Defense against UAV's

wrote:
[snip]


The 35mm Millennium gun would qualify - that's designed to fire the
AHEAD ammo I mentioned - but I'm not so sure about the Bofors 57mm. In
the AA mode that uses radar aiming and proximity fuzes, and I'm not
sure if either would be sensitive enough to respond to a small stealthy
UAV.

If naval guns can hit incoming artillery shells then they can hit a
slower moving plane. Shrapnel shells can overcome problems with
accuracy. Unlike machine guns, shells can also be used to protect other
ships.

Many UAVs are flown under remote control. Radio direction finding may
permit the location of its headquarters to be found.

Andrew Swallow

wrote:
Didn't the Serbs shoot down a U.S. UAV with a helicopter door gun over
Bosnia a few years back?

Helicopter guns might be a cheap way to deal with low performance
UAV's,
assuming you have a sensor that can detect the UAV and direct the Helo
to the target.
If we are talking about a swarm of UAVs, shooting them down with Helos
is way too slow.
And you better pray the UAVs don't carry Stingers or something similar,
helos are sitting ducks...

Jack Linthicum wrote:
wrote:
According to:

http://en.rian.ru/onlinenews/20060530/48833304.html

An Iranian UAV was able to circle a U.S. aircraft carrier undetected
for 25 minutes.

With U.S. forces making increasing use of UAV's, the inevitable
question becomes:

How can we protect our forces against UAV's when other countries or
terrorist
organizations start using them against us?

Did you notice this is a Russian news agency reporting on what an
Iranian spokesman said?

Thanks for pointing that out. It was wondering how it was known to
have been circling for 25 minutes, if it was undetected.

--

FF

wrote:

...

The idea is to take them out long before your last line of defense.
Taking them out early means missiles and/or aircraft. Both will have
problems locking on low signature slow flying targets. And both can be
overwhelmed/depleted by swarm attacks..

So maybe the solution is to suround the fleet with a swarm of
cheap friendly semi-autonomous UAVs to detect and shoot
down approaching hostile UAVs with a cheap weapon like
a light machine gun.

--

FF

wrote:
Jack Linthicum wrote:
...
The mention was of swarms which implies swarms of signals
not necessarily, if mostly autonomous UAVs are used

which then implies if I have an ECM craft up and I get lots of radiation from one
direction I will send a message to that source. The decoys may work the
second time but not the first or third.
??

The control point will be that, singular, one command directing all of the UAVs
from one spot.
Ever heard of fiber optics communications? Set-up multiple cheap
antennas for communication, and link them with fiber optics to your
safe hidden command centre. Why you guys always assume that the bad
boys are dumb beyond recognition alludes me...

What the hell is an autonomous UAV? and to what purpose? You need a
unique signal for each aircraft otherwise they will all turn left at
the same time. On the first shot you may hit a bunch of decoys but also
the target or targets. Especially if the decoys must be deployed under
the control of the central command. Second time the decoys may stay on
and the command freqs shut down. Third time no one cares and fires
enough weapons to take care of the site and the decoys.

I have heard of fiber optic communications, those antennas will still
radiate and believe it or not the U.S. military can figure out where
the command point is physically. The bad guys do not have to be smart
or dumb, they will be overwhelmed by the amount of crap the U.S. can
throw at tem. It's the occupation afterwards that is the sticking point.

wrote:

The problem here is that it could be a kind of 'asymmetric warfare', in
that the costs and problems of the defence are potentially far more
costly than those of the attackers.

It would seem to me to be likely that a simple software code
modification would allow an Aegis system to detect smaller, slower
returns (I would expect that right now, those get filtered out so that
seabirds don't cause spurious readings on the radar scopes). If you
pick up a weak signal that doesn't belong there, just have AEGIS dump
all of its radiating power down a relatively tight beam and zorch a
little lightweight unshielded UAV right out of its electronic mind.

On 31 May 2006 01:51:29 -0700, wrote:


rb wrote:

The US navy in particular seems to have seen the writing on the wall for
some time now, hence (I would assume) part of the reason for their
interest in developing the 'Millenium' gun and expressed interest in the
naval 57mm cannon.
http://www.lockheedmartin.com/wms/fi...=400&jsi=false
http://www.navyleague.org/sea_power/dec_04_46.php

The 35mm Millennium gun would qualify - that's designed to fire the
AHEAD ammo I mentioned - but I'm not so sure about the Bofors 57mm. In
the AA mode that uses radar aiming and proximity fuzes, and I'm not
sure if either would be sensitive enough to respond to a small stealthy
UAV.

