This article explains how Cortex determines its position during flight, the methods it uses, and how it transitions between them when conditions change.
How Cortex determines position
During flight, Cortex must know where it is in order to maintain control, autonomy, and scan quality.
Cortex continuously evaluates available sensor data and signal quality to determine its position. It primarily relies on SLAM, but can automatically transition to alternative methods when SLAM performance degrades.
This behavior allows the system to adapt to changing environments without requiring user input.
Using SLAM
SLAM is the primary method Cortex uses to determine its position. It relies on LiDAR data to identify environmental features and build a map while estimating position in real time.
SLAM provides the highest accuracy and stability and is required for full autonomous operation.
Using GPS and INS
When Cortex can no longer determine its position reliably using SLAM, it may transition to alternative methods depending on signal availability.
• GPS is used when SLAM is lost and a reliable GPS signal is available.
• INS is used when both SLAM and GPS are unavailable and relies on IMU data to estimate movement.
Both GPS and INS represent degraded states and are intended for short-term use only.
Why it matters
The ability to accurately determine position directly affects flight safety, autonomy, and scan reliability.
Understanding how Cortex transitions between methods helps operators recognize degraded states and respond appropriately during a mission, reducing the risk of unsafe flight conditions.
• Automatic method selection: Cortex selects the most appropriate method without user input.
• Graceful degradation: Allows controlled behavior when SLAM performance degrades.
• Improved safety outcomes: Prevents continued autonomous flight when position accuracy is reduced.
• Operator awareness: Clear system behavior supports informed decision-making.
How it works
During flight, Cortex continuously monitors SLAM quality and signal availability.
SLAM is used as the primary method to determine position.
If SLAM is lost and GPS is available, Cortex uses GPS to continue determining position.
If both SLAM and GPS are unavailable, Cortex falls back to INS.
If SLAM quality degrades significantly during an autonomous mission, Cortex will initiate a Return To Home to prevent further map degradation.
Common Scenarios
In environments where conditions are good for SLAM and GPS such as outdoor sites or surface operations with strong features, Cortex uses SLAM as the primary method to determine position, with GPS and INS available as fallbacks.
In fully enclosed or underground environments where GPS is unavailable but features are sufficient, Cortex relies on SLAM to determine position, with INS available as the only fallback if SLAM is lost.
In low-feature environments or large open areas where SLAM performance is reduced but GPS is available, Cortex uses GPS as a fallback method to determine position, with INS available as a secondary fallback.
In environments with minimal geometric features and no GPS coverage, such as smooth shafts, tunnels, or enclosed spaces with minimal geometric variation, Cortex relies solely on INS as a fallback method.
Best Practices
Understanding how Cortex determines position helps operators respond correctly when conditions change during flight.
Do | Don't |
|---|---|
Monitor system state during flight. | Rely on INS for extended duration. |
Attempt to recover SLAM as soon as possible if it is lost. | Assume degraded methods provide the same accuracy as SLAM. |
Be prepared to take manual control or land when operating in a degraded state. | Ignore system warnings related to degraded position accuracy. |
INS is prone to accumulating error and only works until SLAM is recovered.
If SLAM is not recovered within approximately 10 seconds, attempting to continue hovering may result in a crash due to accumulated INS error. In this situation, an emergency landing should be attempted immediately.