Trade Study
Acoustic vs alternative intra-swarm communication approaches
Approach Comparison
| Approach | Range | Covert | EMCON | SWaP | Noise Imm. | GPS-Denied |
|---|---|---|---|---|---|---|
| Acoustic (Aurora) | 10–50 m | High | Yes | <25 g | High | Yes |
| IR/Optical | 10–100 m | Low | No | Moderate | Poor | No |
| Ultrasonic | 1–5 m | High | Yes | Transducers | Moderate | Yes |
| Magnetic (NFC) | <0.5 m | High | Yes | Coils | High | No |
| RF (BT/WiFi) | 10–100 m | Low | No | Radio | Low | No |
Aurora operates at 10–50 m range with <25 g SWaP using all COTS components. Optional 4-mic array extends capability (~$8/drone additional).
Why Not Encrypted RF?
The fundamental problem with RF — even encrypted, low-power, or spread-spectrum RF — is detectability, not confidentiality.
RF Detection Problem
- • Hostile SIGINT/EW detects any RF emission
- • Detection range far exceeds communication range
- • Even LPI waveforms reveal swarm presence
- • GPS jamming degrades all RF-dependent systems
Acoustic Advantage
- • Acoustic propagation confined to local environment
- • Propeller noise is already present (zero signature increase)
- • Orthogonal to RF jammers
- • No electromagnetic signature at any range
In EMCON-restricted environments, any RF transmission — regardless of encryption or spreading — violates mission constraints. Acoustic communication provides coordination without electromagnetic emission.
Concept of Operations
A drone swarm operates in a GPS-denied environment under active electronic warfare. RF communications are restricted. The swarm launches and transitions to close formation (10–50 m separation).
Aurora's acoustic channel provides coordination with zero electromagnetic emission. Each drone maintains awareness of its neighbors through passive acoustic sensing. When the data channel is available, drones exchange position and status at 20–40 bps. When it is not, passive sensing and active ranging maintain formation.
Cooperative acoustic positioning maintains sub-meter relative localization without GPS. No additional hardware beyond COTS microphones. No detectable signature beyond the propeller noise the drones already produce.