C-UAS Glossary: The Language of Counter-Drone
Plain-language definitions of counter-UAS terminology. From acoustic detection to zone defence, what the terms mean and why they matter.
A
Acoustic DetectionDetection and localization of drones through analysis of acoustic signatures (propeller noise, motor vibration). Acoustic systems identify drones by isolating characteristic frequency patterns (typically 150–300 Hz fundamental with harmonics). Effective range: 50–500 meters depending on ambient noise. Limitations: ineffective in high-noise urban environments, requires multiple microphone arrays for triangulation. Often deployed as complementary layer to RF or EO/IR detection.
Air-Burst AmmunitionProgrammable ordnance that detonates at operator-specified altitude (via electronic timer or proximity sensor), fragmenting to create blast effect optimized for small airborne targets (drones). Reduces collateral damage compared to traditional air-defense rounds designed for large aircraft. Cost-per-round typically €400–600 (ammunition only). Deployed primarily on platforms like Rheinmetall Skyranger 30.
AnvilProprietary C-UAS platform developed by Fortem Technologies; multi-rotor drone configured for autonomous threat identification and kinetic engagement. Anvil integrates optical/thermal imaging, autonomous flight planning, and engagement logic. Operates as distributed network (6–12 platforms simultaneously) for large-area perimeter defense.
AutonomyCapability of unmanned system to execute objectives without continuous operator input. In threat context, autonomous drones present detection challenge (operate without transmitting C2 signals). In C-UAS context, autonomous engagement refers to systems authorized to classify and engage threats without per-target operator approval (subject to defined rules of engagement).
B
Broad-Spectrum JammingIndiscriminate RF interference across wide frequency range, disrupting drone C2 and/or navigation signals. Advantages: no protocol library required; effective against diverse platforms and unknown C2 implementations. Disadvantages: high collateral RF interference risk, regulatory compliance challenges, may disrupt friendly/civilian communications. Distinct from selective or protocol-level jamming.
C
C2 (Command and Control)Radio link connecting drone operator to aircraft. C2 signal carries operator input (flight commands) and platform telemetry (battery status, GPS position, sensor data). Typical drone C2 operates on 2.4 GHz ISM band (DJI platforms) or 5.8 GHz (FPV/racing drones). Protocol-level detection systems (Sentrycs, D-Fend) analyze C2 signal structure for threat identification.
C-UAS (Counter-Unmanned Aircraft Systems)Integrated defensive capability addressing drone threat through detection, classification, and mitigation. Mature C-UAS systems layer multiple detection modalities (RF, radar, EO/IR, acoustic) with multi-effector mitigation (jamming, laser, kinetic). Distinct from "drone defense" (broader term) or "counter-UAS" (same meaning, alternate acronym).
ClassificationProcess of determining threat level of detected drone. Classification outputs include: unmanned status (confirmed drone vs. unknown aircraft), platform identity (DJI Mavic 3, Auterion Skynode, etc.), threat assessment (hostile, suspicious, benign), and suggested mitigation (engage, warn, monitor). Classification accuracy depends on detection data richness (RF signature + EO/IR + radar); RF-only classification has 10–30% error rate against diverse platforms.
Collateral DamageUnintended injury/damage to civilians or non-target facilities resulting from C-UAS engagement. Kinetic systems (bullets, missiles) carry inherent collateral damage risk through fragmentation and debris. Non-kinetic systems (RF jamming, lasers) have reduced collateral risk. Procurement authority must define acceptable collateral damage threshold for deployment in specific airspace (zero tolerance for civilian airspace; higher tolerance for military/border areas).
Cost-Per-EngagementTotal cost expended to neutralize single threat. Includes ammunition, power, maintenance allocation, and personnel time. Examples: RF jamming €50–500 per engagement; air-burst ammunition €400–600; laser engagement €100–200; Coyote loitering munition €50,000–80,000 per platform. TCO fundamentally shapes deployment feasibility; high cost-per-engagement limits quantity of threats manageable with fixed budget.
Covered List (FCC)FCC designation added December 22, 2025, prohibiting import and marketing of foreign-made unmanned aircraft systems in the United States. Rule applies to all foreign platforms and integral components; exempts domestically manufactured systems. Impact: disrupts commercial distribution of DJI and European platforms through authorized channels. Gray-market supply persists. Does not regulate operational flight or autonomous/DIY platforms.
