C-UAS Passive Defenses

Assess effectiveness, cost, and fielding requirements for C-sUAS passive defenses to protect HVAA assets in CONUS environments.

• Acosta, Capt. Alan A., "The Drone Dilemma: Leveraging Existing Technologies to Counter the Threat of Low-Cost Combat Drones," AFGC thesis, 2024, 42 pgs.
  • While not directly discussing passive physical defenses like nets or HVAA protection, Acosta evaluates existing C-sUAS systems strictly on their cost-effectiveness, targeting range, ease of logistics, and fielding requirements. He highlights the use of passive radio frequency detection sensors, such as those integrated into the Mobile-Low, Slow, Small-Unmanned Aircraft Systems Integrated Defeat System (M-LIDS) currently being fielded to U.S. Army divisions. Acosta emphasizes that integrating these passive detection methods alongside non-kinetic electronic warfare disruption is crucial for building a cost-effective, layered C-sUAS defense strategy.
• Adams, Lt. Col. Nicholas, "Killing Drones, Saving Bones: Cost Effective Counter-Small UAS Options for an Agile Force," AFGC thesis, 2024, 44 pgs. 
  • This paper addresses the cost, effectiveness, and fielding requirements of C-sUAS defenses, specifically emphasizing the constraints of operating in the Continental United States (CONUS). Adams evaluates various kinetic and non-kinetic solutions based on quantitative costs and qualitative metrics like expected lethality, technology readiness, logistics ease, and the ability to avoid collateral damage. To protect domestic infrastructure, he concludes that fielding non-kinetic systems—such as the Tactical High-Powered Operational Responder (THOR), Phaser High-Power Microwave (HPM), and Counter-Electronic HPM Extended-Range Air Base Defense (CHIMERA)—is necessary for CONUS bases, whereas forward-deployed locations can safely utilize kinetic options.
• Allen, LtCol Zachary S., "Invisible to the Drone's Eye: Leveraging New Concepts and Technology to Safeguard Marine Aviation against the Unmanned Threat," AFGC thesis, 2026.
  • Allen addresses the query by evaluating both passive and active defenses to protect high-value aviation assets (such as the $125 million CH-53K helicopter) from sUAS swarms, although the context is expeditionary operations rather than CONUS. To complicate the adversary's "Find" and "Fix" targeting phases, the paper assesses the effectiveness of passive physical defenses like camouflage netting and infrared-inhibiting blankets, alongside passive multi-sensor detection platforms like Radio Frequency (RF) scanners and electro-optical/infrared (EO/IR) cameras. Allen argues that the fielding requirements for these systems must include high mobility and integration into the squadron level, noting that relying solely on active kinetic interceptors is too costly (creating an unsustainable 56,000-to-1 cost-exchange ratio) to defend against cheap sUAS.
• Godoy, Maj. Luis, "UAS Threats in Asymmetric Warfare," AFGC thesis, 2025.
  • Godoy contributes to the query by assessing the effectiveness, cost, and fielding requirements of passive C-sUAS detection systems, though his focus is primarily on protecting Special Operations Forces rather than CONUS HVAA. The paper evaluates commercial off-the-shelf passive RF detection systems (such as the Dedrone RF-300 or Aaronia AARTOS), which cost in the $50,000 range and fulfill the fielding requirement of being highly portable, backpack-capable, or vehicle-mounted. Godoy assesses these passive sensors as highly effective because they continuously monitor RF activity and geolocate sUAS operators to provide early warning without emitting a signature that would expose friendly positions to counter-attack.
• Heistuman, Tom J., "Dusting off the Defensive Playbook: Analyzing Cold War Defensive Strategies for Modern Threat Environments," SAASS thesis, 2024.
  • Heistuman partially answers the query by evaluating the cost and effectiveness of passive defenses for HVAA (strategic bombers) stationed at CONUS and OCONUS locations, though the threat context is long-range missiles rather than sUAS. The paper assesses passive defense strategies—specifically the hardening of airfield infrastructure and the dispersal of aircraft across multiple locations—to determine how they complicate adversary targeting and alter the cost-benefit calculus of an attack. Heistuman notes that while these passive fielding requirements are expensive, historical RAND studies proved them highly cost-effective, demonstrating that hardening decreased the cost per surviving bomber by 35% despite increasing upfront procurement costs.
• Johnson, Capt. Kyna M., "The Threat of Unmanned Aerial Systems against Mobility Air Forces," SOS AUAR, 2020, 10 pgs. 
  • Johnson partially answers the question by outlining the severe threat that sUAS pose to Mobility Air Forces (which are considered HVAA) across CONUS military installations, though her assessment focuses on active rather than passive defenses. The paper assesses the fielding requirements and effectiveness of active counter-drone systems like Dronebuster, SkyNet, and the Tactical High-Power Operational Responder (THOR), noting that THOR can be fielded rapidly from a 20-foot container transported by a C-130. While Johnson emphasizes that CONUS bases face varied sUAS threats from both commercial off-the-shelf systems and nefarious actors, she argues that the Air Force must shift its focus earlier in the kill chain to effectively mitigate these vulnerabilities before launch, rather than focusing on passive mitigation strategies.
• Stevens, Maj. Brent C., "The Rise of Commercial Drones: Investigating Tomorrow's Asymmetric and Hybrid Threats," AFGC, 2021, 57 pgs. 
  • Details the emerging threats of commercial-off-the-shelf (COTS) drones operating in the homeland and breaching critical infrastructure, but focuses on electronic/cyber payloads rather than passive defenses for aircraft.
• Wright, Maj. Jeremy A., "Attack of the Drones! U.S. Military Application of Counter Small UAS Operations," AFGC thesis, 2025, 36 pgs. 
  • Wright answers the prompt's focus on passive defenses by analyzing emerging battlefield tactics from the Russia-Ukraine war to identify effective, low-cost countermeasures against sUAS. He details how physical passive defenses—such as utilizing better camouflage for troops and vehicles, dedicating sentries to watch for drones, and deploying nets and tripwires to detonate explosive-equipped sUAS early—organically evolved as highly effective battlefield adaptations. Wright argues that the U.S. military must learn from these developments, recommending that forces adopt a multi-layered defense approach that thoroughly integrates these passive countermeasures alongside scalable, cost-effective kinetic measures and electronic warfare.