DFN Defence navigates by matching the onboard camera to reference maps — drift-free, fully passive, day and night. When GNSS is jammed or spoofed, the platform still knows exactly where it is.
Contested areas are routinely GNSS-denied. A jammed receiver gives nothing; a spoofed one gives a confident wrong answer — worse than none.
Inertial-only and optical-flow navigation accumulate error. Over a long transit the platform arrives hundreds of metres off the intended point.
Active rangefinders and RF aids radiate. In a contested zone, emitting is being located — navigation should stay silent.
Military-grade inertial units are accurate but bulky, costly and export-restricted — unfit for attritable, low-cost platforms at scale.
Matches live imagery to reference satellite maps for drift-free absolute geolocation — resets error on every fix.
Tracks motion between map fixes with high-rate visual and inertial odometry for smooth, continuous position.
Fuses camera, IMU and airspeed into one robust estimate that degrades gracefully when any input weakens.
Works across visible and thermal (LWIR) imagery, and tolerates seasonal, lighting and terrain change.
Receives only — no RF, no laser, no GNSS. Nothing radiates, so nothing reveals the platform.
Outputs a standard position stream to PX4, ArduPilot and custom stacks — rotary, fixed-wing and VTOL.
Each classic technique fails somewhere. DFN combines them so a weakness in one is covered by the others.
| Method | Strength | Where it fails |
|---|---|---|
| Optical flow | Cheap, fast | Drifts; weak at altitude; often needs an emitting altimeter |
| Visual-inertial odometry | Lower drift than flow | Scale errors; no absolute position; drift grows over distance |
| SLAM | Accurate locally | No global anchor; compute and memory heavy |
| Map / feature matching | Drift-free, absolute | Lower update rate; gaps where no match is found |
| Military INS | Reliable when denied | Bulky, costly, export-restricted |
| DFN — multi-modal | Absolute + continuous + passive | Map matching anchors, SLAM/inertial bridge the gaps, fusion holds it together |
Comparison reflects general method characteristics; validate against your own operational requirements.
Mission-area satellite maps are loaded to the platform in advance — held on-board, no connection needed in flight.
The camera is matched to the map for absolute fixes; SLAM and inertial carry position smoothly between them.
A standard position stream replaces GPS into the flight stack — and every fix can be signed and logged.
Reference maps and processing stay inside your perimeter. No foreign cloud, no external dependency in the field — deployable fully on-premise or air-gapped.
Each fix can be cryptographically signed and logged — a tamper-evident track of where the platform was and how it knew. Built to sit alongside DFN's signed-video chain of custody.
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