|
Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://www.arcetri.astro.it/~ranfagni/CD/CD_TESTI/LEAP.HTM
Дата изменения: Fri Jul 28 13:59:32 2000 Дата индексирования: Sun Sep 12 16:50:58 2010 Кодировка: Поисковые слова: п п п п п п п п п п п п п п п п п п п п п п п п п п п р п |
U.S. NAVAL OBSERVATORY
WASHINGTON, D.C. 20392-5420
July 23, 1998
No. 64
TIME SERVICE ANNOUNCEMENT SERIES 14
UTC TIME STEP
1. The International Earth Rotation Service (IERS) has announced the
introduction of a time step to occur at the end of December, 1998.
2. Coordinated Universal Time (UTC) will be retarded by 1.0s so that
the sequence of dates of the UTC markers will be:
1998 December 31 23h 59m 59s
1998 December 31 23h 59m 60s
1999 January 01 0h 0m 0s
3. The difference between UTC and International Atomic Time (TAI) is:
from 1997 01 Jul, UTC to 1999 01 January, UTC: TAI-UTC= +31s
from 1999 01 Jan, UTC until further notice: TAI-UTC= +32s
4. The insertion of one leap second will be evident by the change of
sign of the DUT1 correction which will become positive. Extrapolated
values of DUT1 are distributed weekly in the IERS Bulletin A.
5. All coordinated time scales will be affected by this adjustment.
However, Loran-C and GPS will not be adjusted physically. Times of
Coincidence for LORAN-C are available on the Time Service Web Page
(http://tycho.usno.navy.mil/loran.html). For GPS, the leap second
correction contained within the UTC data of subframe 4, page 18 of
the navigation message transmitted by satellites will change.
Before the leap second
GPS-UTC = +12 (i.e., GPS is ahead of UTC by twelve seconds)
After the leap second
GPS-UTC = +13s (i.e., GPS will be ahead by thirteen seconds)
DENNIS D. McCARTHY
Director
Directorate of Time
Time Service Dept., U.S. Naval Observatory, Washington, DC