The growing accessibility and utilization of off-the-shelf and military unmanned aerial systems (UAS) have made robust defenses essential.

The United States therefore is developing technologies that neutralize UAS, thus protecting critical infrastructure and deployed forces and ensuring airspace security around the world.

Effective counter-UAS (C-UAS) defense depends on a layered and flexible architecture and a variety of approaches.

Multi-layered defense

Detection and tracking are the cornerstone of C-UAS technology.

Radar systems can detect UAS at long ranges and in rugged weather, while cameras and electro-optical and infrared sensors offer real-time visual tracking and classification.

C-UAS systems employ radio frequency detection systems that monitor the electromagnetic spectrum -- especially between 70MHz and 6GHz -- to identify the radio signals that drones and their operators exchange.

Drones often have unique characteristics, allowing detection systems to determine their make, model, location, serial number and even operator location.

Acoustic detection adds more protection. By identifying the unique sound signatures of a UAS, acoustic sensors are valuable in environments with limited radio frequency emissions or where UAS are operating autonomously.

Meanwhile, artificial intelligence now processes data from sensors rapidly and can automatically track and classify emerging drone threats.

Threat disruption

Once operators discover a threat, they can destroy UAS through conventional kinetic strikes or "soft-kill" technologies such as electronic warfare and jamming.

Electronic jamming systems can sever communication between a UAS and its operator. Doing so often triggers an emergency landing or a default return to sender, or disables a UAS altogether.

Forcing a UAS to land simplifies capturing and studying it. At the same time, soft-kill technology facilitates the interruption of transmissions by intelligence, surveillance and reconnaissance UAS.

Net-based countermeasures, such as net guns or interceptor drones, enable troops to capture drones without destroying them or the data they hold.

A broad array of kinetic countermeasures is possible, particularly for high-risk threats. Conventional firearms, kinetic interceptors and directed-energy weapons all can counter drones.

High-energy lasers can target and destroy drones at ranges of 200 meters to 2.5km. Even a basic laser pointer can degrade drone navigation.

Flexibility

US-developed C-UAS weapons include fixed and mobile systems.

Fixed configurations permanently protect key assets and installations such as airports, government facilities or densely populated civilian centers.

Meanwhile, mobile platforms on tactical vehicles can provide field-based support to maneuver units or to temporary installations.

A key example is the Maneuver Short-Range Air Defense (M-SHORAD) system. Mounted on a Stryker combat vehicle, the system was designed to protect US Army units in the field.

The system includes two four FIM-92 Stinger missiles, an XM914 30mm automatic cannon, an M240 7.62mm machine gun and a multi-mission radar for tracking and detection.

Its directed energy variant, also known as the Increment 2, incorporates a 50kW laser against aerial threats.