Stryker/C-130 Pics

(phil hunt) wrote in message ...
On Mon, 22 Sep 2003 20:07:59 -0400, Paul Austin wrote:

"phil hunt" wrote in message
...
On Sun, 21 Sep 2003 14:06:30 -0400, Paul Austin

So what data rate will FCS run at? Consider a unit such as a Brigade
- will the data links be radio, or something else (laser beams?
fiber optic? ethernet?) or a mixture?

The first Brigade XXI exercises were run using 64Kbps links over HF
radios. Not suprisingly, trials proved that slow a data fabric
completely inadequate.

Presumably because all the nodes were trying to talk at the same
time. What if there were fewer nodes on the network, say 200 instead
of 1000?

There are advantages to HF links but VHF, UHF
and higher frequencies will be used. The Navy is planning EHF links.

Higher frequencies mean more banfdwidth, I assume. What are the
advantages of lower frequencies - range?

Iv wonder if there are any plans to civilianise this technology; it
might complement WiFi quite well.

Comms equipment is giving out radio signals; if these can be
pinpointed and targeted, the unit is ****ed. Imagine a swarm of
cheap cruise missiles[1] homing in on radio signals from the nodes
on the tactical internet.

Not nearly as easy as it seems, since everything is spread spectrum,
fast hopping and anti-jam.

The signal must be such that the extended receiver can hear it. So
others can too, in principle. (Though detecting the signal and
knowing where it's from aren't the same thing). I'm not a radio
engineer but I can imagine a few ways how direction-finding might
work; for example place two (or 3) detectors a few meters apart
and calculate the time delay between each one receiving the signal.

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*, over a
pretty wide band of freq's (this is why synchronization of the radios
on a time basis is critical to succesful operation of the net). It is
hard enough for the average "rest of the world" intel unit to DF an
old fashioned non-hopping transmitter if the radio operator uses good
RTO procedures--trying to pluck enough of these random
fractional-second bursts out of the ether to determine a direction is
more difficult by a few orders of magnitude.


If your comms are degraded badly enough, you'll lose whether you
have light forces or tanks; even the best MBTs don't have perfect
protection against ATGMs, etc.

MBTs are nearly immune to ATGMs now. About the best that can be hoped
for by man-portable systems is a mobility kill.

Oh? I was under the impression the Russian Kornet was pretty good.

Heavier ATGMs have
some hope of doing more than blowing a track but not along the frontal
arc.

ATGMs don't have to hit the front; they could be designed to hit the
top, for example. And making the warhead bigger is not a problem to
do, if the missile vis carried by a vehicle.

The fact that most anti-armor development programs seem to be headed
in the kinetic penetrator direction seems to support the idea that the
chemical energy approach is waning.

Brooks


Does this work? It sounds nice, but I'm not sure if it's practical.
What if the capacitors short out? That would release large amounts
of enery, if it's enough to melt a solid piece of metal.

Success is a matter of sufficient development I find the notion of
melting a 10-20mm thick rod of refractory metal in microseconds
literally incredible.

I'm a bit dubious too.

(I'm not an electronic engineer, so I've cross-posted this to some
newsgroups which might be able to give informed comment on a number
of points.)

On 23 Sep 2003 05:51:41 -0700, Kevin Brooks wrote:
(phil hunt) wrote in message ...
[regarding battlefield internet]
The signal must be such that the extended receiver can hear it. So
others can too, in principle. (Though detecting the signal and
knowing where it's from aren't the same thing). I'm not a radio
engineer but I can imagine a few ways how direction-finding might
work; for example place two (or 3) detectors a few meters apart
and calculate the time delay between each one receiving the signal.

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

over a
pretty wide band of freq's (this is why synchronization of the radios
on a time basis is critical to succesful operation of the net).

So the frequency changes are pre-determined on a time basis?

If there is a radio receiver, is it better able to detect/deceive a
signal whgen it knows the frequency in advance? Or can it "sniff"
for lots of frequencies at a time and pick out what looks
interesting?

If two receivers, placed say 10 m aparet, both pick up a signal, how
accurately can the time difference between the repetion of both
signals be calculated? Light moves 30 cm in 1 ns, so if time
differences can be calculated to an accuracy of 0.1 ns, then
direction could be resolved to an accuracy of 3 cm/10 m ~= 3 mrad.

