GPS-Denied Navigation Techniques
When GPS is unavailable â indoors, underground, in urban canyons, or during jamming â drones must rely on alternative navigation methods. This is critical for military, search-and-rescue, and industrial applications.
GPS-Denied Navigation Challenge
GPS denial can be intentional (jamming/spoofing) or environmental (tunnels, dense forests, indoor spaces). Drones need backup navigation systems that work without satellite signals.
GPS-Denied Techniques Overview
Terrain-Referenced Navigation
Terrain navigation compares measured terrain profile against a stored digital elevation map (DEM) to determine position.
Magnetic Navigation
Earth's magnetic field provides a natural positioning reference. Magnetic navigation compares measured field values against a magnetic anomaly map.
Celestial Navigation
Celestial navigation uses sun, moon, and star positions to determine orientation and approximate position.
Multi-Sensor Fusion for GPS-Denied Navigation
Hands-On Project: Complete GPS-Denied Navigation
Key Takeaways
- VIO provides short-term accurate odometry but drifts over time
- Terrain matching gives bounded-error position fixes outdoors
- Magnetic navigation works in any environment with a magnetic map
- Celestial navigation serves as a backup when other sensors fail
- Multi-sensor fusion provides robust navigation across environments
- Always monitor navigation confidence and have fallback procedures