Clarification about the term "GPS Shutdown"

[Alan Browne]

Well, I don't think anyone suggested it will. However, if you think a lot of
money won't be lost, then you are incorrect.

I don't even think that a lot of money will be lost. There will be a scramble
of sorts to establish workarounds, and there will be delays, and yes, time is
money ... but it won't be for any individual, company or agency that disastrous.
And any person, company or agency that has integrated GPS into their
operations to the point where it is perceived as a serious risk should have a
plan in place to deal with it. A risk assessment would likely place the risk as
very low or extremely low, so only if loss of GPS would have a very strong
impact would an investment in backups and workarounds be worthwhile.

Cheers,
Alan.

 

[Mxsmanic]

I don't even think that a lot of money will be lost. There will be a scramble
of sorts to establish workarounds, and there will be delays, and yes, time is
money ... but it won't be for any individual, company or agency that disastrous.

This is logically equivalent to saying that GPS serves no useful
purpose, which is manifestly untrue.

And any person, company or agency that has integrated GPS into their
operations to the point where it is perceived as a serious risk should have a
plan in place to deal with it.

For many applications, there are no alternatives to GPS, and thus no
plan to "deal with" an outage is possible. That's rather like saying
that an airline should have a plan for operating without jet fuel.

A risk assessment would likely place the risk as
very low or extremely low, so only if loss of GPS would have a very strong
impact would an investment in backups and workarounds be worthwhile.

The greater the impact of a GPS outage in a specific domain, the more
likely that there is no workaround for that outage.

 

[Dave Baker]

And any person, company or agency that has integrated GPS into their
operations to the point where it is perceived as a serious risk should have a
plan in place to deal with it.

Well, I can probably name 10 or so companies without even thinking very hard
where this is not the case, including our own.

If you can suggest an alternative to GPS then I'm all ears though.

Dave

The email address used for sending these postings is not valid.
All replies to the group please.

 

[Alan Browne]

Alan Browne writes:




This is logically equivalent to saying that GPS serves no useful
purpose, which is manifestly untrue.

GPS serves many wonderful purposes. That is not an excuse to make one, a
business, an agency or anything dependant upon them. And few are. You've
mentioned communications as beging dependant. They're not. GPS just makes it
easier, cheaper and faster. Fall back is less easy, more expensive OR slower.

For many applications, there are no alternatives to GPS, and thus no
plan to "deal with" an outage is possible. That's rather like saying
that an airline should have a plan for operating without jet fuel.

You have yet to name a single thing that cannot function (and I'll genrerously
allow degraded modes) without GPS being available.

There a million things that can't operate without fuel. There is little that
can't operate without GPS.

The greater the impact of a GPS outage in a specific domain, the more
likely that there is no workaround for that outage.

There is (as I've stated several times) no excuse to make anything so dependant
on GPS that its absence constitutes a hazard to people's safety or valuable
commodities.

And I remind you (again) that you've failed to mention a single thing that would
collapse completely from lack of GPS service. And that's for a very good
reason: there is nothing that will completely collapse from lack of GPS service.
It may make things easier, cheaper, faster or whatever, but it is not essential.

 

[Alan Browne]

Well, I can probably name 10 or so companies without even thinking very hard
where this is not the case, including our own.

Name three or more and why they are 100% dependant on GPS. That is to say in
the absence of GPS there is no plausible workaround.

Risk management is a serious issue to many stockholders. If the absence of GPS
is perceived as no-chance-in-hell and the stockholders accept that, then that is
fine. If the risk is perceived as possible and the impact on the company is
serious, then stockholder will want a risk management plan.

If it happens, will your company suffer a loss? How big is the loss? Can your
company function without GPS for 24 hours? 72 hours? A week? A month... What
workarounds would you invoke in the absence of GPS for those periods? If the
consequence is little, then it's hardly worth a plan, but the if consequence is
important then the workarounds require communication, resources, etc. then a
plan is required and it needs to be communicated.

If you can suggest an alternative to GPS then I'm all ears though.

How do you use GPS? That would indicate the alternative. Bearing in mind that
the alternative can (and will be) be less performing than GPS in one or many
ways... but will allow the company or agency to function.

Cheers,
Alan

 

[Alan Browne]

Because ship owners like to know where their assets are.

Especially when they are not where they are supposed to be.

A ship's crew can navigate without GPS. Although now that Omega is gone, it's
just more work. When near coasts, they can fix their position very handilly
with shore beacons. When in mid-ocean a simple estimate based on heading, speed
and time can be made or a sextant can be used. There is no need to be as
accurate as GPS for what you describe above. Piracy/theft are special cases.

Cheers,
Alan.

 

[Alan Browne]

nowadays...

A gyroscopic compass has no concept of either true or magnetic
north.

Most multiengine aircraft over 5000 lbs or so carry a gyromagnetic compass (or
two). In this a 'flux valve' drives an alignment signal to the gyro and the
gyro is continuously corrected to point at magnetic north.

More recent 'gyro systems' such as fibre-optic gyro AHRS (attitude heading
reference system) also use a flux valve input to keep the gyro aligned with the
magentic north. The flux valves are typically locates in the tail or the
wingtips to reduce the influence of ferrous metals (some engine parts) and
electrical currents.

It simply stays pointed in the direction to which you set it.

No, it precesses due to friction unless corrected by the pilot (using a
'whiskey' compass) or by signals from the flux valve if so equipped. Attitude
gyros also have long period erection systems such that their spin axis is always
pointed to the center of the earth regardless of movement around the
circumfrence. (The 'correction rate is very slow of course so it won't correct
perceptibly during normal manouevers.)