Alternately, would something like a pinhole camera work? What I mean
here is: imagine a cubic metal box, 1 m on its side, with a vertical
slit, about 1 cm wide down one of its vertical faces. On the
opposite face, there are detectors for detecting radio waves. If the
elevctromatnetic ratiation coming into the box can only go in
through the slit, and goes in a straight line, then knowing which
detectors are lit up would allow someone to tell where the
radiation was coming from. It may be that, depending on the
wavelength, the incoming radiation would be diffracted by the slit
and would get spread all over the detectors. If this is the case,
perehaps multiple slits could be used, and the diffraction pattern
would differ dependent on the angle with which the radiation strikes
the slitted face? (because the radation at each slit would be
out-of-phase with the radiation at other slits). Has anything like
this been tried?

It is
hard enough for the average "rest of the world" intel unit to DF an
old fashioned non-hopping transmitter if the radio operator uses good
RTO procedures--trying to pluck enough of these random
fractional-second bursts out of the ether to determine a direction is
more difficult by a few orders of magnitude.

What methods are used to do DF?

--
"It's easier to find people online who openly support the KKK than
people who openly support the RIAA" -- comment on Wikipedia

(phil hunt) wrote in message ...
(I'm not an electronic engineer, so I've cross-posted this to some
newsgroups which might be able to give informed comment on a number
of points.)

On 23 Sep 2003 05:51:41 -0700, Kevin Brooks wrote:
(phil hunt) wrote in message ...
[regarding battlefield internet]
The signal must be such that the extended receiver can hear it. So
others can too, in principle. (Though detecting the signal and
knowing where it's from aren't the same thing). I'm not a radio
engineer but I can imagine a few ways how direction-finding might
work; for example place two (or 3) detectors a few meters apart
and calculate the time delay between each one receiving the signal.

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

So what? Unless you know the frequency hopping plan ahead of time
(something that is rather closely guarded), you can't capture enough
of the transmission to do you any good--they use a rather broad
spectrum.


over a
pretty wide band of freq's (this is why synchronization of the radios
on a time basis is critical to succesful operation of the net).

So the frequency changes are pre-determined on a time basis?

Yes.


If there is a radio receiver, is it better able to detect/deceive a
signal whgen it knows the frequency in advance? Or can it "sniff"
for lots of frequencies at a time and pick out what looks
interesting?

Both radios have to be loaded with the same frequency hopping (FH)
plan, and then they have to be synchronized by time. When SINGCARS
first came out the time synch had to be done by having the net control
station (NCS) perform periodic radio checks (each time your radio
"talked" to the NCS, it resynchronized to the NCS time hack); failure
to do this could result in the net "splitting", with some of your
radios on one hack, and the rest on another, meaning the two could not
talk to each other. I believe that the newer versions (known as
SINCGARS EPLRS, for enhanced precision location system) may use GPS
time data, ensuring that everyone is always on the same time scale.

Yes, you can set up to scan various nets (we did so for command post
operations where we wanted to monitor multiple nets), but they all
have to be on that same time hack, and you have to have each net's FH
plan loaded; you can't just decide to operate it like a police scanner
and listen in on whoever you choose to.


If two receivers, placed say 10 m aparet, both pick up a signal, how
accurately can the time difference between the repetion of both
signals be calculated? Light moves 30 cm in 1 ns, so if time
differences can be calculated to an accuracy of 0.1 ns, then
direction could be resolved to an accuracy of 3 cm/10 m ~= 3 mrad.

The fact is that the direction finding (DF'ing) of frequency agile
commo equipment is extremely difficult for the best of the world's
intel folks, and darned near impossible for the rest (which is most of
the rest of the world); that is why US radio procedures are a bit more
relaxed than they used to be before the advent of FH, back when we
tried to keep our transmissions to no more than five seconds at a time
with lots of "breaks" in long messages to make DF'ing more difficult.


Alternately, would something like a pinhole camera work? What I mean
here is: imagine a cubic metal box, 1 m on its side, with a vertical
slit, about 1 cm wide down one of its vertical faces. On the
opposite face, there are detectors for detecting radio waves. If the
elevctromatnetic ratiation coming into the box can only go in
through the slit, and goes in a straight line, then knowing which
detectors are lit up would allow someone to tell where the
radiation was coming from. It may be that, depending on the
wavelength, the incoming radiation would be diffracted by the slit
and would get spread all over the detectors. If this is the case,
perehaps multiple slits could be used, and the diffraction pattern
would differ dependent on the angle with which the radiation strikes
the slitted face? (because the radation at each slit would be
out-of-phase with the radiation at other slits). Has anything like
this been tried?

