[time-nuts] Can eloran Backup GPS?
jimlux at earthlink.net
Sun Sep 9 10:43:24 EDT 2018
On 9/8/18 4:52 PM, paul swed wrote:
> Hello to the group I won't quote figures here but did indeed help UrsaNav
> do testing. Hey 90 days with a HP 5071 that was a sweet deal at the cost of
> some power.
> They do send corrective data in the signal from reference sites and that
> helps propagation corrections in the receive software.
> It was impressive and even in buildings no less. Its been a while so thats
> why I don't want to quote figures.
> I sort of thought all of this would have been resolved by now. But nope not
> until the S.. hits the fan and finger pointing starts.
> I do know the other satellite system lightspeed? is trying to become an
But here's the problem - if "the network" is wiped out, how do you send
the correction information?
I suppose you could have a low rate network (i.e. not "the internet")
and for the most part, the propagation corrections (whether using 60kHz,
Loran, Omega, or GPS) can be done with "climatology" - time of day and
time of year.
BUT - if we're talking about a Carrington event or similar, a series of
high altitude nuclear bursts - the propagation is going to be totally
If we're talking about a evil-doer taking down GPS AND "the network"
together, but not perturbing the ionosphere, there may be other things
to worry about - the network carrying "time" is also carrying all those
high value transactions, phone calls, etc. and that's probably a bigger
business disruption than losing network sync.
So I think GPS actually works pretty well - it will provide good sync
for any non-global disaster. Likewise, a "campus" network will be able
to stay synchronized, because they've got wired connections.
In a local disaster (hurricane, earthquake) it's likely that business
has been disrupted by the disaster sufficiently that time sync is less
More information about the time-nuts