm[WWVB Coverage 
Area]
 
 - [[[SPECTRUMWIKI]]] 
http://www.spectrumwiki.com/wiki/DisplayEntry.aspx?DisplyId=51[Low Frequency 
Time Signals]
-- 
2.1.4