07Aerial robots, swarms & dual use
How to keep a robot fleet operating through communication and positioning failures
What keeps working, what degrades and when the mission must stop if GNSS, links or a fleet node fail. Every figure links to its source; where there is no sufficient public evidence, we say so.
Last reviewed: 2026-11Methodology & sources →
01 · The operational problem
“I need to inspect a facility even where coverage or positioning is unreliable”
Tunnels, mines, boiler interiors, substations and solar plants spanning hundreds of hectares share one problem: GNSS and radio are not guaranteed. GNSS interference is already documented by aviation authorities in several European regions.[EASA, 2026]
Operating envelope for each failure
No technique makes a fleet “work when everything fails”. What you can design is what the system does on each failure. This logic should be written into the operating procedure and the authorisation.
GNSS loss or spoofing
- The mission continues if…
- A validated alternative localization source exists (VIO, LiDAR, beacons) and the environment is within its envelope (light, texture, geometry).
- It degrades…
- Position uncertainty grows with distance: reduce speed and range and prioritise the return.
- It must stop when…
- There is no alternative source, or uncertainty exceeds the margin to obstacles or the authorised geofence.
Loss of the command link (C2)
- The mission continues if…
- The authorised lost-link procedure allows completing the pre-programmed task; data is stored onboard.
- It degrades…
- No live video or re-tasking: the operator loses the ability to intervene.
- It must stop when…
- As set by the contingency procedure: return to launch, to the dock, or a safe landing.
Network partition or leader loss
- The mission continues if…
- The group that keeps a majority of nodes can elect a new leader and reassign tasks.
- It degrades…
- The minority group cannot elect a leader: it keeps already-assigned tasks that are safe without coordination.
- It must stop when…
- A task requires coordination (several robots in the same volume, for example): the minority group suspends it.
Perception degradation (darkness, fog, dust)
- The mission continues if…
- Another sensor covers the condition: LiDAR in darkness, thermal in low light, or onboard lighting.
- It degrades…
- Obstacle avoidance and visual localization lose reliability: increase safety distances.
- It must stop when…
- No onboard sensor ensures obstacle detection in the current condition.
02 · Decision table
What to evaluate, what to ask the vendor and what to measure in the pilot
Start from the need, not the technology. For each typical need, this table summarises the evaluation criteria, the questions to ask the vendor and the metrics that belong in the pilot's acceptance criteria.
Indoor and confined-space inspection
What to evaluate
- GNSS-free localization (LiDAR, VIO)
- Onboard lighting and darkness sensors
- Collision and obstacle tolerance
- Recovery after link loss
Questions for the vendor
- Localization results in an environment equivalent to ours?
- What does the system do if it loses localization mid-gallery?
- What is the real endurance with the payload we need?
What to measure in the pilot
- Position error against surveyed control points
- Share of surface with valid data
- Pilot interventions per flight
- Inspection time vs. current method
Fleets over large sites
What to evaluate
- Actual coordination level (central, distributed or swarm)
- Communications coverage across the site
- Battery and dock management
- Supervision: robots per operator
Questions for the vendor
- Who decides task allocation and what happens if that element fails?
- What data do robots share with each other and how often?
- What regulatory authorisation do similar operations hold?
What to measure in the pilot
- Hectares inspected per hour and per operator
- Valid vs. planned coverage
- Time to reassign a failed robot's task
- Confirmed findings vs. false positives
Continuity under disconnection
What to evaluate
- Which tasks are safe without a link and which are suspended
- Onboard storage and forwarding when contact returns
- Authorised contingency procedures
- Behavior under network partition
Questions for the vendor
- Can we see a demonstration with an induced link loss?
- What happens if the fleet splits into two groups without contact?
- How is what happened during disconnection logged?
What to measure in the pilot
- Missions completed with induced disconnection
- Data recovered vs. captured
- Reconnection and sync time
- Incidents and geofence deviations
Economic viability
What to evaluate
- Actual uptime (system availability)
- Data quality for the decision being made
- Maintenance, batteries and replacement
- Cost per mission and per useful finding
Questions for the vendor
- What is the measured availability at customers with similar use?
- What does the subscription include and what is extra?
