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