I would have thought that the 3Ps range gate fusing would be ideal for that
?

A UAV with a spinning propellor is not going to be overly stealthy, hard to
see yes, invisible to radar ?



greg
--
If you want venality, if you want ignorance, if you want drunkenness,
and facility for being intimidated; or if, on the other hand, you
want impulsive, unreflecting, and violent people, where do you look
Do you go to the top or to the bottom?

wrote in message
ps.com...

Keith W wrote:
wrote in message
ups.com...

Jack Linthicum wrote:

Almost all the arguments one sees here are based on the fact that UAVs
are dumb and if you can take the comms out, you are fine. I am not
sure that will hold for long, especially if the UAVs are used against
ships on open sea, in fair weather, in 'kill every warship you see'
mode - which all makes the autonomous decision making of the UAV so
much easier.

That of course also makes spoofing and the use of decoys much easier
and makes the user rather unpopular with any other seafarers. It'd
be something of a pity if your UAV's decided to attack the local
fishing fleet instead of the USN battle group. Given the number of
offshore
rigs and support ships as well as tankers in the Persian Gulf such
indiscriminate weapons would seem rather unattractive to the Iranians
as an example.


If you are using video imaging (backed up by some other, e.g.
IR/passive EM sensors),
I suspect it is a graduate student's exercise in image recognition to
distinguish a warship (esp. aircraft carrier) from an oil
rig/tanker/finshing ship. Especially if you are flying slow.

As a software engineer I'd suggest you are wrong. If such recognition
is so easy how did an Argentine aircrew drop bombs on an
American tanker in 1982 believing it was a RN Carrier ?

A UAV with realtime video image recognition and IR sensors is unlikely
to be especially cheap

Chaff and flares might foil simple radar/IR seekers, but I can't see
how would they defeat video imaging sensor (+good software behind it).



Design for minimal communication and bandwidth needs
(just for higher level commands/coordination) - much tougher to detect
and jam.


It is easy to imagine a swarm of UAVs used as very sheap relatively
slow (200km/h) flying cruise missiles with small warheads, designed to
attack radars and similar on-ship targets that can be seriously damaged
with a small warhead (spray a shotgun of darts with wavy aluminium
tails into that phased array and see what it can do afterwards).


200 km/hr UAV's are going to be rather vulnerable to all forms
of active defence including point defence missiles like RAM
and to CIWS.
Yes. That's why you want them to be really cheap and use swarming.

With real time image recognition systens cheap will be quite a trick.

On
the other hand RAM is IR homing and the IR signature of a 100hp piston
engine is negligible compared to the IR signature of a rocket/jet
engine of the current antiship missiles.


But not small enough to be invisible

Phalanx (or other gun-based CIWS) should be effective, but has rather
short range (and not THAT much reloads, if you are dealing with a huge
swarm). I suspect it is also looking at targets with much higher radar
signature and very different characteristics.


Thats just software and rather easier to do than deciding if
that 1000 ft long ship is a carrier or VLCC

The CIWS mounts look rather distinctly and will obviously be among the
targeted areas of the ship. You don't need that much of a warhead to
put CIWS radar ot of commission - so perhaps an UAV with 200kg warhead
can actually carry 8-12 short range missiles designed for homing on
CIWS radar and launch them while being out of range of CIWS.


Earth Calling Planet Esteban - a UAV with 200kg warhead and
8-12 sub missiles will be neither small nor cheap.


Another possiblity is to actually fly high (say 5-8km) so that the UAV
will have to be attacked by missiles and/or aircraft, not CIWS guns,
and drop (homing) submunition from there, gravity doing the delivery
work. You will want to make these UAVs stealthy, to make the locking of
the missile seeker real difficulty (and postpone finding the UAVs as
much as possible).

There is a tradeoff between sophistication and cost (and reliability,

And you are now propsing sophisticated, costly and probably unreliable.


simple systems are easier to debug/design correctly). However, a
country like China/India or even Iran should be able to mass produce
good enough UAVs for peanuts (i.e be able to field thousands of them).
The key term being 'good enough', not 'super duper, all weather, high
reliability and long service life'.

But with real time image recognition, organic SEAD and large warheads

DUH !

