System Architecture
Four layers of capability, each independent — no single point of failure
Layered Architecture
Onboard Autonomy
Zero communication needed
Each drone navigates independently using its own IMU, altimeter, and waypoint logic. No external input required. This is the always-on baseline that keeps every drone safe regardless of what happens to inter-drone links.
Passive Acoustic Sensing
Zero data exchange
Every multirotor produces distinctive acoustic signatures. Each drone listens to its neighbors and estimates bearing and approximate range from the sound alone. No encoding, no protocol, no coordination overhead.
Active Acoustic Ranging
Minimal signaling
Precise peer-to-peer distance measurement via acoustic time-of-flight. Requires only brief tone exchanges between drones. Combined with Layer 2 bearing, this gives sub-meter relative positioning.
Acoustic Data Channel
Strategic overlay
A low-rate (20–40 bps) coordination data link carried over acoustics. Transmits position updates, formation commands, and status. This is the highest-capability layer but the system does not depend on it.
Graceful Degradation
Each layer operates independently. Higher layers enhance capability but are never required for safe operation. The system degrades gracefully rather than failing catastrophically.
Layer 4 data channel lost
Layers 2–3 maintain formation through passive bearing and active ranging. Drones know where their neighbors are and avoid collisions.
All acoustic sensing lost (Layers 2–4)
Layer 1 autonomous navigation keeps each drone on its individual mission. No coordination but no collisions due to pre-planned deconfliction.
Full capability (all layers active)
Sub-meter relative positioning, 20–40 bps coordination data, and real-time formation control across 12+ drones.
Design Principles
No Single Point of Failure
Every drone is self-sufficient at Layer 1. Higher layers add capability but never create dependencies that can bring down the swarm.
COTS Hardware Only
The full system runs on commercial off-the-shelf microphones and existing flight controller hardware. Under 25 g and under $25 per drone. Zero custom fabrication.
Validated Results
All performance numbers come from rigorous simulation with corrected methodology: proper statistical tests, confidence intervals, and no oracle assumptions.