[time-nuts] Leap Quirks

[Lux, James P]

On 1/3/09 1:34 PM, "James Cloos" <cloos at jhcloos.com> wrote:

> Warner> Yet another hazard of high precision time keeping that few
> Warner> people get right
>
> Part of what makes this list's name so appropriate is just how hard
> it is, all things considered.  That is also what makes it enjoyable.
>

And, now, add in trying to synchronize clocks on moving platforms where the
platforms move fast enough (or the relative timing requirements) are such
that relativistic effects are important.

I'm working with developing a "standard" for timekeeping for spacecraft
radios (since the radio receives the sync signal (e.g. GPS, TDRSS, or DSN),
and often has a very good oscillator (e.g. A USO) connected to it, it makes
sense to do time keeping there..)

You'd think that you could just do something like TAI, but there's a long,
long heritage of using other time scales of one sort or another, referenced
to various things.   All well and good for situations where you can
dereference the difference between spacecraft time and "whatever" time after
the fact (e.g. When you're looking at radar returns, or radio science data),
but kind of a pain when you're looking to do things in real time.

Jim