[ntp:questions] Re: no more leap seconds?

David L. Mills mills at udel.edu
Thu Aug 11 02:51:10 UTC 2005


Now you are in trouble. You have surfaced and now the hombres know you 
read the comics. However, and not withstanding the wisdom of your 
observation and without specific knowledge of WAAS principles, GPS 
reckons to TAI and so would I not assume WAAS?


Rich Schmidt wrote:
> Moi, regarding your "IMHO" I must say your opinions are deservedly
> humble. You lack a basic understanding of Earth rotation and lunar
> tides, for a start. Regarding "critical systems"
> and the need for precise time, keep in mind, in electronic navigation
> time <==> position. One nanosecond = 1 foot. One second = 1 billion
> feet, i.e., most of the way to the Moon. There are indeed critical
> systems that require amazing time accuracy.  Of the systems we can talk
> about, FAA's WAAS is one. Imagine trying to land a plane via WAAS if
> your coordinates are off by a few tens of meters!  Dr. Klepczynski is a
> former Naval Observatory Time Service Director and an FAA consultant,
> and is extraordinarily informed.
> GPS satellites do not "navigate on the stars". They do not navigate any
> more than the Moon navigates.
> The estimate of a need for a "leap hour" about the year 2600 is based
> on current analysis of historical observations of the Earth's rotation.
> This is found in the document USWP-7A/1 14 Jul 04 of the US Working
> Party 7A, International Telecommunications Union (ITU). See my next
> posting for more details.  Rich Schmidt, Naval Observatory

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