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The real question is how many people within 1000 miles of a target are capable of building and testing a working drone and equipping it with some kind of explosive or other weaponised payload?

Currently that number is extremely low. It will remain low until 3D printing is a complete zero-effort solution - which is going to take a very long time.

The reality is that this kind of open source terrorism is an incredibly unlikely threat. Numerically there are almost no terrorists, and the terrorists that do exist have almost no engineering skills.

Weaponised engineer terrorists would be a scary thing, but they don't exist in non-trivial numbers. And unless something very bad happens, that's unlikely to change.

As for the drone scenario - it's not exactly stealthy. At 50mph there's roughly 20 hours of warning - plenty of time to put up drone catcher nets, or even launch a suicide drone swarm.

It's not that drone attacks aren't a threat, but they're going to need to be more robust than anything a DIY off-the-server design can produce for some time to come.

Where you and I live, there may be no terrorists, and you and I may not be a target, but there are some parts of the world with an overrepresentation of terrorists. ISIS numbered over 100,000 at their peak. What was within 1000 mile range of ISIS held territory? Did ISIS have 100 competent engineers each capable of guiding 10 others? It would be underestimating your enemy to believe they didn’t.

How hard is it to build a Qassam rocket? Over 2000 were launched in 2008. I expect this type of drone would take the same level of engineering skills once the kinks were worked out.

As for the stealth factor. Let’s assume the drones are launched evenly throughout the 1000 mile diameter range, all at the same time. That’s a search area of 3M sq miles, or one drone every 3000 sq miles. Half way through the journey, with T-10 hours, all drones in the swarm could be evenly distributed in 785k sq miles, with one drone every 785 sq miles. An hour away, they’re all in a 7850 sq mile search area, or one drone every 7.8 sq miles. 5 minutes out, still a search area of 54 sq miles, and the drones are spaced out by over 1000 feet. 1 minute out, they’re all a bit less than a mile from the target, but up to 6000 feet up. An army of 10,000 soldiers armed with AR-15s couldn’t hit the drones at this point. 30 seconds out, the drones are 3000 feet up and still out of range. 10 seconds out and the drones are 1000 feet up, barely within range, but it doesn’t matter because they’re all on a terminal trajectory. Now you’re trying to shoot 10000 armed hand grenades falling from the sky. Good luck.

As for drone catcher nets? Let’s say half the drones are each armed with 1 pound of thermite, and ignite during a terminal trajectory from 1000 feet. What’s going to stop 5000 lbs of thermite followed by 5000 lbs of tnt?

These drones can climb to a few thousand feet, and weigh around 10 pounds. Can you visually identify such a drone versus an eagle? At night? When they’re 1000 feet away - 10 seconds from impact?

Can you hear them at 5000ft? 10,000ft? The same RC hobbiest who flew 1888 miles also set an altitude record of 26k feet.

Or they could fly at 50 feet above the ground, obscured by trees. Dismissed as your neighbor flying his RC plane, too low to be seen by radar, and looking like a cell phone in a car for all RF purposes.

Such a swarm goes from almost invisible to the explosive power of an F/A18 in seconds.

Besides the radar signature of a half pound engine, how else can they be detected? They have the same RF signature of a common cell phone.

I can 3D print amazing RC planes in 24 hours. Are they capable of 1888 mile range? No. That took an expert thousands of hours to perfect. But you can probably get an electric powered 3D printed plane capable of flying 50mph for an hour - today. Tomorrow maybe for two hours. In a decade, maybe 4.

There's opensource visual terrain guidance software on github? I would love a link

Here you go: https://github.com/agtbaskara/dsmac-drone

Not sure if I'm missing anything but I only see one commit, which is a readme without further information

Sorry, I just spent 5min researching on Wikipedia on what algorithms are used for this capability and then threw it into Github search. If you wanted to piece together from open source tools, you can probably recreate the capability in OpenCV. Or search on Github.

Ah. Yeah I did a github search and didn't find any other implementations of that algorithm. I'll do some more research though, it seems like an interesting topic

The Israeli’s Iron Curtain is an example of a possible defensive model. Computer controlled machine guns running ML models could probably take down a lot of drones.

Iron Curtain only works for objects that are detected. If the drones are flying at 50 feet AGL, Iron Curtain isn’t going to work as they’re not going to detected by radar, and exploding an Iron Curtain interceptor 50 feet above someone’s house isn’t going to go well. Flying at 10,000 ft, how far away can an RC motor be detected and not look like a bird?

Iron Curtain currently has 10-15 batteries at four launchers per battery with 20 interceptors per launcher. So, 800-1200 interceptors.

With only 1200 interceptors, they can be overwhelmed by distributed terrorists launching simultaneously over a 1000 mile diameter.

Each interceptor is $40k. I expect a drone would be under $500, so you’ve got an 80:1 cost differential. $400M to stop 10,000 drones.

As for machine guns, let’s say the effective range is 2000 yards. You have roughly 60 seconds to engage all targets. Assume 100 rounds fired to successfully terminate a single drone, with 10,000 drones inbound, you need to fire 1M bullets in 60 seconds. Assuming a machine gun firing at 1000rds/min, that’s 1000 machine guns with perfectly coordinated fire. At $10k/machine gun (a very conservative estimate) how many buildings can you protect for $10M each? Maybe you can protect your capital building with such a lead shield. Your oil refineries.. should probably do that. And now you’ve just sprayed 1M bullets into the air above an oil refinery. Sounds like a bad idea.