Coyote (RTX Loitering Munition)Autonomous loitering munition system produced by RTX (formerly Raytheon). Coyote is small, air-breathing cruise missile designed for counter-drone engagement. Platform launches from pod, hovers/loiters for extended period (45–75 minutes depending on block), and executes autonomous engagement against designated target. Block 3NK variant supports swarm coordination (12+ simultaneous platforms). Cost per platform: €50,000–80,000.
Cyber TakeoverAttack vector attempting to assume operator control of drone through RF link compromise. Threat actor injects spoofed C2 commands, attempting to override legitimate operator input. Defense mechanisms include C2 encryption and authentication protocols (most modern commercial drones implement basic protections). Cyber takeover effectiveness depends on C2 protocol sophistication and adversary cryptographic capability. Distinct from RF jamming (which disrupts C2) or GPS spoofing (which corrupts navigation).
D
D-Fend LabsIsraeli RF-domain detection vendor specializing in autonomous drone identification. Technology analyzes RF behavior (micro-Doppler signatures, autonomous flight patterns) to detect drones independent of protocol library. Advantage: effective against unknown platforms and protocol variations. Limitation: RF-only detection, does not provide detailed platform classification. Deployed at multiple European airports and critical infrastructure sites.
DetectionIdentification of electromagnetic or acoustic signal indicating drone presence. Detection output typically includes: detected position, confidence level, and signal characteristics. Detection does not imply classification (threat level identification) or engagement authorization. Modern C-UAS systems layer multiple detection modalities to achieve high confidence before classification/mitigation.
Directed EnergyEngagement mechanism delivering energy as electromagnetic radiation (laser) or high-power microwave (HPM). Laser systems destroy through thermal damage to sensors/materials. HPM systems damage electronic components through electromagnetic pulse effect. Advantages: speed-of-light engagement, cost-per-shot lower than kinetic rounds. Disadvantages: weather-dependent (laser), limited engagement range (HPM), thermal signature visible, insufficient to destroy platforms (sensor/gimbal damage only).
DroneHunter (Fortem)Proprietary autonomous air-to-air interceptor platform produced by Fortem Technologies. DroneHunter is multi-rotor drone configured for autonomous acquisition, tracking, and kinetic engagement of threat drones through collision/impact. Range: 15–30 km. Endurance: 45+ minutes. Magazine depth: 3–4 successive engagements per sortie. Deployed globally; largest U.S. civilian deployment in 2026 World Cup contract.
E
EW (Electronic Warfare)Defensive use of electromagnetic energy to disrupt adversary systems. In C-UAS context, EW typically refers to RF jamming (disrupting drone C2 or navigation signals). Distinct from cyber warfare (network-based attack) or kinetic engagement. EW effectiveness depends on jammer power, target frequency, and signal characteristics.
EO/IR (Electro-Optical/Infrared)Sensor modality combining visible-spectrum camera (EO) and thermal imaging (IR). EO/IR systems detect drones through optical contrast (visual appearance) or thermal signature (motor/battery heat). Effective range: 500 meters to 5+ km depending on drone size and atmospheric conditions. Advantages: high classification confidence (can identify platform visually); disadvantages: weather-dependent, requires clear line-of-sight, cannot detect through clouds/fog.
F
FAAD C2 (Forward Area Air Defense Command and Control)American military air-defense command system integrating multiple platform inputs (radar, EO/IR, RF detection, gun platforms) into single tactical picture. FAAD C2 provides target correlation, engagement prioritization, and resource allocation. NATO interoperability standard. Rheinmetall Skyranger platforms integrate with FAAD C2 for multi-platform orchestration. European vendors increasingly designing systems for FAAD C2 compatibility.
False Alarm RatePercentage of detections that are not genuine threats (birds, debris, civilian aircraft). False alarms consume resources (operator attention, possible engagement decision overhead). Acceptable false alarm rate depends on deployment context (airport perimeter defense: 3–10%; border surveillance: 5–15%; urban: acceptable only below 5%; military combat: 20%+ acceptable). Protocol-level systems (Sentrycs) achieve lower false alarm rates through protocol verification; RF-only systems higher (10–25%).
FPV Drone (First-Person-View)Drone piloted by operator via video feed from on-board camera. FPV drones typically carry RF video transmitter + low-latency control link (separate from autonomous flight C2). Category includes racing drones (small, high-speed, acrobatic flight) and attack drones (weaponized FPV platforms, increasingly used in conflict). Detection challenge: FPV drones use high-frequency video links (typically 5.3–5.9 GHz) and diverse C2 protocols, complicating protocol-library approaches.
