Clarification about the term "GPS Shutdown"

They won't know either - Pentagon won't tell them

It's not as easy as you might think. The spy will have to get the
information out. If he wants to avoid being caught, he has to make sure
that he doesn't always rush out immediately after receiving the new
codes - that might draw suspicion. He'll also wants to drop the codes
off in a secure place, where they get retrieved hours later by somebody
"just strolling along", who'll also try not to go there every day at
the same time.

The legitimate users can get their keys at the same time every day
without drawing suspicion - they've got a big advantage.


Juergen Nieveler

 

Now you contradict yourself. If "each satellite covers an entire
hemisphere", each satellite also can be seen by anybody in that
hemisphere, and thus each satelite can be reprogrammed by an antenna in
that hemisphere. Pentagon has access to ground stations around the
world (CONUS, Europe, Australia), so it would be trivial for them to
reprogramm the satellites - they don't have to pass a single point on
earth for this.

This is your wakeup call, then. Don't depend on GPS, it might not
always be available.


Juergen Nieveler

 

Finally I hear a fresh voice of reason. Despite what others may think, if I
lose GPS, I will not pilot my craft into the side of a mountain. Nor will I
lose the ability to land safely. There is nothing in the forseeable future
to make me think otherwise.

This whole topic has become nothing more than a "straw dog" based more on
politics than reality.

I have yet to see a company or business named that requires the use of GPS
signals to keep their clocks synchronized to within nanoseconds. Hell, my
cell phone time is synchronized with the cellular provider and the last
time I checked (1 minute ago) it is a full 2 minutes off. Anyone else using
Cingular? Check it yourself.

I have seen no convincing evidence that the selective shutting down of the
GPS signals will have a dire effect on any major business. If such a
business exists, please state the company name here so that I can be sure
it is not in my stock portfolio. I would not invest in a company that has
such poor management that a back up plan is not in place.

I well remeber the dire predictions of the year 2000. Books were written,
people panicked and stocked up with food and supplies, gun sales went up,
and on and on. Huge profits were made by the purveyors of gloom and doom.
Shall we now start a new frenzy?

So the EU will begin their own program which is equivalent to the US GPS
system. God Bless them. Nothing wrong with that. Let's hope that our
European friends that use GPS for a hobby are not forced to pay a heavy
usage tax for the privelege of using the new system. I don't think that the
casual hobbyist geocacher, jogger, cycler, or automobile user will be
willing to pay the potentially heavy cost just to avoid the remote
possibility that the US system is off for a period. Of course, there is the
real possibility that receivers of the US GPS signals could be outlawed in
those countries thereby forcing them to "pay to play".

Is one so naive as to believe that our nations governments are so far apart
that we would not be in close collaboration if the systems were to be used
by an enemy of any State or Nation? Do you believe that the US would not
shut down their GPS system if there was knowledge it was going to be used
in a terror attack in another State or Nation? Do you believe the opposite
would be true?

Quite frankly, the plan as outlined by the Federal government promises
improvements to the existing GPS. That is to be welcomed. I have yet to see
anything rationally presented where there would be a dire national
emergency if it were selectively shut down for a period of time.

Hint, give me the Company names that are so dependant on GPS timing or
navigational ability that they would cease to function if the GPS signals
were shut down for some period so that I can divest them from my portfolio.

As I said, this whole thing is a "straw dog", politically motivated, and
would not be worthy of serious discussion except for the technical
knowledge being shared.

 

Finally I hear a fresh voice of reason. Despite what others may think, if I
lose GPS, I will not pilot my craft into the side of a mountain. Nor will I
lose the ability to land safely. There is nothing in the forseeable future
to make me think otherwise.

This whole topic has become nothing more than a "straw dog" based more on
politics than reality.

I have yet to see a company or business named that requires the use of GPS
signals to keep their clocks synchronized to within nanoseconds. Hell, my
cell phone time is synchronized with the cellular provider and the last
time I checked (1 minute ago) it is a full 2 minutes off. Anyone else using
Cingular? Check it yourself.

I have seen no convincing evidence that the selective shutting down of the
GPS signals will have a dire effect on any major business. If such a
business exists, please state the company name here so that I can be sure
it is not in my stock portfolio. I would not invest in a company that has
such poor management that a back up plan is not in place.

I well remeber the dire predictions of the year 2000. Books were written,
people panicked and stocked up with food and supplies, gun sales went up,
and on and on. Huge profits were made by the purveyors of gloom and doom.
Shall we now start a new frenzy?

