Re: A lurker surfaces

From: Ashley Yakeley <ashley_at_SEMANTIC.ORG>
Date: Tue, 2 Jan 2007 11:56:30 -0800

On Jan 2, 2007, at 11:40, Warner Losh wrote:

> The second technical problem is that the length of a second is
> implicitly encoded in the carrier for many of the longwave time
> distribution stations. 10MHz is at SI seconds. For rubber seconds,
> the broadcast would drift into adjacent bands reserved for other
> things.

At 1000ns, the carrier would drift by 10Hz. Surely the bandwidth is
big enough for that?

> Also, GPS would have to remain in SI seconds. The error in GPS time
> translates directly to an error in position. Approximately 1m/ns of
> error (give of take a factor of 3). Rubber seconds would require that
> the rubber timescale be off by as much as .5s. So GPS has to remain
> in GPS time (UTC w/o leap seconds, basically). That means that the
> rubberness of the seconds would need to be broadcast in the
> datastream.

GPS is TAI. I'm not proposing abandoning TAI for those applications
that need it.

Ashley Yakeley
Received on Tue Jan 02 2007 - 11:57:02 PST

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