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[gpsd-dev] [PATCH 1/1] Add a NASA link, and some clarifications
From: |
Sanjeev Gupta |
Subject: |
[gpsd-dev] [PATCH 1/1] Add a NASA link, and some clarifications |
Date: |
Fri, 29 Nov 2013 00:57:37 +0800 |
---
timebase.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/timebase.c b/timebase.c
index 0de9204..656d0b8 100644
--- a/timebase.c
+++ b/timebase.c
@@ -59,14 +59,18 @@ the attendant confusion and fear that the formula would be
revised.
Since 1972, the start of UTC, the decision to have leap seconds means that
UTC ticks SI seconds. Every 86400 SI seconds, we declare a new day, and
-we let the error (UT1 - UTC) build up (this is of the order of a few ms
-each midnight).
+we let the error (UT1 - UTC) build up. This is of the order of a few ms
+each midnight, not always the same way (think eartquakes that move the
+earth's crust).
Once the error has built up substantially, in a few years, we (and by
"we", I mean M Daniel Gambis at the IERS) declare that a future
day will have 86401 secs. This is the Leap Second. Note that this
often overcorrects, but if we wait a few months, the error will disappear.
+An animation of this process is available at:
+http://space-geodesy.nasa.gov/multimedia/EarthOrientationAnimations/UT1.html
+
Clear?
Two last things:
--
1.8.4.4
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