Keith



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Jack Linthicum wrote:
wrote:
Jack Linthicum wrote:
...
The mention was of swarms which implies swarms of signals
not necessarily, if mostly autonomous UAVs are used

which then implies if I have an ECM craft up and I get lots of radiation from one
direction I will send a message to that source. The decoys may work the
second time but not the first or third.
??

The control point will be that, singular, one command directing all of the UAVs
from one spot.
Ever heard of fiber optics communications? Set-up multiple cheap
antennas for communication, and link them with fiber optics to your
safe hidden command centre. Why you guys always assume that the bad
boys are dumb beyond recognition alludes me...

What the hell is an autonomous UAV?
An UAV that can fly itself using an autopilot (see cruise missiles) to
predefined destination, look around and try to see and identify ships
and perhaps asks the controller for help in making crucial decisions
(attack/ignore/move elsewehere).

and to what purpose?
Increase survivablilty/success of the system. Little, low bandwidth
communication = difficult to detect & jam.

You need a unique signal for each aircraft otherwise they will all turn left at
the same time.
You are still thinking 'remote controlled airplane'. Think 'remote
command'. The UAVs are capable of flying themselves, they just might
need advice from time to time. You don't tell each single aircraft what
to do exactly, you just send a message to the whole swarm: "20% of you
attack the ship, priorities ar A,B,C, the rest go to box [X,Y] and
search for targets there" Each UAV rolls a dice, if it is in the 20%,
it rolls a dice to choose among the identifiable targets on the ship
(phased arrays, CIWS radars, bridge, aircraft on deck, catapult). They
actual flying and execution of the commands is done autonomously. (It
will be a bit more complicated, but this is the basic idea.)

On the first shot you may hit a bunch of decoys but also
the target or targets. Especially if the decoys must be deployed under
the control of the central command. Second time the decoys may stay on
and the command freqs shut down. Third time no one cares and fires
enough weapons to take care of the site and the decoys.
No decoys needed. The UAVs themselves are cheap enough so that would be
waste. Perhpas you can have a hi/lo mix of UAVs with high end
sensors/UAVs with cheapo sensors (as the sensors are likely the
costliest part of the UAV), the cheapo UAVs acting as a sort of decoys
(but still being able to inflict damage, just with a bit lower
probability.)

I have heard of fiber optic communications, those antennas will still
radiate
With autonomous UAVs, the radiation will be intermittent and low
bandwidth. Using spread spectrum/frequency agility or whatever, it
will be difficult to pick up out of the noise. And antennas are cheap
and you can have plenty of them....

and believe it or not the U.S. military can figure out where
the command point is physically.
:-) Like they had sooo much intelligence on WMD in Iraq. Or their
capability to take out Serbian tanks/guns/command centers. ;-) Somehow
I don't think Iran is a country in which USA has a lot of good
humint....

And tt's not like you need an air conditioned bunker holding 100s of
people and computers, anywhere in the vicinity where you can connect to
your fiber network is good enough. The squad doing the control might
decide themselves in the morning of the attack where they want to be,
not even their superiors need to know...

The bad guys do not have to be smart
or dumb, they will be overwhelmed by the amount of crap the U.S. can
throw at tem.
You know, never underestimate your adversary...
Somehow, the Serbian military was not particularly overwhelmed, the
civilian infrastructure was....

It's the occupation afterwards that is the sticking point.
Well, I don't think US will be dumb enough to try to occupy Iran. But
with Dubya you never know....

wrote:
[snip]


Even if SAMs could deal with these small UAVs, the problem would be
that the enemy could then just send over hordes of very cheap UAVs
(without the expensive sensor kit) to soak up the SAMs - a very
cost-effective way of degrading your enemy's capabilities. Unless and
until a small and cheap "anti-UAV" homing missile can be developed, I
think appropriate guns (and ammo) provide the best answer.

NATOs weapons are expensive because:
a. they are made in tiny quantities.
b. are built to work at the north pole, in a snow storm during a nuclear
war.

If you relax the specifications a little something much cheaper can be
made. For instance in the middle east the sensor kit for a UAV could be
a mobile phone with built in camera. Reprogram the phone to take a
picture every minute and radio it back. Such a UAV and camera could be
mass produced for less than £1,000.

Longer range at night would require a civilian infra-red surveillance
camera and a bigger plane but still very low cost.

Andrew Swallow