- What is the service life of batteries and sensors?
What to measure in the pilot
- Cost per mission vs. current method
- System availability (%)
- Maintenance hours per operating hour
- Findings that lead to a maintenance action
03 · Coordination levels
Not every group of drones is a swarm
The difference is not how many robots fly, but who decides and what information they share. Each level behaves differently under the same failure.
- 1
Independent drones
- Who decides
- Each operator or drone, separately
- What they share
- Nothing between drones; only telemetry with its operator
- If a node or link fails
- Its area stays uncovered until a person reassigns it.
Maturity and example
Common practice in inspection.
- 2
Fleet coordinated by a controller
- Who decides
- A central planner (station, cloud or fleet software)
- What they share
- State, position, battery and progress with the controller
- If a node or link fails
- If the controller or link fails, each drone finishes its sector or returns; reassignment stops.
Maturity and example
Authorised commercial operation: multi-drone solar inspection with software-assigned sectors, and remote BVLOS docks.[vHive, 2025][Skydio]
- 3
Distributed coordination
- Who decides
- The robots themselves, via rules or consensus (leader election, auctions)
- What they share
- State, tasks and coverage map, peer-to-peer over a mesh
- If a node or link fails
- The others reassign the failed node's task if they keep quorum; an isolated minority group cannot.
Maturity and example
Mature techniques in distributed systems and ad-hoc networks; we found no documented civil inspection operation with this architecture.[USENIX ATC, 2014][IETF, 2014]
No documented civil operation
- 4
Cooperating swarm
- Who decides
- Collective behavior emerging from each robot's local rules
- What they share
- Detections and partial maps that change neighbors' actions (confirm a finding, fill a gap)
- If a node or link fails
- Designed to degrade gradually as robots are lost, though its behavior is hard to verify and certify.
Maturity and example
Mainly research; the reference literature points out limits to real-world application.[Swarm Intelligence, 2013]
No documented civil operation
04 · Where Physical AI acts
Perceive, reason, decide and act — on each robot and across the fleet
What turns a drone fleet into a Physical AI system is that it closes the loop between what it perceives and what it does, without waiting for a human at every step. That loop exists at two scales, and each degrades differently.
| Stage | On each robot | Across the fleet |
|---|---|---|
| 1Perceive | Detect obstacles and anomalies (thermal, visible, LiDAR) with models running onboard.[Skydio, 2023] | Fuse detections from several robots into a shared map. |
| 2Reason | Estimate its own position and uncertainty, and judge whether a detection is reliable. | Prioritise which findings to confirm and which coverage gaps to fill. |
| 3Decide | Replan the route, slow down or return. | Reassign tasks by position, battery and sensors. |
| 4Act | Execute flight or locomotion control. | Dispatch new tasks and create work orders. |
Example on a solar plant
- 1A drone detects a panel with an abnormal temperature in its thermal image.
- 2It estimates the finding's position and confidence and shares it with the fleet.
- 3The system sends the nearest drone with a higher-resolution camera to confirm it, without interrupting everyone else's coverage.
- 4If confirmed, a work order is created with the location and images.
If the network goes down, each drone keeps its local loop (navigate, avoid obstacles, log findings) and the fleet loop is suspended until contact returns.
05 · Simulator
Try the failures in a teaching model
The simulator shows the coordination logic of an inspection fleet under interference, leader loss and network partition. It is a simplified teaching model, not a reproduction of real protocols or radio propagation. Its assumptions are listed next to it.
Scenario
No failures. Each drone sweeps its sector and transmits. Three thermal anomalies are hidden in the panels.
Coordination mode
Cooperative swarm. Leaderless mesh: neighbors share tasks through local auctions; any drone with a ground link acts as gateway.
Starts when you reach this section or press Start.
Legend
- Drone with a path to deliver data
- Drone without a path (stores data)
- Safe mode (no quorum)
- Lost drone
- Elected leader
- Ground station (GCS)
- Cell with delivered data
- Cell swept, data on board
- Orphaned sector
- Anomaly detected (?) / confirmed (!)
- Diversion to confirm
- Interference zone · Links blocked (partition)
Event log
Perception → reasoning → decision → action, plus network events.
- No events yet.
