Tuesday, March 10, 2015

How to Disrupt Drones - Background

There is an interesting article over at WTOP.com about work supposedly being carried out by the Secret Service in their attempts to prevent a re-occurrence of the recent ‘drone incursion’ at the White House. I’m very surprised that they are doing their testing in Washington, DC, but that may just be because there are more air space controls in place there than most anywhere else in the country. But, all of that aside, the discussion of disrupting drone activities is an important one for all critical infrastructure security, one that I have pretty much ignored until now.

This will be the first of a short series of articles about the use of drones as weapons against critical infrastructure and what can be done to reduce the risk of their successful employment as a weapon.

What is a Drone

Thanks to the War on Terror just about anyone in the world that hears the word ‘drone’ first thinks of war birds like the Predator equipped with Hellfire missiles, taking out al Qaeda leadership or killing innocent civilians depending on your point of view. This is for all intents and reasonable purposes a war plane. While some commentators (and a couple of popular TV shows) have warned about terrorists gaining control of such weapons, defending a facility against such attacks is a job for the US Air Force not the local chemical facility security manager. So I will ignore such sophisticated weapons until such time as North Korea or Iran starts selling them at Wal-Mart prices to various terrorist organizations.

No what is of legitimate concern to security managers at critical infrastructure locations is the much more common and less sophisticated remotely piloted vehicles that the FAA is calling sUAV (small unmanned aerial vehicle). Weighing less than 55 lbs this class of vehicles encompasses everything from the small toy helicopters you buy in the mall (the FAA calls these micro UAV if they weigh less than 4.4 lbs) to hobiest type vehicles like the quad copter that crashed at the White House, to sophisticated surveillance aircraft being introduced into service around the country.

The limited payload size of these aircraft means that they will be unlikely to be used against hardened targets like nuclear reactors. They would, however, be able to carry a small explosive or incendiary device, which means that they could be capable of initiating an attack on a chemical facility.

More likely, however, is that the surveillance capability of these types of vehicles could by terrorists to gain detailed knowledge of the layout and security measures at a targeted facility in preparation for an attack, or even for command and control activities during an infiltration.

A much more likely use of these vehicles will be surveillance activities by non-violent activist groups (think GreenPeace) wanting to document perceived or alleged environmental or ethical violations at chemical facilities. Similarly, I expect that we will see an increasing number of news organizations using these sUAV for acquiring videos for the evening news.

Drone Capabilities

Because of the wide variety of potential vehicles it is going to be difficult to describe a specific set of characteristics for this class of aircraft. In order to remain in the sUAV classification the FAA does intend to limit the maximum speed to 100 mph and require that an operator be in constant control of the device.

Fixed wing versions of these drones are going to have some limitations on their maneuverability just because they require air flow over/under their wings to maintain lift; they won’t be able to hover for instance. Their low weight, however, will mean that they will be able to fly relatively slowly without stalling. Low speed also means pretty good maneuverability.

Rotary winged versions will probably not reach the 100 mph speed, but they will be very maneuverable and will be able to hover and reverse. Spinning the aircraft body in place will also be a rather unique capability.

Motive power will be electric for the smaller aircraft and internal combustion engines will be common on the larger versions. The electric versions will be relatively quiet; the IC’s not so much.

All of these sUAV will require real-time electronic communications with their controller/pilot. This means a WiFi, cell phone or radio link.


To date I haven’t seen any specific discussion of weapons actually being deployed on any of these small aerial vehicles, but it is just a matter of time. Because of the size of the platform, however, there will be some limitations.

You can just about forget these vehicles being used as gun platforms. It wouldn’t be too hard to mount a small barrel and firing device, but any cartridge of significant caliber will provide so much recoil that the flight controls will be seriously disrupted. This will be less true of the larger, fixed-wing aircraft, but the engineering required to design and build a system with any significant size (caliber) and accuracy will be extensive. I know some gun-nuts that would be interested in the challenge, but I don’t see anything happening in this arena soon.

Rockets would be much better suited to this type of platform. The problem would still be size/weight restrictions. The aiming and firing mechanism is going to be a design challenge. The small size of the warhead for any but those mounted on the largest platforms in the class will limit the strike utility of these weapons.

The most effective way to weaponize these vehicles would be with explosives. Bombing will certainly be tried, but I suspect that the accuracy will be WWI level; certainly nothing like the precision weapons delivery we’ve come to expect of sophisticated aerial platforms. Much more effective will be the flying bomb where the explosive payload never leaves the aircraft. A couple of pounds of plastic explosive will be well within the capability of all but the smallest micro UAV. This is the type of weaponization that would be the cheapest and easiest to engineer; I expect that it will be the first to be employed in the wild.

There is also the possibility that these aircraft could be employed in an electronic warfare mode. Many large chemical manufacturing facilities use wireless communications techniques in their control system deployments. Using a drone as a platform to intercept, jam or mimic these communications could provide a unique attack capability. This mode of attack would require a great deal of sophistication and multiple areas of expertise to implement. In the near term this is a low probability attack method.

There are other less sophisticated ways to employ sUAV as weapons. The easiest, of course, is to employ the aircraft as a direct kinetic weapon, just fly it into the target. This was a well publicized method used by a very limited number of Japanese pilots in WWII. The higher the speed capability the more effective this will be as an attack method.

There are other attack techniques that could be used in specialized situations. I’ll give just couple of examples that come to mind. Attach a long copper wire to the drone and fly it into an electric sub-station; exciting things will happen. Or fly a drone through a flare at a refinery; great balls of fire.

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