Acoustic Resonance Disruption (LRAD-class)
Long-range acoustic device aimed at small commercial drones to induce resonance in MEMS gyroscopes and IMUs, destabilizing flight. Honest assessment: largely a research curiosity and anti-personnel hailer — effective only against unprotected hobbyist quads at short range. Included for completeness; not a primary military C-UAS solution.
How It Works
A high-output acoustic emitter (140+ dB) directs sound at the drone's resonant frequency (typically 19–27 kHz for common MEMS gyros). Resonance corrupts gyro output, the flight controller receives garbage data, and the drone tumbles or auto-lands. Hardened military gyros, vibration-isolated mounts, and IMU sensor fusion defeat the attack.
Technical Specifications
Advantages
- + Non-kinetic, no debris, no RF emission
- + Doubles as anti-personnel hailer / area denial
- + No spectrum coordination required
Disadvantages
- − Effective only against unhardened commercial drones
- − Trivially defeated by vibration isolation or sensor fusion
- − Short range, narrow beam, needs precise aim
- − Dangerous to nearby friendly personnel without hearing protection
Tactical Deployment Tips
- ▸ Use only for low-end commercial UAV intrusion (perimeter security, civilian sites)
- ▸ Do not rely on as a frontline military C-UAS — assume any military drone is hardened
- ▸ Mind hearing-protection requirements for own personnel
Limitations & Vulnerabilities
- ⚠ Ineffective against any drone with isolated/redundant IMU
- ⚠ No effect on optical or inertial navigation degradation beyond gyro
- ⚠ Atmospheric attenuation degrades beyond ~150 m
Drones It Defeats
Drone types ranked by how well this system defeats them — tap any drone for details
⚠ How Adversaries Defeat This System
Active enemy adaptations observed in the field — distinct from passive limitations above
- ▸ Vibration-isolated IMU mounts (standard on any military-grade flight controller)
- ▸ Multi-IMU sensor fusion that rejects the corrupted gyro
- ▸ Standoff release beyond 150 m
Sources & Further Reading
- ▸ Son et al. — 'Rocking Drones with Intentional Sound Noise' (USENIX 2015)
- ▸ Genasys — LRAD product family documentation