
Stealth, Countermeasures, and ELINT, 1960-1975 - runlevel1
http://www.foia.cia.gov/sites/default/files/DOC_0006122549.pdf
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djyaz1200
The way to defeat stealth is instead of looking for the size of the object
look at speed and trajectory. The B2 famously has the radar cross section of a
honeybee. No problem. I would just build filtering software for my radar that
said show me all the objects of any size (even Bee size) heading my way at
over 300mph. I'm sure this has been done, and it's alluded to in book
Skunkworks (good book btw).

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theoh
Actually a better approach is to use longer wave radar, getting a reflection
from the whole metal airframe as a conductive object rather than just bouncing
waves off the surface. Apparently this technique has difficulties with clouds
but was successful in shooting down an F117 in the Balkans.

~~~
teeks99
Another way is bi-static radars. Stealth is generally designed to prevent
returns from going back to the sender, with the downside that they get
scattered in all other directions. Just setup a (silent and difficult to
locate) receiving station(s) and give it a communication channel to the sender
(to synchronized), then it will receive the emissions from the sender that
bounce off stuff.

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vonmoltke
Another way of using bistatic radar is to look for holes. Pick a frequency
band that has significant background noise and search for places where the
background is consistently lower than average. Essentially, invert the
detection algorithm. Nice thing about this approach is it can be done non-
cooperatively; that is, the EM sources do not need to be controlled by
whomever is running the receiver.

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Theodores
This story is 'revised'. The original idea of the OXCART was to fly so fast
that it would not be in one place long enough to rise above background noise
on the radar screen. Think of those CRT radar screens and the 'mark'
corresponding to the plane not being a big green dot, but more something that
just would not excite the phosphor and therefore not show.

The OXCART contract was won by Lockheed because Convair had little experience
of black projects plus Lockheed delivered the U2 under time and under budget.
The OXCART A12 was the 12th revision, sure it might have evolved to have
stealth as we know it, however, the original idea really was just to be too
quick to register on the phosphor.

The big problem as far as radar was concerned was the gigantic plume of
exhaust out the back. They tried putting stuff in that to hide it from the
radar, however there were problems with that too.

Anyway, my point, this is revised history.

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Someone1234
> This story is 'revised'. >> Anyway, my point, this is revised history.

This person was a radar / signal intelligence geek who's only work on the
OXCART project seems to be related to electronic jamming and determining the
radar capabilities of the then USSR.

So this entire set of anecdotes are from their perspective. They never claimed
to be in the initial OXCART development group nor did they make claims as to
what OXCART was design to or not to do. All they said was that based on their
data the OXCART would have been trackable on the USSR's radar defence systems.

That isn't revising history in any meaningful way. However you should take
into account that the scope of the anecdote is just a single person's
perspective working in a single field. They also allude to the recently
launched satellites in addition to the U2's shootdown being contributors to
use the Blackbird was never really used over the USSR.

Frankly your concept that the whole basis for the OXCART project was that CRT'
refresh rate was too low to literally draw the aircraft bizarre. First time
I've heard that and Google has no clue about it either ("OXCART CRT"
"blackbird crt" no relevant results). Plus CRT displays have very high refresh
rates (around 89 Hz), so there's that too...

~~~
Theodores
Look at it another way: imagine a camera with a certain shutter speed taking a
picture of a cat. If the cat is asleep in the same place, centre frame, then
the picture will almost certainly be of the cat.

Should the cat wish to not be photographed then the cat could go into one of
those poses used when hunting prey - ears flattened, tail down etc. The cat
will present a smaller cross-sectional area and not be seen as easily. Who
knows, could be mistaken for 'a bumblebee'. This is 'cat stealth' \- see
'ninja cat'.

Alternatively, the cat could just leap past the camera at phenomenal speed.
Most of the exposure will be of the background however there could be some
light blurring where the cat has leapt across the frame of the picture. On
initial inspection a cat would not be seen, just some shadowy/tabby artefacts.

If the camera was one of those early CMOS sensor things and the light levels
were low then the shadowy/tabby artefacts might not make it past the
background noise that came with those sensors.

In this way a sufficiently fast cat could hide in plain sight from a camera
that had an early CMOS sensor. To make extra sure that the cat was 'invisible'
the cat could be instructed to flatten its ears as it rushed through the
frame.

Clearly I wasn't around in the late 1950's, however, I think my analogy
describes how 'early stealth' worked by just being very quick. You should get
the concept now.

In the military/intel or even normal companies knowledge and information isn't
globally shared so maybe the author didn't know some aspects of the project or
those details were not pertinent to what they were doing. I should have cited
sources but cat analogies are more fun.

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jokoon
don't forget that even if stealth is worthless when considering radars, it can
still greatly reduce the distance that radars can detect stealthier aircrafts.

~~~
vonmoltke
The second clause of your statement contradicts the first.

There is a common misconception that stealth is about making things
"invisible" to radar. It is really about reducing the radar signature of a
vehicle as much as possible when viewed from a conventional, colocated
transmitter/receiver type radar. That includes reducing the detection range or
making it harder for fire control radars to get and maintain a lock. One end
of this spectrum is making the aircraft undetectable by some or all radars,
but stealth goes well beyond that.