The only place that a magnetic compass is not usable is in regions approaching
the north magnetic pole. As the magnetic lines of force 'tilt' to near vertical
as the comapass approaches the pole, the magnetic compass gyrates wildly and
cannot be used (the signal from a flux valve is likewise eratic). In these
regions pilots navigate in Grid North orientation but must be mindful of the
gyro precession and re-align the compass from time to time using landmarks and
radio nav aids.

Cheers,
Alan.

 

[Alan Browne]

A gyroscopic compass doesn't show you the magnetic north, it shows
true north. Airplanes tend to carry at least one of those nowadays...

See my reply to Fafnir ...

 

[Alan Browne]

Mark McIntyre writes:




It's a problem for the military, whence the motivation for GPS.

The military 'motivation' for GPS has little to do with being dropped in the
middle of nowhere.

 

[Mxsmanic]

The military 'motivation' for GPS has little to do with being dropped in the
middle of nowhere.

The military discovered long ago that one need not be dropped in the
middle of nowhere in order to get lost.

 

[Mxsmanic]

GPS serves many wonderful purposes. That is not an excuse to make one, a
business, an agency or anything dependant upon them.

Many of the wonderful purposes served by GPS are applications that were
impossible before GPS existed. Organizations that depend on these
applications are necessarily dependent on GPS; they cannot be otherwise.
Suggesting that they somehow find a way to do without something that
cannot be done without is illogical.

You've
mentioned communications as beging dependant. They're not. GPS just makes it
easier, cheaper and faster.

If ease, cheapness, or speed are of the essence of the communications
application, then the application is dependent on GPS, and there can be
no backup.

You have yet to name a single thing that cannot function (and I'll genrerously
allow degraded modes) without GPS being available.

GPS navigation.

You have yet to describe a single action carried out by terrorists that
would be definitively prevented by shutting off GPS. And the burden of
proof is upon you.

There a million things that can't operate without fuel. There is little that
can't operate without GPS.

There is little that can't operate without the beating of your heart.

There is (as I've stated several times) no excuse to make anything so dependant
on GPS that its absence constitutes a hazard to people's safety or valuable
commodities.

There are many, many things in this world that are entirely dependent on
single, irreplaceable technologies, including GPS. Suggesting that
anyone do without them simply because of these critical dependencies is
irrational.

Everything is a question of risk assessment and management, and
cost-effectiveness. It is not rational to shut down GPS out of any
terrorist act, much less out of paranoia or hysteria. The potential
gain is eclipsed by the certain loss.

And I remind you (again) that you've failed to mention a single thing that would
collapse completely from lack of GPS service. And that's for a very good
reason: there is nothing that will completely collapse from lack of GPS service.

Including terrorist actions. So why turn GPS off?

Remember, the same rules that apply to other uses of GPS also apply to
terrorist uses. You cannot have your cake and eat it, too.

It may make things easier, cheaper, faster or whatever, but it is not essential.

Sometimes making something easier, cheaper, or faster is of the essence
itself.

 

[Mxsmanic]

A ship's crew can navigate without GPS.

I suspect that the problem is not them getting lost, but them going to
places where they should not be.

 

[Alan Browne]

Alan Browne writes:




The military discovered long ago that one need not be dropped in the
middle of nowhere in order to get lost.

//sigh// more crap from Mx.// I explained to you in another post the motivation
for the US mil GPS development beyond the mere problem of knowing where one is.

 

[Alan Browne]

Mxsmanic wrote:


You've managed to regurigitate everything that you've already erroneously stated
and that I and others have pointed out to you as being mis-informed, incomplete
and plain wrong.

You've still to name a single thing that will be so affected by GPS as to fail
to have an adequate workaround. Several people, and I, have pointed out ways in
which terrorists could use GPS for harmful purposes.

There is little, if anything, that is 100% dependant on GPS to the point where
there is no adequate workaround.

 

[Alan Browne]

Alan Browne writes:




I suspect that the problem is not them getting lost, but them going to
places where they should not be.

They can do that with or without GPS. And don't turn this into a "so can the
terrorists". There is a difference between cheap and easy v. expensive and
difficult.

 

[H.W. Stockman]

Many of the wonderful purposes served by GPS are applications that were
impossible before GPS existed.

Could you name those applications, and explain why they could not be done
without GPS? Are they critical applications?

 

[Mxsmanic]

Could you name those applications, and explain why they could not be done
without GPS? Are they critical applications?

Could you name the things for which terrorists must depend on GPS, and
explain how shutting down GPS would prevent them from continuing to do
those things?

 

[Mxsmanic]

They can do that with or without GPS.

Yes, but with GPS, the ship's owner will know about it, so they may be
more reluctant, or more careful.

And don't turn this into a "so can the
terrorists". There is a difference between cheap and easy v. expensive and
difficult.

There is no other way to do this without GPS. There are other, similar
applications as well; it isn't useful just for ships.

 

[Juergen Nieveler]

Many of the wonderful purposes served by GPS are applications that
were impossible before GPS existed.

Name one.

GPS navigation.

Just because you don't know how to navigate with a map and compass
doesn't mean that navigation is impossible without GPS.

Juergen Nieveler

 

[Juergen Nieveler]

Yes, but with GPS, the ship's owner will know about it, so they may be
more reluctant, or more careful.

Just HOW will the ship owner know anything? GPS is strictly one-way,
you can't check the position of a ship without having somebody on the
ship cooperating with you.


Juergen Nieveler