It is very likely that weaponized drones will pose an increasing threat to areas outside of the world’s combat zones. These include cities, suburbs, critical infrastructure, large public assemblies, major sporting events, schools, and other situations in which kinetic kill methods for counter-drone defense may present unacceptable collateral risks.
RF jamming is a primary counter-drone technology envisioned by urban and public safety planners worldwide. However fiber optic controlled drones are immune to jamming, and other emerging drone technologies such as autonomous flight erode the viability of RF jamming as a mainstay CUAS doctrine.
A survey of current CUAS-focused media and marketing suggests that gun-type kinetic counter-drone systems are gaining acceptance as an alternative to RF jamming. But these systems pose grave collateral risks for use in populated areas.
Directed energy (laser and high power microwave) CUAS systems are also regularly presented as non-kinetic drone mitigation systems, but these systems appear to have significant practical limitations to deployment that include cost, complexity, and uncertain real world performance.
Nets are a drone-mitigation technology that has always been in the background of the CUAS arms race. They present several compelling advantages such as extremely low cost, minimal collateral risk, and the ability to neutralize hovering drones without requiring the precision of a bullet or beam-based system. The challenge has always been getting the net to the target drone.
It is useful to think of CUAS systems as layers in terms of their effective range. Generally, the longer the range, the more capital-intensive and complex the CUAS system must be. For example, long range laser CUAS systems require extreme levels of targeting sophistication and platform stabilization to name just two major challenges, while close-in CUAS systems can exploit the short detection and engagement requirement to leverage cheap hardware and methods. Low cost and practicality drive widespread adoption. Shorter range CUAS systems simply have an easier task to deal with.
Nets are currently a short distance CUAS mitigation means. Nets could be a great non-kinetic layer if an effective way could be found to get them onto the target drone. Some recent proposals have featured stowed nets being carried by interceptor drones. These are either shot outwards when near the target, or dropped by the interceptor hovering above the target. The physics of this approach seems awkward and likelihood of snagging all but the most well-behaved target drone is remote. There are also ground based net deployment systems, ranging from net cannons to man-portable shoulder-fired nets. But none of these leaves the impression of a strong reliable CUAS defensive layer.
The problem, simply stated, is that nets don’t fly well on their own.
It has been demonstrated that a large (~3 meter diameter) defensive net can be towed behind a small purpose-built rocket. This approach overcomes the range anxiety of nets as CUAS tools. It also extends their effectiveness well beyond any current method. However much development and testing is needed to optimize the aerodynamic and flight characteristics of rocket-towed barriers, and this requires specialized resources and significant investment. Still, a towed net barrier is an attractive non-kinetic CUAS solution in a world where non-kinetic solutions are few and limited.
What is needed is a flight vehicle that can tow a net like a rocket, but which is cheap, plentiful, easy to build, and requires no specialized R&D program.
It turns out that just such an airborne vehicle exists in the form of the rocket drone. These have been gaining currency in the CUAS media space, as well as from the hacker community. 3D printer files of rocket drones are readily available for free online. Because rocket drones repurpose common quadcopter components and 3D-printing methods, they can be produced and fielded using the same supply chains that already support drone production and prototyping.
A typical quadcopter drone relies completely on rotor thrust to stay aloft. A rocket drone has a similar propulsion layout but its unique characteristic is the ability to fly at high speeds, along its thrust axis (longitudinally), during which the rocket drone transitions to a more ballistic flight trajectory that relies on its aerodynamic shape and its control surfaces, combined with symmetric thrust. The rocket drone is small, aerodynamic, and over-powered. In short, it’s more like an actual rocket, with the essential difference that you can build one using a printer and some simple drone hacks. In other words rocket drones are ideal for towing nets. They are cheap and plentiful, and fully accessible to innovation.
The use of a rocket drone to tow a counter-drone net removes all of the logistical barriers to development and deployment of an effective net-based CUAS system. Rocket drones are well suited to vertical launch, and coincidentally this is also the best way to get a towed net off the ground. Rocket drones are maneuverable through selective thrust modulation just like quadcopter drones, so the towed net CUAS would enjoy maneuverability as well as range. The same hardware and software that drive typical quadcopters may be used to create rocket drones. This radically slashes the development time, expense, and barriers to flight testing. Moreover, rocket drone towed nets could be reusable, further lowering their already low cost.
Rocket Drone-Towed Net Barriers offer an unusually high development upside. In a CUAS market starved for effective non-kinetic options, this concept could be transformative.