What happened and why
The explanation appears when the run ends. You can speed up with ×4.
Same failure, four ways to coordinate · Normal operation
Each row is a complete, deterministic run of the selected scenario, up to 180 simulated seconds, with the same rules and seed. The highlighted row is the one on screen.
Independent routes
- Final valid coverage
- 100%
- Mission time
- 42.6 s
- Orphaned sectors at the end
- —
- Reallocation after failure
- —
- Confirmed anomalies
- 0/3 · 3 to manual review
- Detection → confirmation
- —
- Data held on board (peak)
- 0%
Central controller
- Final valid coverage
- 100%
- Mission time
- 53 s
- Orphaned sectors at the end
- —
- Reallocation after failure
- —
- Confirmed anomalies
- 3/3
- Detection → confirmation
- 5 s
- Data held on board (peak)
- 0%
Distributed coordination
- Final valid coverage
- 100%
- Mission time
- 53 s
- Orphaned sectors at the end
- —
- Reallocation after failure
- —
- Confirmed anomalies
- 3/3
- Detection → confirmation
- 5 s
- Data held on board (peak)
- 0%
Cooperative swarm● On screen
- Final valid coverage
- 100%
- Mission time
- 53 s
- Orphaned sectors at the end
- —
- Reallocation after failure
- —
- Confirmed anomalies
- 3/3
- Detection → confirmation
- 5 s
- Data held on board (peak)
- 0%
Times in simulated seconds, not real time. “—”: not applicable in this scenario. If you move the interference zone, the on-screen run diverges from this table.
Model assumptions
What this simulation represents and what it leaves out. Read this before drawing conclusions from the numbers.
- Nature
- Deterministic didactic model (fixed seed, 0.05 s step). It does not reproduce real protocols, radio propagation or flight dynamics, and it is not from an experiment. Its purpose is to compare coordination logics under the same rules.
- Connectivity
- Share of operational drones with a path to deliver data. Independent and central: direct link to the station. Distributed: one- or multi-hop mesh path to the leader. Swarm: mesh path to any drone with a ground link.
- Coverage
- We separate area swept (cell overflown) from valid coverage (its data reached the station). A drone without a path stores data on board and forwards it when it reconnects; once its task is done, it heads toward the station to deliver.
- Links & interference
- Link quality falls with the square of distance (mesh range 300 u., station 900 u.). Interference is a simplified factor: full strength in the inner 60 % of the zone, fading to the edge. Frequency hopping reduces it to 45 %. There is no radio physics.
- Leadership
- Raft-like election: each drone has a random timeout (1.5–3 s). When it expires without hearing from the leader, the drone runs as candidate and wins if its connected component holds a majority: 8 of the 14 configured members, failed ones included. A leader that loses the majority for 2 s steps down.
- No quorum
- A minority cannot elect a leader. It enters safe mode: it finishes its already-assigned task, stores data, accepts no new tasks and waits. This prevents two leaders, at the cost of not reacting to the unexpected.
- Reallocation
- A lost drone is detected after 3 s without heartbeats. The station reallocates in central mode, the leader in distributed mode, and neighbors after a 0.6 s auction in swarm mode. The lowest-cost drone wins: distance × (1 + 0.5 × pending tasks). The sector is redone in full.
- Physical AI loop
- Perception: when flying over a hot spot, a drone detects it with a fixed confidence (64–78 %). Reasoning: below 90 %, a second pass by another drone is required. Decision: the coordinator picks the lowest-cost drone. Action: that drone diverts, confirms (≥ 96 %) and returns to its lane. Without coordination, the anomaly is left for manual review.
- Out of scope
- Wind, battery physics and endurance, collisions and separation, real radio propagation, network latency, sensor errors, regulation (BVLOS, U-space) and security. The figures are not performance predictions for any real system.
06 · GNSS-denied navigation
Without satellites, the robot has to estimate its own position
Every localization source has an envelope: conditions where it works and conditions where it fails. Published figures come from benchmarks with specific hardware and environments; they are not performance guarantees at your facility.
