Clarification about the term "GPS Shutdown"

You have yet to name one.


You have yet to explain how shutting off GPS will present some
insurmountable obstacle to terrorists.


Boy, you two take the cake.

 

Where do you buy your compasses. Mine have always been reliable. You're correct
compasses can't tell you where you are. You should know where you are.

 

My Silva compass failed the very first time I used it. After trying to
make sense of the landmarks I could see and the compass readings, I
finally gave up on it and decided to exchange it later. Then I
walked around the corner and saw the entrance to the old abandoned
iron mine.

 

Which brings up the question of exactly how shutting off GPS will deter
terrorists. Precision is completely unnecessary. A missile with
inertial guidance is more than accurate enough for that. We aren't
talking about needing to put a warhead through a particular window. All
you need is to be able to target a city. Close counts in horseshoes,
nukes, and terrorist attacks. Chemical and biological weapons have even
less need for precision.

If shutting off GPS would stop an attack, then I have no objections. But
I fail to see how it would have any effect at all, other than to increase
the disruptions, making the attack even more effective.

 

There are many local anomalies in the geomagnetic field that will
introduce errors into compasses in almost any location. Just having
nearby ferromagnetic masses is enough.

What you should know won't help when you're lost.

 

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.

Tell me about the terrorist uses of GPS.

 

You can communicate with narrow beam antennas over a good portion of the
hemisphere wrt to the gound station. Dish antennas are the simplist. Bigger
dish = bigger gain = communicating lower on the horizon. Thus from Colorado
Springs most sats in the hemisphere can be updated quite quickly as seen or as
they come over the horizon.

The only reason they need to pass over any particular patch of the earth is for
position and velocity measurement using optical systems. Such stations are at
Hawaii, Ascension Island, Diego Garcia, Kwajalein, and Colorado Springs. The
SV's don't have to pass directly overhead the stations. I don't know if any of
these stations have independant means to upload messages, but it is certain that
Colorado Springs is not the only facility.

The 'monitoring' cycle to determine if the satellites are outputting a valid PR
is about 4 hours. That is used in part to set the health word for the SV. But
getting messages up to the sats takes far less time. (Another reason for
SBAS/WAAS is to get integrity data to aircraft faster than the GPS ground
segment can do it).

 

In that case, shutting off GPS would be useless in the fight against
terrorism, even though it would cripple many parts of the civilian
infrastructure. Which in turn means that GPS should never be shut off,
since doing so is always a net loss.

How would they do that, exactly?

Give a few examples.

You first. See my questions above.

I'm not the one suggesting a disabling of GPS.

Not to me. You haven't answered my questions. No amount of emotional
rhetoric ever persuades or distracts me; you _must_ answer the questions
to persuade me.

One of the things it can provoke is a crippling halt to GPS, which
seriously damages the sociey's infrastructure without any action at all
on the part of any terrorists.

Like the man said, we have nothing to fear but fear itself. And
terrorists know that very well, but most other people don't.

Guidance for _what_?

What leads you to this conclusion?

 

http://www.infoplease.com/ipa/A0005110.html

 

Well Mxsmanic, I have to say you have a good point. Missles and planes flew
well long before GPS. I think the argument in favor of a policy on shutting
down GPS in case of terrorist activity might be that GPS represents a very
low cost, very accurate means of navigation. Given that a handheld can
output a lot of meaningful data to an autopilot, it would seem that it
represents an almost perfect low cost solution to the problem of the
accurate delivery of weapons. Do I remember hearing something about one of
the 9-11 terrorists having a GPS on board the flight from Boston that turned
over my head in Albany NY and headed for the trade center. Maybe that's why
there is that concern.

But you pose a very legitimate question - why would they use GPS in the
first place? On one hand, they have good financing from their fellow
travellers around the world. There are still some weapons producers who
would like to see us damaged (or prefer money to friends). So there really
isn't much to stop then from acquiring the guidance technology they need -
providing it doesn't use our GPS system. In one of my earlier posts I
pointed out that if one wanted to detonate a dirty nuke and ruin NYC for
many years, a martyr and a pickup truck would make a great "delivery
system." Of course, that would produce a very sub-optimal ground burst with
a poor spread, but what the hell - it would terrorize NY would it not? So
there is little need to worry about GPS (or the lack thereof) as a
terrorist. Shutting it off for short periods would probably not cause any
catastrophic problems to the US, but would be a massive pain in the butt.
But it probably would just cause the terrorists to fall back to "plan B" -
the pickup truck. They are already here. They already have the explosives.
They probably have some foreign produced dirty waste to spray around. Who
needs GPS.

So why make such a policy? Well- if I were President I'd hate it if another
attack was launched against us and I hadn't crafted policies that allowed
meaningful response. Suppose, for example, Chicago was hit by a GPS guided
aircraft bomb, and some of the constant, ill-informed media critics demanded
to know what the administration had done to protect against this and the
answer was "nothing reasonable could be done to protect us from GPS guided
weapons because the civilian uses are too important." I don't think that's
politically accceptable, and that's about as legitimate a reason as any.

But your point is an excellent one - missles flew long before there was
GPS.

 

I don't think anyone with the means to develop or deploy unmanned
aircraft or cruise missiles is going to be discouraged by the cost of
other navigation systems.

I've never heard anything like this. Why not just look out the window
instead?

It was the first attack that kept him in office; I'm not sure that he's
worried about future attacks (although he can't be reelected now).

I think the President just doesn't know what he's doing, like so many
elected officials when it comes to technology.

How would you identify the bomb as GPS-guided?

 

If you have a compass and know how to use it......

 

Sam, you really nailed me on that one. Never saw it coming. Was that a GPS
enabled stealth post?

Thanks for being so patient and informative. Though a lot of fun, I think
the thread has run its course, so time for me to leave it.

My warmest regards to you Sam. I wish you all the best.

 

You certainly have an interesting 'nick' for a guy who cannot
see the disastrous consequences if the global GPS system were to
shut down for a few hours ten years from now.

And don't think it'll be shut down only in the event of an
attack - it would have to be shut down every time the threat
level goes to 'puce' or 'chartreuse'.

Terrorists generally don't phone ahead with warnings about
targeting or timing.

In short, the Bush administration comments have only confirmed
what the EU already knew when it decided to spend billions on a
duplicative and otherwise unneeded satellite constellation:

The USA simply isn't a reliable partner anymore.

 

How about airliners in flight which depend on GPS?

Granted, they all have backups now, but the USA, at least, is
already talking about shutting down the VOR/ILS system a few
years down the road.

 

I agree the threat has passed.
Also regards,
-Sam

 

On 18 Dec 2004, (Iolaos) wrote:

Snipped

A classified part of the program may well deal with the use of non civilian
(ie: military) type GPS for commercial air traffic. Nobody in this group
can say with proof positive that it is or is not being considered.

That is assuming no one here has access to highly classified national
security documents and is stupid enough to post what they have read to this
newsgroup.

 

A partnership implies shared burdens of cost and risk.

How much did and does the EU contribute to the cost of the development,
operational support, and maintenance of the US GPS such that they would be
our partners as you suggest? Did the EU bear 50% of those costs to make
them an equal partner? Do they continue to bear 50% of the operational and
maintenance costs?

If the answer is zero, then the EU was never a partner and was only reaping
a free benefit granted to them by benevolence of the US government.

If the number is somewhere in between, your dividends are based upon your
investment. In other words, you get what you pay for.

 

It still won't tell you where you are. At best, it will give you a
rough indication of north, accurate to within a few degrees.

 

Eventually the "military" GPS will be declassified, anyway.