Clarification about the term "GPS Shutdown"

[Alan Browne]

even a terrorist nuclear (nu-ku-lar) attack! The Bush
Administration needs to "get real"!

Quoting from the 2nd para of the article:
http://www.timesleader.com/mld/timesleader/news/10425933.htm

"...under only the most remarkable circumstances..." seems like a very remote
chance of it occuring.

A benefit of the White House announcement is that people, businesses and
agencies are reminded that they should not be totally dependant on GPS.

They should have a backup source of timing or navigation that allows their
function to continue at full capability and safety, or at a reduced level of
capability without compromising safety in the event of the GPS system going off
line.

This in turn means planning for it, implementing the backup or workaround, and
testing it regularly.

It is of course also interesting to see how this plays wrt Galileo and other
announcememnts discussed here about US intention to affect Galileo if desired.

Cheers,
Alan.

 

[Alan Browne]

Hans Fleischmann wrote:




And where are you going to get the keys to decrypt the p signal?

You don't need any. The Y-code is the one that needs to be decrypted to P-code.

(But your real point is valid).

Cheers,
Alan

 

[Mxsmanic]

They should have a backup source of timing or navigation that allows their
function to continue at full capability and safety, or at a reduced level of
capability without compromising safety in the event of the GPS system going off
line.

There are many things today that don't work at all without GPS. They
only exist because GPS exists. There are no backups.

 

[Alan Browne]

Clarification about the term "GPS Shutdown"

As has always been the case: "GPS Shutdown" means turning
off the C/A signal used by the civil community, but leaving
the encrypted P(Y) codes on the L1 and L2 carriers turned
on for military (and other authorized users) interrupted.

The other point I didn't mention was SCATANA. Under SCATANA, all aviation
(marine too I suppose) navigation aids are shut down (NDB, VOR, LOC/ILS, DME,
LORAN...). This is a cold war procedure (still in effect) that would help
prevent attack on North America based on using the various NAVAIDS. (In a
nutshell... the entire SCATANA plan is many pages long).

When SCATANA is issued (Class I NOTAM, eg: via radio on FSS, Enroute facilities
and terminal/tower), aircraft, with the help of ATC must seek a landing
immediately if IFR, or cancel IFR and continue DVFR if conditions permit.
(continuing VFR flight is not permitted either).

(On Sept. 11, a subset of SCATANA was invoked and elements remained in effect
for several months. NAVAIDS were not shut down).

In a today's high quality INS/GPS world, SCATANA is currently being reviewed and
revised.

The point here is that the GPS shutdown plan is little different than the
existing SCATANA system ... except of course that so many more activities beyond
air navigation depend on GPS.

Be diverse. Do not _depend_ on GPS.

If your systems or safety can be compromised by loss of GPS then plan, implement
and train for a non-GPS world. Sept. 11 happened. "NO GPS SIGNAL" can happen too.

Cheers,
Alan.

 

[Alan Browne]

Care to define "dire emergency"?

Attack by a nuclear (or other WMD) armed, unmanned aircraft (or potentially a
missile). Improbable. But so is the shutting down of GPS. So was Sept. 11
perceived as improbable.

I'd be happy to argue the merits on both sides in this forum.

As I said in my other post, the White House announcement also serves to tell
people and organizations to implement backups to GPS where warranted.

As I have said from time to time in this NG over the years, nobody should
implement anything that is totally dependant on GPS. Plan, implement, train and
regularly test for your systems working in a non GPS world.

See my other post regarding SCATANA.

Cheers,
Alan

 

[Mxsmanic]

If your systems or safety can be compromised by loss of GPS then plan, implement
and train for a non-GPS world. Sept. 11 happened. "NO GPS SIGNAL" can happen too.

So why don't air passengers have parachutes?

 

[Alan Browne]

There are many things today that don't work at all without GPS. They
only exist because GPS exists. There are no backups.

Where that is the case, then the owners/operators of such "things" should have a
contingency plan to deal with it. Whether that is at a safety level, business
level or whatever needs to be analyzed and planned for. Just saying, "if GPS
quits, we're screwed" is not enough. Even if "screwed" you still need to have a
communications plan to tell employees and customers what (if anything is
possible ) you're doing about it.

The more common problems are likely to be network communications that are
tightly tuned with GPS timing. So, what is the reduced capacity when GPS timing
is not available? Plan, implement, test, train.

Fire response teams that have integrated GPS into their procedures, should have
a fallback to voice radio procedures and maps.... Plan, implement, test, train.

And so on.

The priority is always safety. Systems that could put life or limb in jeapoardy
through failure of GPS should simply not exist.

Cheers,
Alan

 

[Juergen Nieveler]

Did anyone tell John Walker that?

Minor difference: With codes, you can decipher encrypted messages weeks
after you intercepted them and still profit from it.

With the GPS codes, it would be completely pointless unless you can
send out the codes in time to all your units in the field. The agent
stealing the codes would be pretty exposed, and would be caught pretty
fast.


Juergen Nieveler

 

[Juergen Nieveler]

From the same spy who sold you the equipment.

Must be a good spy, the keys change on a regular basis... he'd have to
steal the keys and send them out immediately, every day, and through a
covert channel that allows the recipient to receive the keys on the
same day.

Juergen Nieveler
--

AMERIKANER HABEN KULTUR???

Ja, mein Joghurt übrigens auch.
Rene Vollmeier in DTL

 

[Juergen Nieveler]

There are many things today that don't work at all without GPS. They
only exist because GPS exists. There are no backups.

Bad planning. If GPS fails, tough luck - nobody is responsible for
keeping your business running if you rely on GPS to run it.

Theoretically[0], a solar flare could kill out the whole GPS
constellation along with all the other satelites. With the
communications satelites, the companies who own them took a calculated
risk: They've got contracts with their customers, the customers loose
service and get money from the insurance company.