Localization sources compared
GNSS / RTK
Low- Published accuracy
- ~4.9 m (smartphone, open sky) · 1 cm + 1 ppm horizontal with fixed RTK (DJI M350 RTK sheet)[GPS.gov][Norsat][EASA, 2026]
- Drift behavior
- No drift accumulation while the signal is valid
- Where it fails
- Jamming and spoofing, indoors, tunnels, dense urban areas and under foliage
Inertial only (IMU)
Low- Published accuracy
- No absolute accuracy: error grows with time squared (accelerometer bias) or cubed (gyro bias)[Inside GNSS]
- Drift behavior
- Fast without external aiding
- Where it fails
- Any long mission without another source to bound the error
Visual-inertial odometry (VIO)
Medium- Published accuracy
- Expressed as % of distance traveled; varies widely by algorithm, onboard computer and environment[IEEE ICRA, 2018][ETH Zürich, 2016]No verifiable general range
- Drift behavior
- Grows with distance; loop closure reduces it at the cost of more compute
- Where it fails
- Low texture, darkness, fog, very fast motion and reflective surfaces
LiDAR SLAM
High- Published accuracy
- ~0.5% translational error for top KITTI entries (ground vehicle outdoors)[KITTI]
- Drift behavior
- Low; reduced further with loop closure or a prior map
- Where it fails
- Poor geometry (long uniform galleries), dense dust or rain; adds weight and power draw
Visual localization against satellite maps
High- Published accuracy
- Absolute; depends on altitude, terrain texture, season and map age[arXiv, 2025][arXiv, 2021]No verifiable general range
- Drift behavior
- No drift accumulation when matching succeeds
- Where it fails
- Outdated maps, clouds, night without thermal, uniform terrain (water, desert) and indoors
Terrain-referenced navigation (TERCOM-style)
Low- Published accuracy
- Limited by relief-map quality and by the terrain itself[USPTO]No verifiable general range
- Drift behavior
- Absolute over terrain with relief
- Where it fails
- Flat terrain; needs an altimeter and an onboard digital elevation model
UWB beacons
Low- Published accuracy
- ~10 cm with line of sight and calibration[NiceRF]
- Drift behavior
- No drift accumulation within coverage
- Where it fails
- Needs installed infrastructure; multipath and poor anchor geometry
Figures depend on hardware, calibration, altitude, light and environment. Ask vendors for results under conditions equivalent to yours.
Position-estimate drift in a GNSS-denied gallery
A loop of about 520 m. Move the time slider to see how each estimate separates from the true path.
- True path
- IMU only (dead reckoning)49.3 m
- VIO7.3 m
- VIO + loop closure0.7 m
Model assumptions
- Commercial-grade IMU with constant bias: error grows non-linearly with time (integrator physics, not data from a specific unit).
- VIO with an assumed drift of 1.5% of distance traveled. An illustrative value, not a measured result.
- Loop closure when revisiting known areas, pulling the estimate back near the true path.
- No occlusions, no dust and enough texture: in real conditions, VIO can fail entirely.
Teaching model with editorial assumptions (evidence level D). It shows the shape of drift; do not use it to size a system.
07 · Resilient communications
Three layers that reduce the impact of a failure, each with its limits
Communication resilience combines the spectrum, the network topology and the decision logic. No layer removes the risk on its own: know what each one protects against and where it stops helping.
- L1 · ESPECTRO
Spectrum: frequency hopping and selection
The link changes channel following a shared sequence and avoids bands where it detects noise.
Protects against
- Narrowband interference
- Momentary congestion of a channel
Limits
- Does not protect against interference covering all usable bands
- Available bands depend on national regulation
- L2 · MANET
Topology: multi-hop ad-hoc network
Every robot also acts as a relay. Standardised routing protocols such as OLSRv2 recompute routes when a link drops; data can be stored onboard and forwarded when contact returns.[IETF, 2014][IETF, 2022]
Protects against
- Loss of individual links
- Robots beyond the station's direct range
Limits
- Reduces single points of failure but does not remove them: if a bridge node fails, the network splits
- Recovery time depends on the control-message configuration
- Store-and-forward does not guarantee delivery
- L3 · CONSENSO
Decision: leader and tasks by consensus
With consensus algorithms such as Raft, a candidate needs a majority of votes to become leader. If the network splits, the minority group cannot elect a leader: a deliberate safety limit that prevents two leaders issuing contradictory orders.[USENIX ATC, 2014]
Protects against
- Leader failure while a majority remains
- Contradictory orders after a partition
Limits
- A partition without a majority halts coordination in that group
- Tasks must be designed to be safe without coordination
08 · Operational lessons & civil maturity
What hostile environments have taught, and what is already proven in civil use
Recent conflicts have accelerated technologies the civil sector can use. We separate two things: the publicly documented lesson and the demonstrated maturity of a specific civil system. Where no civil system has documented operation, we say so.