G
GNSS Spoofing (GPS Spoofing)Attack vector transmitting false GPS signals to deceive drone navigation system. Spoofed GPS causes drone to believe it is at different location, disrupting autonomous flight paths or return-to-home behavior. Defense: dual-frequency GNSS receivers (civilian/military GPS signals plus GLONASS, Galileo, BeiDou) with signal cross-correlation. Modern commercial drones implement basic spoofing detection; military platforms use advanced techniques.
Group 1/2/3FAA classification of unmanned aircraft by weight and operational characteristics. Group 1: <25 lbs, low altitude, short range (includes DJI Mavic, most commercial drones). Group 2: 25–55 lbs, moderate altitude (includes Freefly, industrial platforms). Group 3: 55–1,320 lbs, extended operations. C-UAS requirements vary by platform group (Group 1 threats require faster detection/mitigation than Group 3).
H
HEL (High-Energy Laser)Directed-energy system delivering megawatt-class electromagnetic energy as coherent light beam. HEL engagement destroys through thermal ablation (melting/vaporizing materials). Advantages: extremely high speed-of-engagement (light speed), no ammunition consumption, silent. Disadvantages: weather-dependent (atmospheric blooming reduces effective power), limited range outdoors (10–15 km maximum), visible thermal signature. Northern European operators report 50%+ year-round unavailability due to cloud cover.
HPM (High-Power Microwave)Directed-energy system delivering RF energy at extremely high power (gigawatt levels, microsecond pulses) to damage electronics through electromagnetic pulse effect. Advantages: no line-of-sight requirement (propagates through fog/rain), destroys electronics rather than airframe (platforms can be recovered intact for intelligence). Disadvantages: development immature (most HPM systems remain research-phase), range limited (50–500 meters), collateral RF interference risk.
I
IBCS (Integrated Battle Command System)U.S. Army command-and-control architecture integrating air defense, fires, and intelligence sensors. IBCS provides unified view of air picture and automated engagement recommendations. Modern C-UAS systems increasingly designed for IBCS integration; NATO variants developing equivalent interoperability standards.
IFF (Identification, Friend or Foe)System for identifying aircraft as friendly, neutral, or hostile. Civil aviation uses transponders (ADS-B, Mode C) transmitting aircraft ID and altitude. Military uses encrypted IFF codes. Drones generally lack IFF capability (consumer platforms do not emit identification signals). Absence of IFF signal can trigger defensive response (any unidentified aircraft presumed hostile in military/restricted airspace). C-UAS procurement authorities must define IFF requirements (friendly drone identification methodology to prevent blue-on-blue engagement).
J
JIATF-401 (Joint Interagency Task Force-401)U.S. government counter-UAS fusion center located at Hurlburt Field (Florida). JIATF-401 integrates intelligence, operations, and capability development across DoD, DHS, FBI, State Department, and other agencies. Golden Dome is JIATF-401's tactical C-UAS orchestration system. JIATF-401 provides intelligence sharing and standards guidance for U.S. federal C-UAS procurement.
K
Kinetic DefeatNeutralization of threat through physical impact/destruction. Kinetic defeat mechanisms include air-burst ammunition fragmentation, loitering-munition collision, or high-velocity projectile impact. Advantages: proven lethality, weather-independent, high effectiveness across platform types. Disadvantages: debris risk (creates secondary hazard), expensive per engagement, regulatory complexity in civilian airspace, potential for collateral damage.
KuRFS (Ku-Band Radar Frequency Surface)Proprietary radar system (producer: unnamed classified program, speculation includes Hensoldt, Cassidian Air Defence) operating in Ku-band (12–18 GHz) optimized for small unmanned aircraft detection. KuRFS provides detection range 30–100+ km, low false alarm rates, and platform classification capability. Deployed in limited military/critical infrastructure contexts; civilian availability unclear.
L
Layered DefenceMulti-effector C-UAS strategy deploying diverse detection/mitigation mechanisms in successive layers: - Outer layer: Long-range RF detection + wide-area surveillance - Middle layer: Medium-range EO/IR + classification - Inner layer: Close-in acoustic + kinetic engagement
Advantages: single-point-of-failure risk mitigation, adaptation to platform diversity, operational flexibility. Disadvantage: cost (multiple platforms/systems required). Most mature C-UAS operators prefer layered approaches over single-effector solutions.
