[time-nuts] National Positioning, Navigation, and Timing (PNT) Resilience and Security Act of 2015, H.R. 1678.

Fotis Georgatos kefalonia at gmail.com
Tue Mar 31 11:32:27 UTC 2015


Hi Bill,

On 28 March 2015 at 18:18, Bill Hawkins <bill at iaxs.net> wrote:

> It's been my experience that local daylight time change criteria are
> varied and fluid.
> How would a LORAN (or GPS) transmitter set the DST bit for everybody?
>

This is an interesting problem, and of only 300KBs solution size!

LORAN is sufficient to provide location resolution in itself so,
there should be some way to carry over the information (alike waas to gps
and so forth).
http://en.wikipedia.org/wiki/Tz_database
http://cs.ucla.edu/~eggert/tz/tz-link.htm -> Network protocols for tz data
-> Internet Engineering Task Force...

In principle, unlike GPS satellites, you may prioritize in any spare
bitstream capacity
the information which is relevant to local targets and use some extra
bitstream capacity
for the complete dataset (say, for a ship client which is navigating among
remote locations).
Because such information changes very very slowly, even very small bitrates
can help plenty.
Of course, this is only possible in our modern times because of cheap
silicon computing capability!

Leap second is a different story, luckily that has a global solution which
is geo-independent.

F.



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