Guardians that see first and keep clear.
Drones on watch posts around a station extend its sensors, give the crew and the command center time to decide, keep themselves clear of intruders, and survive jamming and GNSS spoofing. Decisions are split by time budget: the drone acts alone within seconds, the station within its delegated authority, and the center decides everything beyond protection.
Four designs against eight threats
Guardians kept clear of every threat
Median warning before arrival
Cells are shaded by value in one hue; hover or focus a cell for the 10th to 90th percentile. "—" means the measure does not apply (no approaching threat). Station only: the station's ground sensor alone. Onboard only: drones sense and protect themselves, no network. Networked: drone sensing fused at the station, which gives every order. Hybrid (proposed): networked plus onboard reflexes, lost-link procedures and a navigation cross-check.
What else changed with the design
Moving the posts: the layout experiment (hybrid)
The fast inbound object reaches the station in seconds; no decision logic saves a drone hovering over the impact point. Offsetting it does.
Replay any simulated run
Who decided what
Seed 0 of the selected scenario and design. Onboard acts in under a second, the station within seconds, the center after its link delay and an operator's decision.
The same logic on real PX4: eight flights
Three PX4 instances hold watch posts around the carrier while each flight adds its own threats, a jammer, a GNSS spoofer or a dead link to the center. The station and each guardian run the same decision code as the simulator above; separations, drift and landings are measured on Gazebo truth.