It's actually a potentially serious problem:

The technology for remote-controlled light aircraft is now highly advanced, widely available -- and, experts say, virtually unstoppable.

Models with a wingspan of five metres (16 feet), capable of carrying up to 50 kilograms (110 pounds), remain undetectable by radar.

And thanks to satellite positioning systems, they can now be programmed to hit targets some distance away with just a few metres (yards) short of pinpoint accuracy.

Security services the world over have been considering the problem for several years, but no one has yet come up with a solution.

Sounds like a job for the hive mind of the blogosphere.

We may still see more government controls on the radio-controlled aircraft hobby as with model rocketry, classifying them as "munitions".

The US faced a similar threat before - the Japanese "balloon bombs".

Who here wants to see an X-prize type award to the model rocketry club that can product tiny surface to air missiles, suitable for large-scale deployment along borders and shores, to intercept an aircraft with a two-meter wingspan?

G.o.o.g.l.e "Tam5" for information on a home-made aircraft that crossed the Atlantic in 2003.

(The naughty word filter prevented me from including this in the previous post. I'm trying many different variations to find out what it doesn't like.)

I don't think the radar detection problem is the real issue. After all, you can always make the detection technology good enough that only a few small objects could get through. Or even set up fences and other barracades. This is especially true when you consider that many targets can be overflown without causing a stir.

My take is that the real danger here is that one can guide a terrorist attack without being put directly at risk. Laser-guided missiles are a similar danger, but something has to be close enough to guide the missile in.

I believe solutions are already available for areas where terrorist attacks are likely. First, can't GPS be locally distorted and blocked? Just make it so GPS and Galileo don't work in Washington, DC and other high threat areas.

Second, electronic countermeasures would seem effective. Not only can you jam guidance signals, but you might be able to destroy unshielded electronics with EMP pulses. It also seems to me that laser systems that could intercept incoming artillery shells might slow down or destroy an incoming drone.

For low flying craft, you could have a instant popup metal fence or net (say powered with an explosive charge) that could take off wings or otherwise slow down the vehicle.

I really think this is overblown. We've seen the lack of skill demonstrated by the terrorists. I'd say, given their past performance, the likelihood of them pulling off any kind of a serious attack at zero.

But, if we're concerned about protecting key assets (like DC), then my vote is on a Phalanx-style point-defense weapon. A buddy of mine in the Navy told me a story about a destroyer he was on that would lob 5" shells across the stern of an aircraft carrier equipped with the Phalanx gun, and they'd watch the gun shoot the shell out of the sky.

Sounds pretty effective to me.

Laser cannons (they're coming) will take care of the hard kill requirement. The big problems, though, will involve our OODA loop. Is something there? What is it? Where is it going? Does it pose a danger? Is there another explanation? Do we engage?

Oops, it's too late--it already completed its mission, which might have been just to get close enough to test your reaction or spy on something.

Or, it might not.

Karl's ideas may work, but have they'll have a lot of secondary effects which will prove quite unpopular. Jamming GPS will take a lot of car-based local navigation devices out of action, although I suppose a radius outside the highly-populated area may be effective. EMP would take out the electronics on the threatening craft, as well as a lot of cell phones and iPods, again an unpopular action.

The laser weapons have the advantage of not dropping shells on civilians during the inevitable false positives. I hope occasional flaming birds are acceptable. though.

I hope occasional flaming birds are acceptable, though.

One suspects that the Avian-American community won't be totally down with that.

But, if we're concerned about protecting key assets (like DC), then my vote is on a Phalanx-style point-defense weapon. A buddy of mine in the Navy told me a story about a destroyer he was on that would lob 5" shells across the stern of an aircraft carrier equipped with the Phalanx gun, and they'd watch the gun shoot the shell out of the sky.

Dave G, I got to agree. Terrorists don't see to do much with advanced technology.

I was thinking the laser cannon rather than a phalanx system would be feasible in a urban environment since bullets come down eventually and the phalanx gun spews a lot of them.

As far as unpopular goes, Washington, DC security already does a lot of unpopular things (like closing streets or cordoning off main routes for the coming and going of the President).

From the article: "While billions have been spent on ballistic missile defense, little attention has been given to the more imminent threat posed by unmanned air vehicles"

Apples and oranges. Whereas the result of a successful ballistic missile attack (with nuclear warhead) could be millions dead; a successful attack by a overgrown RC airplane with a 100 pound conventional warhead at the very worst could be expected to kill maybe a 100 people. So it seems to me the spending of billions defending against the former makes sense whereas hand wringing over the remote possibility of the latter does not. Even if armed with chemical or biological material, it would take a swarm of the RC “bombers” to deliver the death toll equivalent of one ballistic missile. Not to say that the possibility should be considered and planned to defend against, but for Mr. Hambling to insinuate that this is a more pressing issue that ABM technology is either disingenuous or outright ignorance.

