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    Leap seconds a navigational hazard, says expert
    From: Paul Hirose
    Date: 2003 Aug 8, 12:10 -0700

    The Guardian has an article about the debate in the technical
    community on leap seconds. Some are worried the divergence of UTC with
    respect to other time scales will cause a crash some day, figuratively
    if not literally.
    
    "Widening gaps between GPS time used by aircraft navigation systems
    and the time used on the ground could generate confusion between a
    plane's report and actual position, he says, and so increase the risk
    of collision. A complicated situation will get more complex when
    Europe launches its own GPS system, Galileo, which will be based on
    yet another version of time.
    
    "Computer software converts between the different timescales used.
    'But if anybody ever makes a mistake there's going to be a big
    problem,' Mr Klepczynski says. His solution is to scrap the leap
    second, effectively merging atomic time and universal time. This is
    also the proposal being considered by the time lords of the ITU."
    
    http://www.guardian.co.uk/uk_news/story/0,3604,985020,00.html
    
    
    If that becomes reality, celestial navigators will eventually have to
    begin applying the UT1 - UTC correction. Currently the leap seconds
    keep that difference below 1 second. The value in tenth seconds is
    transmitted by radio time stations using a pattern of double ticks
    after the beginning of each minute. However, the code has no provision
    for offsets of 1 second and more.
    
    Right now Earth is about .35 seconds behind UTC. A year from now it
    should be about .42 second behind, according to IERS Bulletin A.
    
    http://maia.usno.navy.mil/
    http://tycho.usno.navy.mil/leapsec.html
    
    (Windows users - some documents on these pages may not display
    properly with Notepad. Use Wordpad to view them.)
    
    
    

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