So the EU will begin their own program which is equivalent to the US GPS
system. God Bless them. Nothing wrong with that. Let's hope that our
European friends that use GPS for a hobby are not forced to pay a heavy
usage tax for the privelege of using the new system. I don't think that the
casual hobbyist geocacher, jogger, cycler, or automobile user will be
willing to pay the potentially heavy cost just to avoid the remote
possibility that the US system is off for a period. Of course, there is the
real possibility that receivers of the US GPS signals could be outlawed in
those countries thereby forcing them to "pay to play".

Is one so naive as to believe that our nations governments are so far apart
that we would not be in close collaboration if the systems were to be used
by an enemy of any State or Nation? Do you believe that the US would not
shut down their GPS system if there was knowledge it was going to be used
in a terror attack in another State or Nation? Do you believe the opposite
would be true?

Quite frankly, the plan as outlined by the Federal government promises
improvements to the existing GPS. That is to be welcomed. I have yet to see
anything rationally presented where there would be a dire national
emergency if it were selectively shut down for a period of time.

Hint, give me the Company names that are so dependant on GPS timing or
navigational ability that they would cease to function if the GPS signals
were shut down for some period so that I can divest them from my portfolio.

As I said, this whole thing is a "straw dog", politically motivated, and
would not be worthy of serious discussion except for the technical
knowledge being shared.

 

Finally I hear a fresh voice of reason. Despite what others may think, if I
lose GPS, I will not pilot my craft into the side of a mountain. Nor will I
lose the ability to land safely. There is nothing in the forseeable future
to make me think otherwise.

This whole topic has become nothing more than a "straw dog" based more on
politics than reality.

I have yet to see a company or business named that requires the use of GPS
signals to keep their clocks synchronized to within nanoseconds. Hell, my
cell phone time is synchronized with the cellular provider and the last
time I checked (1 minute ago) it is a full 2 minutes off. Anyone else using
Cingular? Check it yourself.

I have seen no convincing evidence that the selective shutting down of the
GPS signals will have a dire effect on any major business. If such a
business exists, please state the company name here so that I can be sure
it is not in my stock portfolio. I would not invest in a company that has
such poor management that a back up plan is not in place.

I well remeber the dire predictions of the year 2000. Books were written,
people panicked and stocked up with food and supplies, gun sales went up,
and on and on. Huge profits were made by the purveyors of gloom and doom.
Shall we now start a new frenzy?

So the EU will begin their own program which is equivalent to the US GPS
system. God Bless them. Nothing wrong with that. Let's hope that our
European friends that use GPS for a hobby are not forced to pay a heavy
usage tax for the privelege of using the new system. I don't think that the
casual hobbyist geocacher, jogger, cycler, or automobile user will be
willing to pay the potentially heavy cost just to avoid the remote
possibility that the US system is off for a period. Of course, there is the
real possibility that receivers of the US GPS signals could be outlawed in
those countries thereby forcing them to "pay to play".

Is one so naive as to believe that our nations governments are so far apart
that we would not be in close collaboration if the systems were to be used
by an enemy of any State or Nation? Do you believe that the US would not
shut down their GPS system if there was knowledge it was going to be used
in a terror attack in another State or Nation? Do you believe the opposite
would be true?

Quite frankly, the plan as outlined by the Federal government promises
improvements to the existing GPS. That is to be welcomed. I have yet to see
anything rationally presented where there would be a dire national
emergency if it were selectively shut down for a period of time.

Hint, give me the Company names that are so dependant on GPS timing or
navigational ability that they would cease to function if the GPS signals
were shut down for some period so that I can divest them from my portfolio.

As I said, this whole thing is a "straw dog", politically motivated, and
would not be worthy of serious discussion except for the technical
knowledge being shared.

 

SNIP

Right! Always carry a compass.

 

Each satellite covers almost a whole hemisphere, but each satellite has
a different footprint. As long as no more than 2 active satellites are
visible over the horizon, GPS is useless in that particular area. 100
miles away the horizon will be different, and there might be more
active satellites visible.


Juergen Nieveler

 

Not really likely. You'd want to keep equipment as simple as possible -
being able to administer them remotely means that you have to have
2-way communications for every military GPS receiver. Might be doable
for the IVIS systems, but impossible for the handheld gear.

And it's not as if loosing a military GPS receiver would be that
critical, anyway: Given a 24 hour code cycle, the lost receiver would
remain usefull for 24 hours at the most. That's not really much - you
can't just say "Oh, I'll capture a receiver and stage a
counter-offensive within the next few hours using it". And you won't be
able to retrieve the codes from the receiver and enter them into your
missile guidance system, because such systems will be made tamper-proof
- as soon as you turn them off to dismantle them, they'll loose the
keys and are turned into junk.