Hey, I just *used* the critters and was fortunate enough to attend new
equipment training from the manufacturer when we got it; suffice it to
say that use of FH makes DF'ing a remote concern, pretty much
eliminates any concern over jamming (even broad band jamming can only
take down a small percentage of the available spectrum, making voice
transmissions still very clear), and the use of FH combined with
crypto key makes it darned near impossible for the bad guy to decypher
it in any realistic timely manner.


It is
hard enough for the average "rest of the world" intel unit to DF an
old fashioned non-hopping transmitter if the radio operator uses good
RTO procedures--trying to pluck enough of these random
fractional-second bursts out of the ether to determine a direction is
more difficult by a few orders of magnitude.

What methods are used to do DF?

You'd have to find a signals intel puke to answer that one (but you
can rest assured that any really good methods/systems remain
classified).

Brooks

On 23 Sep 2003 20:00:32 -0700, Kevin Brooks wrote:

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

So what? Unless you know the frequency hopping plan ahead of time
(something that is rather closely guarded), you can't capture enough
of the transmission to do you any good--they use a rather broad
spectrum.

OK, I now understand that DF generally relies on knowing the
frequency in advance.

BTW, when you say a rather broad spectrum, how broad? And divided
into how many bands, roughly?

Both radios have to be loaded with the same frequency hopping (FH)
plan, and then they have to be synchronized by time. When SINGCARS
first came out the time synch had to be done by having the net control
station (NCS) perform periodic radio checks (each time your radio
"talked" to the NCS, it resynchronized to the NCS time hack); failure
to do this could result in the net "splitting", with some of your
radios on one hack, and the rest on another, meaning the two could not
talk to each other. I believe that the newer versions (known as
SINCGARS EPLRS, for enhanced precision location system) may use GPS
time data, ensuring that everyone is always on the same time scale.

That would make sense.

If two receivers, placed say 10 m aparet, both pick up a signal, how
accurately can the time difference between the repetion of both
signals be calculated? Light moves 30 cm in 1 ns, so if time
differences can be calculated to an accuracy of 0.1 ns, then
direction could be resolved to an accuracy of 3 cm/10 m ~= 3 mrad.

The fact is that the direction finding (DF'ing) of frequency agile
commo equipment is extremely difficult for the best of the world's
intel folks, and darned near impossible for the rest (which is most of
the rest of the world); that is why US radio procedures are a bit more
relaxed than they used to be before the advent of FH, back when we
tried to keep our transmissions to no more than five seconds at a time
with lots of "breaks" in long messages to make DF'ing more difficult.

So transmissions of 5 seconds tend to be hard to DF? Of course, with
the battlefield internet, a text transmission will typically be a
lot less than 5 s (assuming the same bandwidth as for a voice
transmission, i.e. somewhere in the region of 20-60 kbit/s).

transmissions still very clear), and the use of FH combined with
crypto key makes it darned near impossible for the bad guy to decypher
it in any realistic timely manner.

Modern crypto is good enough to withstand all cryptanalytic
attacks.

--
"It's easier to find people online who openly support the KKK than
people who openly support the RIAA" -- comment on Wikipedia

"phil hunt" wrote in message
. ..

transmissions still very clear), and the use of FH combined with
crypto key makes it darned near impossible for the bad guy to decypher
it in any realistic timely manner.

Modern crypto is good enough to withstand all cryptanalytic
attacks.

Thank you Admiral Doenitz...

L'acrobat wrote:

"phil hunt" wrote in message
. ..

transmissions still very clear), and the use of FH combined with
crypto key makes it darned near impossible for the bad guy to decypher
it in any realistic timely manner.

Modern crypto is good enough to withstand all cryptanalytic
attacks.

Thank you Admiral Doenitz...
------------
He's right. Major breaththrough of all possible barriers, the RSA
algorithm. Uncrackable in the lifetime of the serious user, and
crack is entirely predictable with improved computing power and
can be lengthened to compensate.