LIDS (Launching-Interceptor Detection System)System detecting drone launch events through sensor fusion (RF emission profile at startup, thermal signature of motor ignition, acoustic signature). LIDS enables interception during launch phase (aircraft most vulnerable before gaining altitude). Developed for military border defense; civilian application developing.
M
Magazine DepthNumber of targets engageable before weapon system requires reloading or repositioning. Examples: Coyote system 3–4 targets per sortie (limited by fuel); air-burst ammunition magazine capacity 60–120 rounds (depending on aircraft). Magazine depth fundamentally constrains operational capability; high-value targets warrant deep magazines; low-threat environments tolerate shallow magazines (lower cost).
Micro-DopplerRF signal property showing frequency shift due to moving parts (rotating propellers, wings). Each drone platform exhibits characteristic micro-Doppler signature based on propeller speed and geometry. D-Fend Labs technology exploits micro-Doppler to identify autonomous flight (periodic, predictable micro-Doppler pattern distinct from random operator-controlled flight). Advantage: platform-agnostic detection.
MitigationEngagement action reducing threat posed by detected drone. Mitigation mechanisms include: RF jamming (disrupts C2), laser engagement (destroys sensors), kinetic engagement (destroys platform), cyber takeover (assumes control). Successful mitigation results in drone neutralization (landing, return-to-home, crash) or destruction. Mitigation authorization typically requires human operator approval unless rules of engagement explicitly permit autonomous engagement.
N
NASAMS (Norwegian Advanced Surface-to-Air Missile System)NATO air-defense system integrating Tor or Bayraktar missile platforms with advanced radar and C2. NASAMS primarily designed for large aircraft; C-UAS variant development ongoing. U.S. providing NASAMS to Ukraine for air defense; integration of counter-drone capability has been priority since 2023.
O
Open ArchitectureC-UAS system design principle permitting integration of third-party sensors and effectors via standardized interfaces (APIs, data formats). Open architecture contrasts with proprietary/closed systems (requiring vendor-provided integration). Procurement authorities favor open architecture (reduces vendor lock-in, enables multi-vendor solutions). Vendors have conflicting incentives (proprietary maximizes revenue; open addresses buyer preference). EU Counter-Drone Action Plan explicitly mandates open architecture.
P
Pd (Probability of Detection)Mathematical metric expressing likelihood that system detects threat if present. Pd expressed as percentage (0–100%). High-performing RF detection systems achieve 85–95% Pd against known platforms; 40–70% against unknown/anomalous platforms. Pd depends on: target radar cross-section, background clutter level, operator proficiency. Vendors typically claim Pd >90%; independent testing often reveals lower values (5–15% variance is normal).
Protocol-LevelDetection/mitigation operating at drone C2 radio protocol layer. Protocol-level systems (Sentrycs, D-Fend) analyze packet structure, frequency hopping, encryption, and modulation to identify platforms and execute mitigation. Advantages: high classification confidence, selective jamming (minimal collateral RF interference). Disadvantages: dependence on protocol library, vulnerability to unknown/modified protocols, ineffective against autonomous platforms without active C2.
R
RF Detection (Radio Frequency)Sensing of electromagnetic radiation emitted by drone C2 transmitters or navigation receivers. RF detection identifies drone through signal characteristics (frequency, modulation, power). Effective range: 5–50 km depending on transmitter power and antenna configuration. Advantages: long range, all-weather, does not require visual line-of-sight. Disadvantages: does not provide visual confirmation, vulnerable to spoofing/jamming.
RF Jamming (Radio Frequency Jamming)Transmission of RF interference disrupting drone C2 or navigation signals. RF jamming forces drone into loss-of-signal behavior (autonomous return-to-home, land-in-place). Advantages: non-destructive engagement, scalable to multiple simultaneous targets. Disadvantages: regulatory complexity, high RF power requirement (visible to adversary), does not eliminate threat (only disrupts operator link).
Rheinmetall SkyrangerGerman air-defense platform armed with 30 mm cannon optimized for counter-drone engagement. Skyranger 30 fires air-burst ammunition designed for small airborne targets. Skyranger 30 HEL variant adds 10 kW laser for cost-effective engagement. Deployed by Netherlands, Germany, and other European NATO members. Primary kinetic system in European C-UAS market.
S
SAFER SKIESU.S. government coordination framework for counter-drone operations across civilian and military domains. SAFER SKIES establishes protocols for threat intelligence sharing, engagement authorization, and inter-agency coordination. Participating agencies: FAA, DHS, FBI, DoD. C-UAS systems increasingly designed for SAFER SKIES integration.