Key transfer
- Multi-drone coordinationSolar farms & forestsTRL 9
- GNSS-free navigation (VIO/SLAM)Underground mining & tunnelsTRL 9
- Low-latency first-person (FPV) pilotingDisaster search & rescueNo sufficient public evidence
7/7 technologies
Multi-drone coordination
★ Key transfer: Solar farms & forestsSeveral drones sharing a mission, with task allocation and reassignment on failure.
USASolar farms & forestsAgricultural monitoringDisaster search & rescueDemonstrated civil maturity
Demonstrated civil maturity: TRL 9Multi-drone solar inspection with software-assigned sectors (vHive, FAA waiver, 2025). This is central coordination, not a decentralised swarm.[vHive, 2025]
Decentralised swarms in civil inspection: we found no documented operation.
GNSS-free navigation (VIO/SLAM)
★ Key transfer: Underground mining & tunnelsEstimating position from cameras, IMU and LiDAR when satellites are unavailable or unreliable.
RussiaUnderground mining & tunnelsCritical infrastructureDemonstrated civil maturity
Demonstrated civil maturity: TRL 9LiDAR SLAM drone in a coal mine (Elios 3 at LW Bogdanka), documented in a technical publication.[E3S Web of Conferences, 2024]
Low-latency first-person (FPV) piloting
★ Key transfer: Disaster search & rescueAgile manual control with low-latency video to maneuver in complex spaces.
UkraineDisaster search & rescueCritical infrastructureUnderground mining & tunnelsDemonstrated civil maturity
Demonstrated civil maturity: TRL 9Assisted piloting in confined spaces with a caged drone (Elios 3 in a mine).[E3S Web of Conferences, 2024]
FPV use in search and rescue: we found no public evaluation of results.
Fiber-optic control links
The drone receives commands over an unspooling fiber cable: it emits no radio and is unaffected by jamming.
UkraineRussiaUnderground mining & tunnelsCritical infrastructureDemonstrated civil maturity
No sufficient public evidenceWe found no documented civil deployments with unspooling fiber. Tethered drones are a different technology.
Visual localization against maps
Matching the camera image against onboard satellite maps to obtain an absolute position without GNSS.
RussiaAgricultural monitoringDisaster search & rescueLong-range logisticsDemonstrated civil maturity
No sufficient public evidenceRecent literature is mostly research prototypes; we found no documented civil operation.
Mass production and fast iteration cycles
Simple designs built in volume with commercial components and frequently updated software.
IranUSALong-range logisticsAgricultural monitoringCritical infrastructureDemonstrated civil maturity
Demonstrated civil maturity: TRL 9Civil autonomous operation at scale: medical and retail logistics with over 2 million deliveries (Zipline, company figures). It does not derive from these programs.[DroneLife, 2026]
Docked drones and remote BVLOS operation
Autonomous stations that launch, recharge and recover the drone, operated remotely.
USAPerimeter securityCritical infrastructureDisaster search & rescueDemonstrated civil maturity
Demonstrated civil maturity: TRL 9BVLOS docks at dozens of a utility's facilities (Skydio with Dominion Energy, 2022, per the manufacturer).[Skydio]
TRL is assigned to a specific system, not to a technology category, using NASA's scale (9 = actual system proven through successful operations). The assignment is ours, based on the cited evidence.[NASA]
High-level analysis from public sources, focused on civil applications. It contains no operational or employment detail.
09 · Regulatory framework (EU)
Which regulatory route applies to your operation
In the EU, an operation's category depends on its risk. Most professional BVLOS inspections fall into the specific category, which has several access routes with different requirements.