-Steve
--
-Steve Walz ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public

"R. Steve Walz" wrote in message
...
L'acrobat wrote:

"phil hunt" wrote in message
. ..

transmissions still very clear), and the use of FH combined with
crypto key makes it darned near impossible for the bad guy to
decypher
it in any realistic timely manner.

Modern crypto is good enough to withstand all cryptanalytic
attacks.

Thank you Admiral Doenitz...
------------
He's right. Major breaththrough of all possible barriers, the RSA
algorithm. Uncrackable in the lifetime of the serious user, and
crack is entirely predictable with improved computing power and
can be lengthened to compensate.

The fact that you and I think it is unbeatable, doesn't mean it is.

"lifetime of the serious user" what ********, you and I have absolutely no
idea what sort of tech/processing power will be available 10 years from now,
let alone 30.

"and crack is entirely predictable with improved computing power" of course
it is...

Ask the good Admiral how confident he was that his system was secure.

Damn near as confident as you are and that worked out so well, didn't it?

(phil hunt) wrote in message ...
On 23 Sep 2003 20:00:32 -0700, Kevin Brooks wrote:

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

So what? Unless you know the frequency hopping plan ahead of time
(something that is rather closely guarded), you can't capture enough
of the transmission to do you any good--they use a rather broad
spectrum.

OK, I now understand that DF generally relies on knowing the
frequency in advance.

BTW, when you say a rather broad spectrum, how broad? And divided
into how many bands, roughly?

It uses the entire normal military VHF FM spectrum, 30-88 MHz. ISTR
that the steps in between are measured in 1 KHz increments, as opposed
to the old 10 KHz increments found in older FM radios like the
AN/VRC-12 family, so the number of different frequencies SINGCARS can
use is 58,000.


Both radios have to be loaded with the same frequency hopping (FH)
plan, and then they have to be synchronized by time. When SINGCARS
first came out the time synch had to be done by having the net control
station (NCS) perform periodic radio checks (each time your radio
"talked" to the NCS, it resynchronized to the NCS time hack); failure
to do this could result in the net "splitting", with some of your
radios on one hack, and the rest on another, meaning the two could not
talk to each other. I believe that the newer versions (known as
SINCGARS EPLRS, for enhanced precision location system) may use GPS
time data, ensuring that everyone is always on the same time scale.

That would make sense.

If two receivers, placed say 10 m aparet, both pick up a signal, how
accurately can the time difference between the repetion of both
signals be calculated? Light moves 30 cm in 1 ns, so if time
differences can be calculated to an accuracy of 0.1 ns, then
direction could be resolved to an accuracy of 3 cm/10 m ~= 3 mrad.

The fact is that the direction finding (DF'ing) of frequency agile
commo equipment is extremely difficult for the best of the world's
intel folks, and darned near impossible for the rest (which is most of
the rest of the world); that is why US radio procedures are a bit more
relaxed than they used to be before the advent of FH, back when we
tried to keep our transmissions to no more than five seconds at a time
with lots of "breaks" in long messages to make DF'ing more difficult.

So transmissions of 5 seconds tend to be hard to DF? Of course, with
the battlefield internet, a text transmission will typically be a
lot less than 5 s (assuming the same bandwidth as for a voice
transmission, i.e. somewhere in the region of 20-60 kbit/s).

ISTR the old guidance was to keep transmissions no longer than 5 to 7
seconds without a break (a break normally was announced as part of the
message, followed by release of the mic key, then rekeying and
continuing the message).


transmissions still very clear), and the use of FH combined with
crypto key makes it darned near impossible for the bad guy to decypher
it in any realistic timely manner.

Modern crypto is good enough to withstand all cryptanalytic
attacks.

Only if it were so...but thank goodness it is not. Otherwise we would
have lost the value of one of our largest and most valuable intel
programs, and NSA would no longer exist. Even the cypher keys used by
our modern tactical radios (said keys being generated by NSA at the
top end, though we now have computers in the field capable of "key
generation" using input from that source) are not
unbreakable--instead, they are tough enough to break that we can be
reasonably assured that the bad guys will not be able to gain any kind
of *timely* tactical intel; enough computing power in the hands of the
crypto-geeks and they can indeed break them, but it will probably take
them a while, not to mention the time to get the data into their hands
in the first place.