With GPS, there is no insurance... if your company depends solely on
GPS to work, tough luck, the landsharks^Wlawyers will have you for
lunch.

[0] Not really likely to happen, mind you, but a nice what-if
Juergen Nieveler

 

[Juergen Nieveler]

They should have a backup source of timing or navigation that allows
their function to continue at full capability and safety, or at a
reduced level of capability without compromising safety in the event
of the GPS system going off line.

At least timing won't be a problem anymore in a couple of years:
http://www.nist.gov/public_affairs/releases/miniclock.htm

Once chip-sized atomic clocks get produced in reasonable numbers,
they'll be cheap enough so that companies can have their own time
servers - in 10 years we'll probably each have our own atomic
wristwatch

It is of course also interesting to see how this plays wrt Galileo and
other announcememnts discussed here about US intention to affect
Galileo if desired.

Especially since so far Galileo seems to be planned especially for
business use, and it won't be free-to-use. If you pay for something,
you can expect a certain level of service in return. If somebody takes
pot shots at the Galileo satelites, businesses that DO rely on them
(because they had service agreements that allowed them to do so) will
get very angry, and some US lawyers will get the chance of their
lifetime: Sue the White House for damages

Juergen Nieveler

 

[Juergen Nieveler]

So why don't air passengers have parachutes?

Because bailing them out is more dangerous than doing an emergency
crash landing. Calculated risk.

The real problem is liability - if your company depends on GPS and you
don't have any contingency plans, pray that you'll never be audited by
Sarbanes-Oxley-Auditors (if your company is stocks-based, that is)...


Juergen Nieveler

 

[Alan Browne]

At least timing won't be a problem anymore in a couple of years:
http://www.nist.gov/public_affairs/releases/miniclock.htm

Once chip-sized atomic clocks get produced in reasonable numbers,
they'll be cheap enough so that companies can have their own time
servers - in 10 years we'll probably each have our own atomic
wristwatch

This came up here several months ago. And indeed it could not only help GPS'
acquire more rapidly but also eliminate the need for GPS receivers in some
applications.

It will be quite a while before this is in production.

You can buy an atomic slaved wristwatch right now for under $50.00 and they'll
throw in a travel alarm for free at the same time*. It receives its timing
signals from reference stations operated by the same people developing that
chip: http://www.boulder.nist.gov/timefreq/

You can already buy a variety of atomic time standards that are quite accurate,
many of them now have GPS built in to 'discipline' the clock.

Cheers,
Alan

*advert in SciAm Jan 2005, p.34.

 

[Ed Seedhouse]

Improbable. But so is the shutting down of GPS. So was Sept. 11
perceived as improbable.

Only by people who ignored historical facts.

Ed

 

[Johan Karl Larsen]

This is not a global shutdown they are talking about, but a regional or

even
very localized shutdown and only in very dire circumstances.

Regional/very localized shutdown! How are you going do that techwize?

 

[Alan Browne]

Alan Browne writes:




So why don't air passengers have parachutes?

Take a statement and turn it on its ear with an indirection. Your selective
editing of the preceding text is pathetic, and the snip above had little to do
with aviation ... which is highly backed up in any case.

So, why don't air pax have parachutes? Well, most air disasters happen
immediately after takeoff or just before landing. Parachutes would be of no
help, there would be no time to get them out, and likely no altitude to deploy
the chute. Statistically air travel is safer than damned near any other mode of
travel. Given the two points above parachutes would be comforting to the
ignorant and heavy, useless and expensive to all concerned.

Cheers,
Alan.

 

[John R. Copeland]

So, why don't air pax have parachutes? Well, most air disasters happen
immediately after takeoff or just before landing. Parachutes would be of no
help, there would be no time to get them out, and likely no altitude to deploy
the chute. Statistically air travel is safer than damned near any other mode of
travel. Given the two points above parachutes would be comforting to the
ignorant and heavy, useless and expensive to all concerned.

Alan.

What's really comical is to imagine the flight attendants briefing the passengers
about how to don and use a parachute.
I could just imagine that on Saturday Night Live!

 

[Mxsmanic]

Minor difference: With codes, you can decipher encrypted messages weeks
after you intercepted them and still profit from it.

Military GPS depends on codes, which are received in advance. A spy
would receive them in advance, also, and provide them to his client in
advance.

With the GPS codes, it would be completely pointless unless you can
send out the codes in time to all your units in the field. The agent
stealing the codes would be pretty exposed, and would be caught pretty
fast.

Just like John Walker was, eh?

 

[Mxsmanic]

Must be a good spy, the keys change on a regular basis ...

There are plenty of good spies, alas!

... he'd have to steal the keys and send them out immediately,
every day, and through a covert channel that allows the
recipient to receive the keys on the same day.

Yup. Perfectly possible for a good spy.

 

[Mxsmanic]

Where that is the case, then the owners/operators of such "things" should have a
contingency plan to deal with it.

You can't have a contingency plan for something that becomes impossible.
They simply go out of business.

Just saying, "if GPS quits, we're screwed" is not enough.

Why not? There are always critical points of failure.

Even if "screwed" you still need to have a
communications plan to tell employees and customers what (if anything is
possible ) you're doing about it.

Closing the doors?

The more common problems are likely to be network communications that are
tightly tuned with GPS timing. So, what is the reduced capacity when GPS timing
is not available? Plan, implement, test, train.

None of these serves any purpose if you lose a critical part of your
infrastructure.

The priority is always safety. Systems that could put life or limb in jeapoardy
through failure of GPS should simply not exist.

If the priority is safety, why is anyone discussing turning off GPS in
the first place? One can scarcely imagine anything more unsafe.