Sensor FusionIntegration of data from multiple sensor types (RF, radar, EO/IR, acoustic) to create unified threat picture. Sensor fusion reduces false alarm rates (multi-modal detection confirms threat) and improves classification confidence. Mature C-UAS systems (Fortem, Dedrone, Hensoldt) perform real-time sensor fusion. Complexity: sensor data alignment (different detection latencies require temporal/spatial fusion algorithms).
SentrycsIsraeli counter-drone vendor (acquired by Ondas Holdings) specializing in protocol-level RF detection and selective jamming. Sentrycs technology analyzes drone C2 protocols to identify platforms and disrupt operator link. Deployed at European airports and Latin American defense applications. Strength: protocol precision, non-kinetic mitigation. Limitation: protocol-library dependence, vulnerability to autonomous platforms.
SwarmCoordinated operation of multiple C-UAS platforms (or threat drones) executing shared objective. Swarm advantage: increased magazine depth, geographic coverage, resilience to single-platform loss. Swarm coordination requirement: real-time communication and autonomous threat allocation. RTX Coyote Block 3NK demonstrates 12-platform swarm capability. Technology maturation enabling large-scale swarm deployment.
T
TCO (Total Cost of Ownership)Aggregate cost of acquiring, operating, and maintaining C-UAS system over specified period (typically 5–10 years). TCO includes: platform purchase, ammunition, power, maintenance, personnel training, facility costs. TCO drives procurement decisions; systems with high per-engagement cost face constraints on deployment scale. Example: Rheinmetall Skyranger TCO ~€1M annually per platform; RF-only detection systems €100–300K annually.
Thermal BloomingOptical physics phenomenon where high-power laser beam distorts as it propagates through turbulent atmosphere, causing beam divergence and power loss. Thermal blooming is primary limitation of HEL systems in Northern European/temperate climates. Partially mitigated by adaptive optics (adjusting beam shape to pre-compensate for atmosphere) but cannot be entirely eliminated. Results in effective range reduction and targeting difficulty.
V
Vendor Lock-InProcurement risk where buyer becomes dependent on single vendor for critical capability, restricting future purchasing flexibility. Lock-in mechanisms include: proprietary software, non-interoperable data formats, exclusive component sourcing. EU Counter-Drone Action Plan explicitly addresses vendor lock-in through open architecture mandate. Buyers should evaluate vendor lock-in risk when selecting C-UAS systems.
Z
Zone DefenceLayered C-UAS defensive posture establishing successive engagement zones around protected asset. Example: 50 km outer detection zone, 20 km classification/mitigation zone, 5 km close-in kinetic engagement zone. Each zone may employ different sensor/effector types (RF detection outer zone, kinetic engagement inner zone). Zone defense enables graduated response and optimizes resource deployment.
Cross-Reference Index by Topic
Detection Technologies
- Acoustic Detection, EO/IR, RF Detection, Micro-Doppler, LIDS, D-Fend Labs
Engagement Methods
- Kinetic Defeat, Directed Energy, HEL, HPM, RF Jamming, Cyber Takeover
Platforms and Systems
- DroneHunter, Coyote, Rheinmetall Skyranger, Anvil, Sentrycs, FAAD C2, IBCS, NASAMS
Operational Concepts
- Layered Defence, Zone Defence, Swarm, Autonomy, Classification
Regulatory and Procurement
- Covered List, Open Architecture, Vendor Lock-In, TCO, FCC
Standards and Interoperability
- IFF, FAAD C2, IBCS, SAFER SKIES, JIATF-401, NATO STANAG
Performance Metrics
- Pd, False Alarm Rate, Cost-Per-Engagement, Magazine Depth
Physics and Technical
- C2, Protocol-Level, Micro-Doppler, GNSS Spoofing, Thermal Blooming
Key References
For detailed vendor and technology briefings, consult: - Vendor Profile: Sentrycs (030-vendor-profile-sentrycs.md) - Vendor Profile: Rheinmetall (031-vendor-profile-rheinmetall.md) - FCC Covered List and C-UAS (032-fcc-covered-list-briefing.md) - EU Counter-Drone Action Plan (033-eu-action-plan-briefing.md) - February 2026 Newswire (034-february2026-newswire.md)
Glossary Version: 2026-02 Release Last Updated: February 23, 2026 Maintained by: Counter-Drone Information Resource
This glossary is living documentation. Terms, acronyms, and definitions evolve as technology and regulations develop. Send feedback and correction requests to [content contact].