Juergen Nieveler

 

No surprise, really - but I'm sure that they don't send the codes out
weeks in advance, and I'm willing to bet that it's closer to 24 hours
in advance... precisely for the reason I keep stating: To make it more
difficult for a spy to send out the codes in time to be usefull.


Juergen Nieveler

 

What makes you think so?

 

precision agriculture on a global scale
precision guided ordinance
precision mapping of utility poles, oil wells
tracking of wildlife
automobile navigation systems

more: http://www.google.com/search?q="requiring+GPS"

 

You're too polarized in your thinking and you haven't named a single thing that
is so GPS dependant that it will fail totally. It is acceptable, for example,
in a communications network that its capacity (datarate) falls in the event of a
component failure. There is no excuse for it to fail entirely.

The point, which you are slipping and sliding to avoid recognition, is that you
should not design anything that is susceptible to a single point failure where
safety is involved.

 

Turn off all the satellites that a GPS receiver can see and then
calculate the numbers seen at all point on the earth and the DOPs
at those locations and you will find that the damage is not nearly
as *localized* as you might think. Do the calculations.

 

precision agriculture on a global scale
precision guided ordinance
precision mapping of utility poles, oil wells
tracking of wildlife
automobile navigation systems

more: http://www.google.com/search?q="requiring+GPS"

 

precision agriculture on a global scale
precision guided ordinance
precision mapping of utility poles, oil wells
tracking of wildlife
automobile navigation systems

more: http://www.google.com/search?q="requiring+GPS"

 

They won't. Even if they did, keys are valid for 7 days. If the next 8 weeks
worth of keys were stolen, then they would be re-issued. Control of these keys
is extremely tight. No less tight than other COMSEC material.

A very few businesses may be severely afected. Many partially affected. Most,
not affected at all. The economy will not come crashing down as many expect.
Last summer's NE power failure was huge economically but life and business go
on. A GPS outtage of 24 hours would have far less impact.

He better do it within whatever time remains for the keys in that receiver which
would be no more than 7 to 14 days.

Right on. Further, I beleive that most systems employing GPS have adequate
capability to work without GPS for periods ranging from minutes to weeks to
years. The designer/operators of those systems must make sure they know the
limitations whan GPS is not available and that the system can indeed work.
Planning, implementing, testing and training are always required.

Very well put.

Cheers,
Alan

 

In a lifeboat? On an airplane? On horseback?

 

It won't happen that way. Do't worry about it. If terrorists (or a warring
nation) use GPS, it will be C/A.

No. The satellite nav packages keep on running. From block II (or is it IIR),
the satellites have to maintain spec. accuracy without updates for 30 (or is it
60) days. So if you shut off the transmitter, the nav keeps on going. The
Alamanc data in your receiver is good (by design) for 30 days, but in reality is
sufficient for much longer to aid acquisition.

Even the older sats, if they stopped transmitting, wouldn't have moved so far
from their orbital paths that their unupdated ephemeris would be totally
unuasable after many days. An unnoticeable degree of degradation for almost all
receivers except surveyors and the people who update GPS. And that would be
resolved within days after return to service.

In a heartbeat.

No aircraft depends (legally) on GPS alone for navigation. VOR's, LORAN-C,
NDB's, etc. are still doing fine, and if you have INS you don't really care at all.

You have yet to name one.

You do shut off gas. If it was usuggested that shutting off GPS would prevent
another Sept. 11 type disaster, I don't think there would be more than a minutes
hesitation. You don't really need to shut it off, you just need to skew the C/A
(via S/A) so badly that no receiver would generate a valid solution. After the
emergeny, normal reception would be available in about 4 hours.

In the case that an attack was taking place on the US, most sats helping a
receiver in the US could be imediately commanded to have a huge S/A skew making
receivers come up with unusable solutions.

 

I don't think that there is a proposal out there that reasonably anticipates
shutting down civilian GPS for months. About the only thing on the list
that requires immediate GPS support is precision guided ordinance, and I'm
guessing the military isn't depending on the civilian signals for this one
anyway.

I am somewhat familiar with "precision agriculture", and frankly some of it
is a tractor salesmans best tool for maintaining margin. A year without it
would not substantially impact the world's food supply.

All the wildlife would be happy to avoid those annoying wildlife
biologists - in fact the cancellation of wildlife studies could result in
more federal dollars for reading programs or midnight basketball or
something really important like health care for the elderly.

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.

In short, there's nothing on this list that would be substantially impacted
by a short pause in GPS signals. As the minutes turn into hours or weeks or
months, the impacts might become measurable.

 

When you start adding up the man-hours of productivity lost, potential lives
lost, data lost, equipment and networks lost... this could easily be higher
than billions of dollars (US) per day! This is really an economic issue.