[time-nuts] NIST

[Peter Laws]

On Mon, Aug 13, 2018 at 8:52 AM Peter Laws <plaws0 at gmail.com> wrote:


> I have yet to hear anyone make a case for retaining the HF system that
> isn't backed by nostalgia.

Still looking for this.  Most of the "OMG IF WWV GOES AWAY MILLIONS
WILL DIE" posts (elsewhere, not here ... quite ...) are the type of
hysteria that is usually reserved for, I don't know, the EMP folks.
:-)


> As for solar flares taking out the various GNSSs ... wouldn't a solar
> flare only take out the vehicles that were on the "sunny" side of the
> Earth?  Wouldn't the (approximately) half of the SVs that are in the
> Earth's shadow be unaffected?  Serious technical question - I have no
> idea.

One of the responses to my initial message pointed out that the
effects of solar flares and CMEs take a while to get from Sol to Sol
III and don't arrive all at once, so potentially all GNSS spacecraft
could be affected.

Since then, I've been poking around for papers on the effect
(observed, potential, theoretical) of these events on the Navstar or
other GNSS constellations but am not having much luck.  I assume it's
because I'm not putting the right magic incantation into the google
machine.

Anyone got some cites?  Looking for the effect of solar flares and
CMEs on the spacecraft themselves and not how the GNSSs can be used to
measure the effects on the ionosphere, etc (those seem plentiful).
IOW, I'm curious about the resiliency of the systems to solar events.

I did note that at the time of the 1989 solar event that took out a
lot of Hydro Quebec's grid, only the "Block I" experimental GPS "SVs"
were in orbit.  Well, maybe a couple of the later ones - the
operational constellation started launching about a month before that
flare.

As I said initially, I'll be sad if WWV* goes away but it won't affect
my life in any measurable way that I can see.  I mean, other than the
mantle clock slowly losing time.

-- 
Peter Laws | N5UWY | plaws plaws net | Travel by Train!