And then the terrorist just need to attack with 20,000 drone swarm, and all your facilities are exposed until you double your defenses at all locations.

Financially, I don’t see a solution.

Good points. Your answer would pass the systems design interview and mine would not.

A laser however... probably works for this scenario. But even then, there’s a required dwell time, and more sophisticated terrorists would adapt to using ablative skins, or maybe even materials transparent to the laser wavelength... anything to increase the required dwell time and overwhelm through sheer numbers.

Perhaps the best way would be jamming or hijacking the signal. You could essentially "remove" huge groups of drones at a time.

In order to do that, the electronics inside the drone would need to be susceptible to the electronic noise. Sure, RF shielding from a military grade perspective is difficult, but for this purpose, copper paint surrounding the electronics enclosure may be sufficient. With GPS denied, inertial and visual navigation would be required. Inertial navigation quickly succumbs to accumulated error, but if GPS signals are stopped (jammed) just a few minutes before impact, INS will probably work, given a calm atmosphere, there won’t be much noise inducing turbulence. Visual navigation is much harder, but the advances in machine learning are making this problem trivial.

RF interference is likely the best defense, as quality RF shielding is difficult, especially at extreme frequencies.

AI will be developed to spot them, I'm sure.

I broke a sweat reading.

I have a question, please remember that I am a weapon noob.

Isn't this similar to the hand-held bazookas that are daily fried into Israel & well defended by Iron dome?

Sorry to trigger your anxiety.

The Qassam rockets are basically the same as an Estes model rocket, if constructed from steel, with a TNT warhead. They have a ballistic trajectory, arcing high into the air making them visible to radar, are fired from a location limited by the rocket range (under a few dozen miles) and their exact location at each time until they explode can be calculated and fed into an Iron Dome to intercept. It’s very difficult to coordinate the launch, difficult to launch more than a few simultaneously, and very difficult to get them to land in the same location at the same time. For the defenders, it’s easy to identify where they were launched from (responding with a Hellfire from a waiting Apache), and easy to detect on radar - meter long metal pipes have a much different radar cross section than a bird.

The drones I’m suggesting are possible would have a 1000 mile range. Instead of launching a couple dozen Qassam rocket to be shot down in an evening, the same group could build hundreds of drones, and then launch them over the course of an entire night (or two), from throughout the Gaza Strip, flying not to their destination immediately, but out into the Mediterranean, where they will spread out to fly at a few meters off the ocean until they need to head back to land for their detonation. At that point, these hundreds of drones are all converging on a single location, at a single time, from many different directions. Some high, and some just 50 feet above ground level. They would be very difficult to detect due to their size, altitude (low to avoid radar, or high to avoid human perception), dispersion and speed. From a radar perspective, the metal engine components could be small enough to be outside most radar wavelengths and shaped to minimize radar cross section, while encased in basically a plastic/wooden frame. From radar, it’ll probably look like a bird.

Unlike with the Qassam, it’s not just Sderot which is in range.

Please don't be sorry, it's important to know the risk we face daily. Trillions are spend globally on security, but we are more insecure daily. There needs to be a change in the way we ensure safety. The elected officials who are suppose to do this are too busy in bed with the military industrial complex. Basically the dog is napping and letting the wolfs "watch over" the sheep.

This is a security nightmare. I presumed that the Saudi attack happened due to the incapabilities of Saudi forces. I did read that despite all the fancy toys from Uncle Sam, they dont know how to use the toys well.

How is it compared to the Russian s400? For the trillions that the Americans pour into their defence, do they have some way to fight this "swarm of drones"? Aren't the US leading in drone technology?

Guess in an IT lingo, I can say that distributed systems are better than a monolithic system.

I’m actually impressed with the US and Israeli progress on drone defense. Laser defense is going to be the primary solution and the US and Israel are working diligently. Unfortunately even laser can be swarmed, attacks can be scheduled during fog (lasers don’t work through fog) etc. All systems have weaknesses and ultimately it comes down to an economic battle. Your enemy must not have the resources to use this asymmetric warfare. So, you increase the chance of reprisal attacks working (raising the price of attack from a $500 drone to the attackers life), increase the cost of a successful attack by being able to defend against a large number of drones at the most probable attack location.

The majority of the anti-aircraft defenses are targeted at standard warplanes. The S400 is one of those. Shooting an S400 missile at one of these tiny drones is like shooting a shotgun at a swarm of gnats. You’re not taking out the swarm and you just spent a ton of money to battle something insignificant. The power of these drones comes not from the individual, but the ability to coordinate together. In IT lingo, it would be like trying to battle a DDOS botnet. Further, the S400 is designed to detect a huge airplane. Yes those planes are radar absorbing and reflect radar away from the receivers, but they don’t really resemble a bird. They’re too fast, they go straight, they reflect radar strongly in other directions (to be detected by radar receivers distant from the transmitter) and at their size are capable of being detected by other techniques. These small drones could be made to look like birds from a radar perspective. Hard to justify shooting your S400 at a bird.

The justification for spending more money on defense is that the more you spend, they better you’re protected. I don’t believe that to be completely true, but our investments in laser defenses is justifiable.

All the more reason to support a social media platform that creates extreme groupthink?

Add in Tor and bitcoin, there’s complete anonymity, a funding mechanism and virtually zero possibility for response.

When groups felt wronged, they “voted from the rooftops”. Now they will be able to anonymously vote from their basements.