Re: A couple of quick replies

Derk Groeneveld wrote:

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> On Sat, 24 Mar 2001, Barclay, Tom wrote:
>
> > Derk:
> >
> > 1) EW - Any smart EW no longer does broad spectrum jamming. You
don't have
> > the power to manage that kind of jamming (or so I've been told by
people in
> > the Canadian intelligence community with military EW backgrounds).
So,
> > assume that the jamming is sophisticated. In order to jam, you must
emit.
> > Modern ESM techniques are extremely sophisticated too and locating
any unit
> > that goes active (regardless of what type of emission) is going to
be none
> > too difficult by 2183.
>
> SMART jamming is not broad spectrum. But even on narrow spectrum,
there's
> a BIG difference between noise jamming (basically shouting so loud the
> sensor can't hear) and responsive, deceptive jamming, where you try to
> confuse a radar with false range or direction information.
>
> Now, assuming ultra high speed digital memories are commonplace in the
> future, deceptive jamming becomes ever more attractive. Then, it's
> suddenly very hard to discern between a true radar echo, and a signal
> generated by the jammer. As the signal strength emitted is now in the
same
> order of magnitude of the radar _echo_, it's MUCH harder to _detect_,
or
> to lock a HARM on (since you don't want the harm to lock on genuine
radar
> echoes). Of course, this is between stand off and on board jamming.
>
> > Even now, you go active, and you attract HARMs from
> > air delivery plus artillery. That is why most EWOCs, when operating,
will
> > operate for a time then get the heck out of dodge to avoid the
> > counterstrikes. It takes a bit of time to localize you.... your
window of
> > work... but figure this will reduce in the future.
>
> Yes, if you go for noise jamming, you'll announce yourself to the
world as
> a target, for sure. Andyes, in the future you'll probably be dead
sooner.
> Howebver, this still isn't truly intelligent jamming.
>
> > You can't be totally
> > sneaky and still effectively muck up a powerful transmission. It
will always
> > be paper scissors rock, but nowadays EW assets that go active that
don't
> > move shortly tend to get whacked. Or at least so goes the theory on
this
> > side of the big pond. It was the doctrine I observed in CF EW forces
our
> > infantry unit was protecting in Europe on excercises in the late
eighties. I
> > don't think that much has changed, except how quick you get
localized...
>
> A _lot- has changed in the _type_ of jamming employed. Of course,
jamming
> the opponents communications is WAY different from jamming sensor
> attempts. To jam communications, you have to interfere with HIS use of
the
> bandwidth (therefore need more power), instead of slightly
misdirecting a
> sensor attempt.
>
> Mm. Maybe I shoiuld dig up my EW textbook and try and make a coherent
> story here, sometime ;)
>
> > 2) Advanced Sensors - My take is opposite - advanced sensors are
passive.
> > The better the quality, the less need for active sensors, hence the
less
> > detectable.
>
> Basic sensors are by definition passive, unless you include 'Hello??
> Anyone there?". Anything above basic will probably be to some degree
> active. But yeah, I can think of some very advanced passive ones as
well.
> So maybe it would be: Basic - passive. Enhanced - active  & passive.
> Advanced: Mainly passive, some active etc.

Actually quite the opposite.  Truly basic sensors (more basic than the
basic level
sensors described in MT), such as those mounted on freighters are
entirely active
because they only have to avoid objects, not shoot at them, and power is
cheap
while sensitivity is expensive.  FT warships (including the Komarov and
Von
Teghettof) are actually too small and maneuverable for the double
transmission
delays of active over passive sensors to provide an adequite fire
control
solution.

Warships will not use active sensors in the same fashion as the civilian
vessels.
Warships will use their active sensors to take a snapshot of a bogie
first
detected by passive sensors.  The snapshots are taken with microwave
"flashcubes"
derived from explosively pumped, high powered microwave weaponry, which
are
destroyed by the energies that they focus on the target (vessels carry a
large
number of these small and expendable devices).	The vessel's passive
sensors (and
those of other vessels in the formation) use the reflection of the
single pulse to
determine range, size and shape of the target.	Because these images are
used to
aid in the passive tracking, they need not be taken very often.  As the
pulse is
very short and the target does not know when the pulse is arriving,
there is very
little that the target can do besides being unreflective.  A method
under
investigation to defeat stealth coatings are broad-spectrum flash cubes
powered by
small nuclear devices.

The PDS's employ a more conventional active sensor system as the range
is much
smaller and a fire control solution is needed sooner than would be
available from