Sense
Ultrasonic, infrared, stereo vision, LiDAR, and similar sensors turn distance and shape into signals. When they miss or misread, the aircraft is effectively flying blind.
Safe Flying
Drone Obstacle Avoidance Simulator
Pick an avoidance system, terrain, and weather to see how detection range and stopping distance change.
Principles
Avoidance means spotting obstacles early enough within a limited range.
Learn each sensor’s effective range, field of view, common failure modes, and how the flight controller brakes or steers once a threat is detected.
Decide
The flight controller uses distance, relative speed, and a safety buffer to choose: continue, slow down, hover, or detour. Those parameters usually come from manufacturer calibration and physics limits.
Act
Motors and the attitude loop need time to respond. Closing in at high speed, even after “seeing” an obstacle, the stopping distance may still be too short — a common crash cause.
Avoidance Systems
Five common approaches
Select a system to review its range, strengths, and failure conditions.
How to Use
How to run the simulator
Follow these steps.
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Set parameters
Above Flight Sim, choose: avoidance system, terrain, and environment. Use the sliders for airspeed and cruise altitude. Optionally check “Show red detection zone” to visualize the current system’s effective range.
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Start flying
Click “Start Flight Sim.” The drone follows the route automatically. When it detects an obstacle, it may slow, hover, or detour in six directions (left / right / up / down / forward / back).
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Read the results
The right-hand panel shows nearest obstacle distance, effective detection range, environment penalty, and stopping demand in real time. On a collision, status becomes “Simulated crash” — change parameters and hit Reset to try again.
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Adjust the camera
The canvas uses third-person follow. On a trackpad, two-finger swipe rotates and pinch zooms; mouse drag also rotates. The camera stays with the drone so you can review detour paths from the side or above.
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Clear obstacles (optional)
During flight, press Space to fire forward. Some obstacles can be destroyed so you can see whether the route recovers. This is for demonstration only — not a real flight-control feature.
Choosing parameters
- Avoidance system
- Affects detection range, field of view, and how well different obstacles are recognized. Try Ultrasonic vs LiDAR for a clear contrast.
- Terrain
- Changes obstacle types and layout. Sparse Forest has many thin targets; Harbor includes containers, cables, and boats.
- Environment
- Mostly attenuates optical and laser sensors. Fog, rain, and night sharply shorten vision and radar effective range.
- Airspeed
- Higher speed needs a longer stopping distance. Hold other settings fixed and raise speed to see when “can stop in time” becomes “too late.”
- Cruise altitude
- Sets height relative to low obstacles (fences, vehicles, cables). Flying too low triggers more detours or collisions.
Telemetry meanings
- Status
- Current flight behavior: cruise, detour, emergency brake, simulated crash, and more.
- Nearest obstacle
- Distance to the closest forward obstacle; “Not detected” means the system cannot see a target under current conditions.
- Effective range
- Estimated detection distance for this system in the current scene (terrain and weather already applied).
- Env. penalty
- Combined terrain and weather derating factor for the sensor; closer to 1 means more ideal conditions.
- Stopping need
- Estimated safe stopping distance at the current speed. If it exceeds nearest obstacle distance, collision risk rises.
Range and failure modes for each approach are in the Systems section.
Flight SimFlight Sim
Parameters & controls
Choose system, terrain, and weather, set speed and altitude, then press Start.
Detecting an obstacle does not mean you can still stop in time.
Fly the same setup a few times and compare results across speed, terrain, and weather.
Flight Sim