"Signal jamming a factor in future wars, general says"

jc wrote in message ...
Chad Irby wrote:

snip


Unless you spend a lot more money on them, they're also very vulnerable
to the newer EMP weapons.

In WWII the real secret weapon (proximity fuses) could only be used over
water until mid 44,in the UK with the V1 and not over enemy territory intil
the start of 45. The reason was fear of of copying a dud shell as the
allies had more to lose.

Actually, proximity fuses did not have the "self-destruct" mechanism,
therefore they would explode when hit the ground. Hence the limitation.


What is the better target for EMP weapons a GPS jammer or the NY stock
exchange?

The "piles of cheap low-power jammers" idea is nice, as long as you
don't have to keep using them.

At a rough guess the cost for a 1W jammer using cellphone components would
be ~$5, just keep sending them up with balloons (add $1).

Well, it is a bit under-estimated. I don't know much about how GPS works
(electronically), but I know it has commercial and military channels/
frequencies and commercial and military encoding. For civilian use, optimum
accuracy is receiving three GPS signals from three satellites (somebody
correct me if I am wrong, but I read it somewhere for more expensive GPS
devices for use, let's say in aviation) for elevation and position. As you
travel, the sattelites "switch" (just like GSM) control. Is it a same
frequency/coding? I don't know, but it is sure as hell that if you manage to
jam one channel, there are other two sats. Jam the other two signals, there
is one. In the meantime, your GPS receiver "struggles" to get signals from
the other two. And we are talking about civilian device.

What method are you going to use-noise or deceptive jamming? Read the
history of updates of "AN-ALQ" devices-or just one! Noise? In that case, you
are a flashbulb, and you will be attacked with alternate weapon on jamming
station. The band is narrow AFAIK, so if your opponent knows what to
"listen", you're toast.

Deceptive jamming. Well, it is not analogue signal anymore but digital and
probably encoded signal-actually, it IS encoded even for the civ use in the
matter of digital design-and probably scrambled in mil use. Thus, you have
to "doctor" the signal. Actually, signals -three satellites, remeber? You
can go to make this simmilar to tripled digital FBW system on, let's say,
F-16. Well, if you have failure on one channel then other two will feed the
aircraft with flying info, or in this instance, the weapon itself. Two of
them gone, you have one channel and two duds and you think that the flying
computer thinks that all three are duds? Wrong. Even your modem has
sufficient let-me-check-if-this-is-wright capabilities (CRC, CS) so it is
possible to imagine that FBW computer might have something simmilar. And
your jamming signal has to feed the encoded and encripted digital channel
switchig-multiple sattelite signals with false data, and it is desirable to
feed them with something meaningful to drive the weapon away, not to
owerflow it with garbage. And it's been a long time since F-16 digital FBW
was designed (I actually don't know is it possible to fly it on one channel,
but I would require it that it would! ))).

Oh, the output power. In the Battle of Britain, there was a German bombing
device called X-Gerat. Basically, you had three signals for guidance, based
on the Lorentz blind-landing system (Morse dots-too left of course,
dashes-too right of course, single tone-on course), and the offset signal to
mark the bomb dropping. Once discovered, it was jammed by the Brits by
sending "dashes". Well, it sometimes worked (and it seems it worked well!)
but there were cases that the crew was able to depict the jamming-slight but
ear-noticeable change of modulation or change of volume and to offset it.

Or back to Your cell phone-it can "sense" the distance from the GSM
station-actually, my Motorola CD920/930 has a hidden option that, when
activated can measure and display the DISTANCE from the GSM broadcast
(albait in very weird units )). Sattelites have very low output power and
if you send a "heroic" signal which is by magnitude stronger then satellite
signal, the system might think "this is too powerful", or "this is too
close" and simpy switch to something else. Remember, expirienced LW pilots
were able to depict the false signals. And code-breaking is not a trivial
thing; put a password to a MS-Word-file that is, let's say 5 characters long
and try to crack it with some program designed to do it, let's say Advanced
Office Password Recovery. Yeah, it will eventually break it, but count how
long it will take!

Also, You have A GPS and GLONASS (a Soviet GPS); while GLONASS is reportedly
in a bad shape, as far as I can remember India (I am really not sure!) uses
BOTH systems which might suggest that it is not in such bad shape after all.
While I am not aware of Russian GPS bombing/missile systems in use, some of
their (export?) weapon systems use both.

I agree that we are talking about the weapon (figter, bomber, cruise missile
or JDAM) that might not have all the "offset" capabilities that I have
mentioned here; I might not even be correct in numerous things. Actually,
you will need a (really, really) good sample either of the good portion of
the knowledge how -military- part of the system works or the system itself.
And once you develop a system, it will certainly not be of the cell-phone
size but rather of an underwing or wingtip pod size, weight and cost.

Nele

NULLA ROSA SINE SPINA