[aprssig] FYI: TIME SERVICE ANNOUNCEMENT SERIES 14 UTC TIME STEP

[Christensen, Eric]

From: fifth-cg-dlnm-bounces at cgls.uscg.mil on behalf of fifth-cg-dlnm at cgls.uscg.mil
Sent: Tue 20-Dec-05 08:57
To: Fifth-cg-dlnm at cgls.uscg.mil
Subject: TIME SERVICE ANNOUNCEMENT SERIES 14 UTC TIME STEP


U.S. NAVAL OBSERVATORY WASHINGTON, D.C. 20392-5420 July 27, 2005 No. 69 TIME SERVICE ANNOUNCEMENT SERIES 14 UTC TIME STEP

 

1. The International Earth Rotation and Reference Systems Service (IERS) has announced the introduction of a time step to occur at the end of December, 2005.

2. Coordinated Universal Time (UTC) will be retarded by 1.0s so that the sequence of dates of the UTC markers will be:

2005 December 31 23h 59m 59s

2005 December 31 23h 59m 60s

2006 January 01 0h 0m 0s

3. The difference between UTC and International Atomic Time (TAI) is:

from 1999 01 Jan, UTC to 2006 01 January, UTC: TAI-UTC= +32s from 2006 01 Jan, UTC until further notice: TAI-UTC= +33s 4. Information regarding current and predicted values of UT1-UTC is provided in IERS Bulletin A.

5. UTC and all time scales based on UTC 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 sub frame 4, page 18 of the navigation message transmitted by satellites will change.

Before the leap second

GPS-UTC = +13s (i.e., GPS is ahead of UTC by thirteen seconds) After the leap second GPS-UTC = +14s (i.e., GPS will be ahead by fourteen seconds)  

 

Nauticast Navigations system GmbH, the manufacturer of the NAUTICAST and NAUTICAST2 (certificate pending), Nauticast X-Pack DS (USCG Type-Approval Nr. 165.155/0007/0), also know as the ACR Global Watch UAIS, Global Watch UAIS2, Raytheon RM 808 AIS, Marine Technology Bridge mate AIS, has issued a Technical Bulletin alerting customers that the additional second will affect the performance of these systems, unless a manual re-synchronization takes place between January 1 and January 2 (visit http://www.nauticast.com <http://www.nauticast.com/> ).  

 

Mariners are advised to monitor any system that relies upon UTC (GPS, AIS, CELL PHONES etc., et al) for timing or positioning for possible anomalous operation because this "leap second" may affect the performance of other AIS units, as well as other electronic navigation systems.

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