Brooks

On 25 Sep 2003 06:23:38 -0700, Kevin Brooks wrote:
(phil hunt) wrote in message ...
On 23 Sep 2003 20:00:32 -0700, Kevin Brooks wrote:

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

So what? Unless you know the frequency hopping plan ahead of time
(something that is rather closely guarded), you can't capture enough
of the transmission to do you any good--they use a rather broad
spectrum.

OK, I now understand that DF generally relies on knowing the
frequency in advance.

BTW, when you say a rather broad spectrum, how broad? And divided
into how many bands, roughly?

It uses the entire normal military VHF FM spectrum, 30-88 MHz. ISTR
that the steps in between are measured in 1 KHz increments, as opposed
to the old 10 KHz increments found in older FM radios like the
AN/VRC-12 family, so the number of different frequencies SINGCARS can
use is 58,000.

More than one 1 kHz slot is likely to be in use at anyone time,
since you need enough bandwidth for voice. Say 20, then about
1/3000th of the frequency space is in use at any one time.

Modern crypto is good enough to withstand all cryptanalytic
attacks.

Only if it were so...but thank goodness it is not.

Oh? So who can break AES/Rijndael?

Otherwise we would
have lost the value of one of our largest and most valuable intel
programs, and NSA would no longer exist. Even the cypher keys used by
our modern tactical radios (said keys being generated by NSA at the
top end, though we now have computers in the field capable of "key
generation" using input from that source) are not
unbreakable--instead, they are tough enough to break that we can be
reasonably assured that the bad guys will not be able to gain any kind
of *timely* tactical intel; enough computing power in the hands of the
crypto-geeks and they can indeed break them,

True, but "enough" happens to be more than all the computers in
existance right now, or likely to exist.

Assume: there are 1 billion computers, each of which can check 1
billion keys/second.

Then a brute-force search on a 128-bit keyspace would take about
10^60 years.

--
"It's easier to find people online who openly support the KKK than
people who openly support the RIAA" -- comment on Wikipedia

(phil hunt) wrote in message ...
On 25 Sep 2003 06:23:38 -0700, Kevin Brooks wrote:
(phil hunt) wrote in message ...
On 23 Sep 2003 20:00:32 -0700, Kevin Brooks wrote:

No. Paul is correct, DF'ing a "frequency agile" (or "hopping")
transmitter is no easy task. For example, the standard US SINCGARS
radio changes frequencies about one hundred times per *second*,

Bear in mind that I'm talking about automated electronic gear here,
not manual intervention. Electronics works in time spans a lot
quicker than 10 ms.

So what? Unless you know the frequency hopping plan ahead of time
(something that is rather closely guarded), you can't capture enough
of the transmission to do you any good--they use a rather broad
spectrum.

OK, I now understand that DF generally relies on knowing the
frequency in advance.

BTW, when you say a rather broad spectrum, how broad? And divided
into how many bands, roughly?

It uses the entire normal military VHF FM spectrum, 30-88 MHz. ISTR
that the steps in between are measured in 1 KHz increments, as opposed
to the old 10 KHz increments found in older FM radios like the
AN/VRC-12 family, so the number of different frequencies SINGCARS can
use is 58,000.

More than one 1 kHz slot is likely to be in use at anyone time,
since you need enough bandwidth for voice. Say 20, then about
1/3000th of the frequency space is in use at any one time.

Modern crypto is good enough to withstand all cryptanalytic
attacks.

Only if it were so...but thank goodness it is not.

Oh? So who can break AES/Rijndael?

Otherwise we would
have lost the value of one of our largest and most valuable intel
programs, and NSA would no longer exist. Even the cypher keys used by
our modern tactical radios (said keys being generated by NSA at the
top end, though we now have computers in the field capable of "key
generation" using input from that source) are not
unbreakable--instead, they are tough enough to break that we can be
reasonably assured that the bad guys will not be able to gain any kind
of *timely* tactical intel; enough computing power in the hands of the
crypto-geeks and they can indeed break them,

True, but "enough" happens to be more than all the computers in
existance right now, or likely to exist.

Assume: there are 1 billion computers, each of which can check 1
billion keys/second.

Then a brute-force search on a 128-bit keyspace would take about
10^60 years.

Well, I guess you ought to inform Congress that the NSA is a sham, then.

Brooks