The U.S. Department of Defense (DOD) has spooled up to take the lead in drone warfare with its Replicator 1 program initiative. Securing $500 million in funding in 2023 for “attributable UAVs, DOD is planning another half of a million dollars for the Replicator 2 program. The Replicator initiatives are intended to bring on large volumes of potentially existing capability through increased manufacturing and technological capability. AeroVironment received Rep 1 funding for Switchblade-600 kamikaze drones, which had previously been used successfully in Ukraine, and various initiatives are also underway with many U.S. manufacturers of unmanned surface vessels (USVs), including Anduril’s Dive-LD autonomous underwater vehicles.

Having launched contracts increasing the available volume of attack UAVs (loitering munitions), it has been decided that the Replicator 2 program will go after the protection of U.S. forces from enemy drone attacks. Both sides in Ukraine have built up their UAV attack capability, and as a consequence, both sides now need better defenses against offensive UAV threats. DoD has also learned from experience in the Middle East, where its naval assets have suffered from kamikaze UAV attacks in the Gulf.

Inexpensive, commercially available UAVs loaded with explosives and remote control and proximity detonators have proved effective weapons. The next phase of Replicator will seek funding in 2026 for counter small-unmanned aerial system (C-sUAS) initiatives, building up existing capability and technology and developing improved defense capabilities.

Several c-UAS systems have been developed and fielded in recent years, but DOD’s efforts on Directed Energy Weapons are being intensified. High power microwave (HPM) systems can be used to jam UAV communications and disrupt onboard drone electronics such as navigation, guidance, sensors and control systems. Its only drawback is that effectiveness diminishes rapidly with the range from the HPW transmitting antenna. This is due to the increased dissipation of microwave energy in the air with the square of the distance traveled – straight physics. Nevertheless, if you can pump enough power out of the transmitting antenna, say in a narrower beam, you may still be able to cover enough distance to disable an attacking swarm of adversary UAVs, even if it ends up being close in as the UAVs approach the target.

Based in Los Angeles, Epirus recently delivered its Leonidas Expeditionary HPM system under a U.S. Navy contract. The system is mounted on a towed trailer, with the HPM antenna mounted on a turntable to enable directional aiming for a more dynamic ground-based defense against drones. Previous testing has demonstrated the system’s capability to “fry” single and multiple UAVs.

A U.S. Army 2023 contract allowed Epirus to prototype four of the Leonidas systems, which have been delivered to the agency and are potentially slated to find active service in the Middle East. This real-world test aims to shake down the systems under high-stress defensive situations, providing feedback for future improvements if required. The situation on the ground clearly demands improved defensive capability.

Earlier tests of high-power laser defenses in the region allegedly encountered some difficulty with durability and heat dissipation for 50Kw vehicle-mounted systems, while 20Kw laser systems performed better.

It would seem that the high-intensity microwave beams used by the Leonidas systems might be more usable by ground forces. Epirus has reported that a unique approach to power management was one of the initial core elements developed for the Leonidas system, which may affect the ability to form high-power microwave beams.

Earlier defensive approaches have included rifle fire, shoulder-mounted missiles, expensive guided missile defenses, anti-drone drones that collide or throw nets, jamming of the control signals, and, of course, GNSS jamming and/or spoofing. HPM “frying” of multiple drones at a time may be another key defensive approach that may make drone attacks harder for adversaries to inflict on our forces on the battlefield.

So, the next phase of this game could be to develop counter-counter-drone technologies to defeat the defensive systems—this may be a never-ending process.