[LEAPSECS] presentations from AAS Future of Time sessions

[Warner Losh]

On Jan 13, 2014, at 2:30 AM, Poul-Henning Kamp wrote:


> In message <BE5B1909-2417-4F36-B5CC-AA2B35E4556D at bsdimp.com>, Warner Losh write

> s:

> 

>> http://www.dtic.mil/dtic/tr/fulltext/u2/a280955.pdf Perhaps these 

>> documents will prove useful in working out TAI's origin, but it seems 

>> that LORAN-C started in 1958, and so did TAI time's EPOCH, so there's a 

>> strong inference to be made at the connection between the two... 

> 

> Actually, I recall somebody mentioning that to me, it may have been

> Dave Mills long time ago when I worked on his LORAN-C receiver.


The other PTTI docs I posted show that the Navy (USNO) was ordered to provide technical assistance to the USCG in synchronizing the master clocks at the LORAN stations in 1960. At that time, USNO, NBS and AMR were the only games in town in the US. It gave reference to the order to effect that, but I've not been able to find the referenced order in my google searches anywhere except in the PTTI paper that references it.

The early PTTI docs on time transfer talk about the seasonal delays introduced in the LORAN-C signal propigation on the order of microseconds and how that hampered synchronization of time between the European labs and the American labs.

The earliest measurements I can find on LORAN signals is from the 1970 PTTI paper http://tycho.usno.navy.mil/ptti/1970papers/Vol%202_04.pdf titled "Precision Time and Time Interval Dissemination via the LORAN-C System." which publishes a summary of R and sigmal values from Feb 1, 1968 for the east coast system (see page labeled 49). The tables reference that it is analysis of published data, but I can't seem to find this data on the internet today...

Warner