EMP would take out the electronics on the threatening craft, as well as a lot of cell phones and iPods, again an unpopular action.

Depends on who you ask. ;-)

That is a bit extreme though. I'd think a couple guys armed with shotguns would be more than enough; we're not talking about bringing down a 747 here.

This is a version of the problem
"Any civilization can be destroyed by smart people with a desire to do so."

A group of 10 well organized people with kites, string and large rolls of aluminum foil could black out half the country.
Just launch simultanious attachs on the long distance power transmission facilities in several deserted places. History has proven again and again
that the power tranmission system is brittle.

As for the RC planes, You can get RC powered jets that go over 200 mph and weigh up to 100lbs,
you can buy off the shelf 5Hz GPS receivers,
and simple gyros,combine these together
and one could probably penetrate almost any high value target.

Perhaps we need a wing of hunter/killer drone planes to fly CAP and down attacking drones by ramming into them.

ultrasound?

A shell doesn't maneuver. It's not easy to hit a maneuvering very small plane (

Shells can have time fuses rendering them somewhat harmless (how harmless exactly, I don't know), as long as you aim high so they have time to explode in the air. (And no air traffic close by of course.)

sigh, I introduced a "less than" sign that mucked up my post.

With a small plane I mean something less than 2 meters wing span. If somebody radio controls it, it can maneuver very unpredictably and quickly, meaning you need a very high velocity round or laser or close distance, you can't lead the target much. Of course, a maneuverable plane probably can't carry much payload or is slow. What if they fly ten at once from different directions?

The phalanx system has only some 1000 m/s round velocity, although the rapid fire solves some problems (like the z dimension "match"). If the distance is, say, 300 meters, and the plane moves sideways at 10 m/s, it's moved 3 meters during the 0.3 s the shell took to reach it.

This is where I shamelessly plug an earlier post of mine on Chicago Boyz, Steps Toward an "Active Shield"?. It's about bats (the kind that eat bugs, not the kind that hit balls), among other things.

mz, you should be thinking of acceleration. 25 gee of acceleration over 0.3 seconds is roughly 2.5 meters of displacement. Alternately, the thing coming in could be armored enough so that the defense system couldn't penetrate.

And launching lots of stuff is already a known means of getting around virtually any defense. For example, Tom Clancy describes such an approach in his war novel "Red Storm Rising" where the USSR attacks Western Europe (set in the mid 80's) and in particular takes on a US carrier group that was sent across the Atlantic to support the war. Here the missiles all come from one direction, but IIRC there's a couple hundred missiles in the air at once.

For example, there are mortar designs out there that can spew a hundred or more small rounds in a few seconds. As I recall, it operates much as an array of roman candles.

Karl, are you thinking of Metal Storm?
www.metalstorm.com

I hope occasional flaming birds are acceptable, though.

A solution for bird flu! Bonus!

> With a small plane I mean something less than 2 meters wing span.
> If somebody radio controls it, it can maneuver very unpredictably
> and quickly, meaning you need a very high velocity round or laser

Fortunately, we have one of those, lasers that is. It's called the Tactical High Energy Laser (THEL), and in tests it shot down Katyusha rockets and artillery shells. Work is currently underway on a mobile version called MTHEL.

Mike

Indeed I was, JP. The weapon I recalled actually was classified as a grenade launcher not a mortar and was only one of several weapons designed by this company. Check out the lower picture in this 2003 CNN story.

Karl, metal storm was covered in Discovery Channels new series "Future Weapons" just a few weeks ago (and on Rand's site several months ago). It is a technology, more than a single weapon, and can be utilized in almost any weapon firing a projectile with a self contained charge.

I agree, the big problem is improved sensing devices, but when we have that technology, our stealth vehicles will be obsolete. Knocking small RC planes out of the sky will be easy compared to finding them.

Build defensive RC aircraft. Scatter noise sensors around the building, and when you hear the whine of a small 2-stroke engine the defenders get launched.

"A shell doesn't maneuver. It's not easy to hit a maneuvering very small plane"

I doubt planes this small are manuvering much.

"Shells can have time fuses rendering them somewhat harmless (how harmless exactly, I don't know), as long as you aim high so they have time to explode in the air. (And no air traffic close by of course.)"

The shrapnel is going to come down somehere.

The tactical solution of shooting down incoming is not the answer. The strategic solution of infiltrating and eliminating the enemy makes more sense to me.