Clarification about the term "GPS Shutdown"

[kashe]

Compared to what? More haste, less speed.


Maybe, but thats irrelevant. Right now today I could navigate with just a
reasonably accurate watch.


If you had a map, you'd have noticed that you were *already in khartoum*.

Oops, I retract my prior blub, blub comments -- didn't notice
the "E".

 

[kashe]

Air travel, surveying, road transport, other types of navigation,
timekeeping, and so on.


Their cumulative utility to society in general.

Individual human lives do not have infinite value. Their value must be
balanced against many other variables. That's how things work in the
real world.

In science fiction, Captain Kirk might well put himself and his entire
crew at serious risk of death just to save one crewmember. In real
life, you let the crewmember die. Sometimes these policies are even in
writing. That's why not everyone can sit near an emergency exit on a
plane, and why passengers in wheelchairs are evacuated last.

Where do you live? Where I work, people in wheelchairs are
assigned a couple or three people whose defined duty is to evacuate
the person in the wheelchair, leaving the wheelchair behind.

 

[kashe]

As for auto navigation systems, the world will survive quite nicely for a
few days or weeks without them. maybe people would be "forced" to reacquire
the fine old art of map and compass navigation.

Until there's a much larger installed base, I doubt that
failure of auto navigation will be all that big an issue. 95% of the
male population still refuses to stop to ask for directions.

Plaintive question from my mother-in-law -- Bill, if we're
going home from Monterey to San Francisco, what's the ocean doing on
my side of the car?

 

[kashe]

Yes.

It's called Galileo.

Which, according to the document in question, the US
government intends to shut down as well (given the capability, which
they will try to acquire) -- it's that short phrase containing the
word "similar" or "other".

 

[Mxsmanic]

I recall an account of a man who sailed a converted St. Pierre
dory across the Atlantic to Europe using only a fairly good compass
and a plastic Davis training sextant which cost only about $35 at the
time, some thirty years ago.

As long as he stays at the same latitude and departs from the right
point, it's easy enough to do. Mariners have been doing it for
centuries. The continents of Europe and the Americas are hard to miss
if you sail due east or west on the Atlantic. But changing longitude is
a different matter, unless you have a good clock.

 

[Mxsmanic]

Hang around till nightfall -- it gets considerably easier.

It just gets darker, especially with all that overcast hiding the
moonlight.

Elementary. Follow the outermost two stars in the Big Dipper
about five times their distancefrom the top of the dipper.

All I see is clouds.

 

[Mxsmanic]

You check the altitude -- before noon the altitude increases;
after noon it decreases.

But you don't know it's noon until it changes direction, and that can
take hours.

 

[Mxsmanic]

Any chance you'd be willing to provide specific details on
what you've done in practice?

I use a simple GPS to drive around open countryside by car, at night, in
an overcast. It consistently works extremely well, and the problem of
meeting obstacles is not so great as you suppose. Even when I come
across a river, I just follow the shore until I find a bridge. The
greater the overall distance, the smaller the necessary detours tend to
become. And in many cases a GPS has showed me a more direct route to my
destination than I would have determined from a map.

 

[Mxsmanic]

Because you ask tot goddamned many stupid questions. The pilot
just got sufficiently pissed off.

Some pilots are ruled by reason rather than emotion--especially those
who manage to survive in a crisis.

Of course they're used by both civilians and that subset of
civilians known as terrorists.

If terrorists are a subset of civilians, then how can stopping GPS have
a significant crippling effect on terrorists without having the same
effect on all other civilians?

Are you going to believe the professionally prepared map or
your own two lying eyes?

I'll believe my eyes.

And after all this, I have to assume you have the integrity to
use a non-mapping GPS unit.
Correct.

We wouldn't want the device to be misled
by all those unreliable maps within.

I agree.

 

[Mxsmanic]

As in continuous, heavy, wet tree cover, where a map and
compass aren't fazed..

Wet trees should not be too much of a problem. And neither a map nor a
compass will tell you where you are.

 

[Mxsmanic]

Where do you live?

This is based on procedures for the U.S.

Where I work, people in wheelchairs are
assigned a couple or three people whose defined duty is to evacuate
the person in the wheelchair, leaving the wheelchair behind.

So they can all die together. As long as everyone else has been
evacuated, no problem. But killing half the passengers just to get a
wheelchair-bound person out of the plane is completely irrational, and
that's why it isn't done.

 

[kashe]

Why not?


It's surprising how failures actually occur in real life. Very often a
single point of failure leads to disaster, even with lots of backup
systems.


Where would the military escort go to find them?

At worst, to the source of the tramsmission.

 

[kashe]

Aviation experience shows that backup systems often don't help.

Often != always, nor even frequently.

What happens when radar breaks down? What are the backups?


Drawing upon the infinite quantity of fuel in your tanks.

Read up on how pre-flight fuel loads are calculated.

 

[kashe]

We don't know exactly how GPS would be "turned off."

We _ in particular, you_, don't know exactly how GPS would be
"turned off. So you're just pulling total catastrophe scenarios out of
your butt, with zero knowledgr of how it would be turned off and
precious little knowledgre of other relevant issues. Like how often a
map and compass fail, relative to how often GPS units fail.

Note that not remembering how a GPS unit works led one person
to call in an air strike on his own position -- not likely with map
and compass.

Note also that GPS units are capable of frequent anomalous
readings, like a person bicycling east in Scotland having his unit
suddenly showing hom heading west at 50K feet and 400mph over the
south Pacific.

 

[kashe]

The applicable regulation says that you need an update every 6.2
hours; it doesn't matter what you claim your INS will do.


Right now, that would not be a disaster.

In ten years, I expect that it would be.

And once again, it really doesn't matter what you or I think -
the possibility of the USA turning off GPS is what prompted the
EU to build Galileo. They wouldn't have decided to spend that
much money on a duplicative system if GPS were dependable.

And they should be aware that the US will do whatever is
required to make sure they can disable Galileo at the same time as
GPS. Please re-read the directive where it includes other, similar
systems.

 

[kashe]

In free countries with elected governments, the elected officials are in
fact very concerned with complaints they receive from the electorate. I
realize that this isn't the case in many of the more primitive societies
of the world.

Ask the homeless in the US. Or anyone who voted for Kerry.

 

[kashe]

I know what they are. But how can they all be "primary"?

They are each "primary" as conditions dictate.Your feet may be
primary in moving you toward an unseen object; within visual range,
your eyes become primary; within reach, to pick it up, your hand
becomes primary.

 

[kashe]

And how can all the primary colours be primary?

And how can we have primary elections in many states?

 

[kashe]

What happens if all of these stop working?

How likely is it this compared to all engines quitting at the
same time? In any case, the discussion here is about the primacy of
GPS, which would likely stop working at the same time as the rest of
your doomsday scenario. It would likely take a total loss of
electrical power, which likely entails loss of usefulness of all
control surfaces.

 

[kashe]

Each increase in traffic density over the oceans makes older navigation
methods obsolete. Once this density requires GPS accuracy, there's no
turning back the clock.

As has been stated, you decrease the density. Just out of
curiosity, what exact length of full, worldwide shutdown of GPS are
you assuming for your crackpot scenarios? One hour, day, month,
decade? If you want all of the above, you'd be better off planning how
you'll survive the catastrophe in your own house on the ground.