View Single Post
  #14   Report Post  
Old January 20th 08, 11:44 AM posted to rec.radio.shortwave
Geoffrey S. Mendelson Geoffrey S. Mendelson is offline
external usenet poster
 
First recorded activity by RadioBanter: Jun 2006
Posts: 487
Default NIST Considers East Coast WWVB Broadcast


John Kasupski wrote:

Joke's on them. GPS time is implemented by the atomic clocks in the
GPS ground control stations and the GPS satellites themselves. Since
it is not updated with leap seconds, GPS is currently ahead of UTC by
14 seconds.


I answered that with:

That's a software bug. For location purposes, a leap second is a
very bad thing when it happens. So it's better for GPS to ignore
it, and if you really need accurate time, compenstate for the extra
seconds in the routine that takes the GPS data and converts it to
whatever you are using it for.


According to:
http://www.eecis.udel.edu/~mills/leap.html

The NTP network automaticly deals with the difference between NTP and
GPS times. The web page also states:

While of less use to the computer timekeeper, the Global Positioning
System (GPS), which is widely used to disseminate standard time, has its
own timescale. The GPS timescale is syntonic with TAI, but at a fixed
time offset of -19 s from that timescale, apparently because the final
system design review was in 1980. GPS clocks typically convert from GPS
to UTC for external readings.

So someone already thought of it, and it is no longer, and may never
have been an issue.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at
http://geoffstechno.livejournal.com/