Technical report
Droneport ATC Coordination: A Factorial Study of Authority, Communications, and Sensing in Urban Air Mobility
TL;DR
- A 9-cell factorial study across 405 simulated vertiport trials: tower vs. self-organized authority, continuous vs. terminal comms, 4 observation modalities.
- Self-org with ADS-B matches tower throughput below ~20 ops/hour, then degrades.
- Silent-cruise drones exceed safe line-of-sight separation thresholds at just 12 ops/hour.
| Simulated trials | 405 |
|---|---|
| Factorial cells | 9 |
| Self-org parity | <20 ops/hr |
| Silent-cruise breach | 12 ops/hr |
Abstract
Nine-cell factorial study comparing tower vs. self-organized coordination, continuous vs. terminal-only communications, and four observation modalities (ADS-B, camera, both, none) across 405 simulated vertiport trials. Self-org with ADS-B matches tower throughput below ~20 ops/hour then degrades; silent-cruise drones exceed safe LoS thresholds at 12 ops/hour. Characterizes the throughput–safety Pareto frontier and broadcast necessity threshold for UAM droneport designs.
Urban air mobility (UAM) infrastructure planning has a coordination problem: who manages the air traffic at a droneport, and how? Centralized tower coordination is the aviation default. Self-organized coordination with broadcast sensing is the drone-native alternative. Neither has been rigorously compared across the operational parameters that matter for real droneport design — traffic density, communication continuity, and observation modality. This paper is that comparison.
Factorial design
Nine experimental cells, 45 trials each, 405 simulated vertiport trials total. The three factors:
- Authority: centralized tower vs. self-organized peer coordination
- Communications: continuous broadcast vs. terminal-only (broadcast only during takeoff and landing windows)
- Observation: ADS-B only, camera only, both, or neither (silent-cruise)
Primary metrics: throughput (operations per hour completed without violation), safe separation compliance (what fraction of flight segments maintain required line-of-sight separation), and conflict resolution latency.
Results: where self-organization works
Self-organized coordination with ADS-B broadcast matches centralized tower throughput up to approximately 20 operations per hour. Below that density, the two authority models are statistically indistinguishable on throughput and separation compliance. Self-org with ADS-B is not a degraded substitute for a tower at low density — it is genuinely equivalent.
Above 20 ops/hour, self-organized coordination degrades. Throughput falls, and more importantly, conflict resolution latency increases — drones spend more time in holding patterns waiting for coordination to resolve. The tower model maintains higher throughput and lower separation violations at high density.
Results: the silent-cruise problem
The most operationally significant finding involves drones that do not broadcast their position — the "silent-cruise" configuration. Silent drones (no ADS-B, no active broadcast) exceed safe line-of-sight separation thresholds at just 12 operations per hour. That is below the density where self-org and tower first diverge. A single silent drone in a mixed fleet is sufficient to create separation violations that the rest of the coordination system cannot compensate for.
The practical implication: ADS-B broadcast is not optional for dense urban air mobility. A regulatory requirement for ADS-B equivalents on all UAM vehicles is not a conservative policy — it is the minimum condition for separation safety above very low traffic densities.
The throughput–safety frontier
We map the Pareto frontier of throughput vs. separation safety across all nine cells. The frontier is dominated by tower + ADS-B at high density and self-org + ADS-B at low density. There is no cell where removing observation (silent-cruise) is anywhere near the frontier. Observation is not a nice-to-have; it is load-bearing for the coordination system.
Companion blog post: Tower vs. self-organized droneport ATC across a 9-cell factorial study.