- UE 2019/947
Three risk-based categories
Open: low risk, with height, weight and visual-line-of-sight (VLOS) limits; no prior authorisation. Specific: higher-risk operations, such as most professional BVLOS. Certified: risk comparable to crewed aviation (e.g., carrying people).[EUR-Lex, 2019]
- STS
Standard scenario: declaration
If the operation fits an EASA standard scenario (STS-01 and STS-02), a declaration to the authority is enough, with no prior authorisation. The scenario's conditions and the matching equipment class are required.[EASA][Transpordiamet]
- PDRA · SORA
Authorisation: PDRA or SORA
If it does not fit an STS, an authorisation is requested. A PDRA is a scenario already assessed by EASA with defined mitigations, simplifying the application. If no PDRA fits either, a full SORA risk assessment is done; its risk level drives the link, containment and contingency-procedure requirements.[EASA]
- LUC
LUC certificate: self-approval
The light UAS operator certificate (LUC) lets an organisation with a mature management system approve its own operations within the granted privileges. It is the route to scale many operations without requesting an authorisation for each one.[EASA][Luftfartstilsynet]
- UE 2021/664
U-space
Framework to designate U-space airspace with digital services for drones, such as network identification, geo-awareness and flight authorisation. Its rollout depends on each state designating such airspace.[EUR-Lex, 2021]
- UE 2024/1689
AI Act and aviation
For civil aviation, the AI Act acts mainly through EASA rules: aviation acts on AI systems that are safety components must take the high-risk requirements into account. Exclusively military systems are outside its scope.[EASA, 2024][SpringLex]
- UE 2021/821
Dual-use exports
Items on the Annex I list need a licence for export outside the EU. Check the classification of navigation, communications and encryption hardware and software before selling or transferring.[EUR-Lex, 2021]
Informational summary as of November 2026; not legal advice. Always check the consolidated text and your national authority.
10 · Platforms
Aerial platforms related to these applications
Open a sheet to see specifications with their conditions and sources.
- Drone / aerial robot (UAV)Dual use
X10
Skydio
Drone with vision-based autonomous navigation, able to fly at night with visible or infrared illumination (NightSense). It can operate from a dock for remote missions; the X10D variant is dual-use.
- Autonomy
- L4
- Max. runtime
- 40 min
- Max. payload
- 0.34 kg
Manufacturer maxima; not simultaneous.
Open sheet → - Drone / aerial robot (UAV)
Matrice 350 RTK
DJI
Enterprise platform for interchangeable payloads: thermal cameras, aerial LiDAR and speakers, up to three at once. It flies RTK GNSS waypoint missions and withstands winds up to 12 m/s.
- Autonomy
- L2
- Max. runtime
- 55 min
- Max. payload
- 2.7 kg
Manufacturer maxima; not simultaneous.
Open sheet → - Drone / aerial robot (UAV)
Elios 3
Flyability
Collision-tolerant caged drone with LiDAR for real-time GPS-denied SLAM. It inspects boilers, tanks, sewers and mine galleries and builds 3D models in flight.
- Autonomy
- L2
- Max. runtime
- 12 min
- Max. payload
- 0.3 kg
Manufacturer maxima; not simultaneous.
Open sheet → - Drone / aerial robot (UAV)
Zip (Platform 1)
Zipline
Fixed-wing aircraft for long-range medical logistics, catapult-launched with parachute drops. It underpins the national medical distribution networks in Rwanda and Ghana.
- Autonomy
- L4
- Max. runtime
- 110 min
- Max. payload
- 1.8 kg
Manufacturer maxima; not simultaneous.
Open sheet → - Drone / aerial robot (UAV)Dual use
Vector
Quantum Systems
Dual-use fixed-wing eVTOL for long-range reconnaissance and mapping. It takes off vertically and cruises efficiently for up to 3 h. In 2026 the US Army selected the Vector AI variant for brigade-level reconnaissance.
- Autonomy
- L3
- Max. runtime
- 3 h
- Max. payload
- 1.2 kg
Manufacturer maxima; not simultaneous.
Open sheet →
Dual-use ground platforms (e.g., THeMIS or Vision 60) are in the explorer, under ground vehicles and quadrupeds. See ground platforms →