Sectional use

On Jan 28, 10:55 pm, Newps wrote:
Mxsmanic wrote:
And then the bad guys will head to the area of a major airport, turn
on the GPS jammer, and kill a few thousand people in an hour without
anyone even knowing they were there.
Do whatever you want to a GPS signal any time, anywhere. Not one person
would die as a result.

That's an odd conjecture to make, considering how many even in this
thread have mentioned how much some pilots rely on GPS in instrument
conditions. It's not hard to imagine a fair number of dark / cloudy
accidents in mountainous areas if a GPS signal was mucked with..
either by changing the "altitude" or even just "moving" the plane over
a mile or so.

Kev

In article om,
"Kev" wrote:

Do whatever you want to a GPS signal any time, anywhere. Not one person
would die as a result.

That's an odd conjecture to make, considering how many even in this
thread have mentioned how much some pilots rely on GPS in instrument
conditions.

If people are using a GPS without RAIM or FDE then I guess using a VFR GPS
in IMC as primary without crosscheck could be a problem when exposed to
spoofing. But there the problem isn't the spoofing, the problem is not using
proper navigation equipment for the type of flight.



It's not hard to imagine a fair number of dark / cloudy
accidents in mountainous areas if a GPS signal was mucked with..
either by changing the "altitude" or even just "moving" the plane over
a mile or so.

How do you change the altitude or location of GPS and not have
RAIM or FDE alarm?

--
Bob Noel
Looking for a sig the
lawyers will hate

On Jan 29, 6:29 am, Bob Noel
wrote:
In article om,

"Kev" wrote:
It's not hard to imagine a fair number of dark / cloudy
accidents in mountainous areas if a GPS signal was mucked with..
either by changing the "altitude" or even just "moving" the plane over
a mile or so.
How do you change the altitude or location of GPS and not have
RAIM or FDE alarm?

For purposes of this speculation, by spoofing the satellite signals.
A GPS receiver's RAIM algorithms wouldn't know any difference as long
as the signals came with "correct" data.

It's not much different than the "evil twin" method of spoofing a
Starbuck's WiFi hotspot, and then capturing everyone's keystrokes as
they log into their bank account. That is, you simply provide a
stronger signal.

Granted, it seems like a lot of work just to try to down a few GA
planes in a small hilly area. Airliners don't use GPS that much, if
at all. So it's not worth the trouble.

Personally, I'm more worried that terrorists are renting homes near
airports, and one day they'll all pop up at the same time with a
shoulder-fired missile. You can just imagine the government deciding
to raze all houses for miles around major airports.

Regards, Kev

"Kev" wrote

For purposes of this speculation, by spoofing the satellite signals.
A GPS receiver's RAIM algorithms wouldn't know any difference as long
as the signals came with "correct" data.

It's not much different than the "evil twin" method of spoofing a
Starbuck's WiFi hotspot, and then capturing everyone's keystrokes as
they log into their bank account. That is, you simply provide a
stronger signal.

It isn't that simple because the receiver would still be getting information
from the satellite. The combined information would be a mess that would
cause the GPS to ignore that portion of the signal.

Pulling this off, if it could even be done, would be extremely difficult and
expensive - that's what makes it impractical. Beyond that, I seriously
doubt that anyone would fly their airplane into the ground as a result.

BDS

On Jan 29, 10:13 am, "BDS" wrote:
"Kev" wrote

For purposes of this speculation, by spoofing the satellite signals.
A GPS receiver's RAIM algorithms wouldn't know any difference as long
as the signals came with "correct" data.

.It isn't that simple because the receiver would still be getting information
from the satellite. The combined information would be a mess that would
cause the GPS to ignore that portion of the signal.

No sir, it would only be getting information from the spoofer. Since
the signal from space is far less than a billionth of a watt, it's
very easy to override the sat signals. I worked in Electronic
Warfare for several years, and we spoofed many kinds of signals.
Civilian GPS is not complex.

Pulling this off, if it could even be done, would be extremely difficult and
expensive - that's what makes it impractical.

No sir, it's easy. Satellite GPS simulators are available off-the-
shelf, for testing and development. That's all you need. For that
matter, civilian GPS receivers are probably dumb enough to let you
record a set of signals at one point on the globe, then broadcast them
back later somewhere else.

You don't have to believe me, google up gps spoofing, find stuff like:

http://pearl1.lanl.gov/external/c-adi/seals/spoof.shtml

Beyond that, I seriously
doubt that anyone would fly their airplane into the ground as a result.

Flying at night. Terrain or structures around. Sure, why not? But
again, it's not worth the few GA results.

Kev

Kev writes:

Flying at night. Terrain or structures around. Sure, why not? But
again, it's not worth the few GA results.

Why would anyone use it against GA? Logically they'd use it near a
major airport, and crash the commercial airliners.

--
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BDS writes:

It isn't that simple because the receiver would still be getting information
from the satellite.

Yes, it is that simple. That's why the military took measures against
spoofing long ago (essentially, they resorted to encryption, but that
isn't practical for civilian use).

The combined information would be a mess that would cause the GPS to
ignore that portion of the signal.

That's not how GPS works. It's not like drowning out one AM radio
station with another.

Pulling this off, if it could even be done, would be extremely difficult and
expensive - that's what makes it impractical.

Unfortunately, it is quite easy, and military and government
organizations can already do it as required. It's a pretty good bet
that the same equipment has fallen into the wrong hands by now.

Beyond that, I seriously
doubt that anyone would fly their airplane into the ground as a result.

If someone moves an ILS to a mountainside in zero visibility, where
will the Cat IIIc landings occur?

--
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"Mxsmanic" wrote

Beyond that, I seriously
doubt that anyone would fly their airplane into the ground as a result.

If someone moves an ILS to a mountainside in zero visibility, where
will the Cat IIIc landings occur?

GPS is not part of the ILS system.

This all sounds good from a movie perspective but it wouldn't be so easy to
do in real life, and the outcome would probably be less than newsworthy.

I am more worried about large trucks and what they can carry and where they
can deliver it.

BDS

BDS writes:

GPS is not part of the ILS system.

I know that. Obviously I am not making my point.

This all sounds good from a movie perspective but it wouldn't be so easy to
do in real life, and the outcome would probably be less than newsworthy.

Jet aircraft hitting the WTC towers at high speed and exploding in
mushroom clouds of flame sounded good from a movie perspective, too,
until it actually happened.

I am more worried about large trucks and what they can carry and where they
can deliver it.

Terrorists concentrate on the spectacular, not on the destructive.
The idea is to maximum shock value and media appeal. The actual level
of destruction is far less important. Terrorists want their
adversaries to become frightened and irrational (and thus easily
manipulated). They don't actually care about the targets.

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Kev writes:

Airliners don't use GPS that much, if at all.

You're sure? What about Flight Management Systems? And what about
the ever-increasing number of GPS-based approaches?

Personally, I'm more worried that terrorists are renting homes near
airports, and one day they'll all pop up at the same time with a
shoulder-fired missile. You can just imagine the government deciding
to raze all houses for miles around major airports.

That is also a tremendous problem, and probably appeals a lot more to
terrorists because of its media appeal. Exploding aircraft are much
more photogenic than crashing aircraft.

--
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