Modern drones now come with obstacle avoidance systems, designed to prevent crashes into objects and people. While not foolproof, this feature is a critical safety net—particularly in advanced models like those from DJI and Autel. These systems use a combination of vision sensors and, in some cases, LiDAR to detect and react to their surroundings.
How Obstacle Avoidance Works
The core idea is simple: sensors detect obstacles, and the drone adjusts its flight path accordingly. Most drones use a combination of six vision sensors (front, rear, bottom) and a downward-facing infrared sensor, effective from roughly 20 inches up to 98 feet. These sensors alert the pilot via the drone’s app—visual warnings, distance indicators, and audio alerts.
Some newer drones feature LiDAR, emitting lasers to map the environment, especially useful in low-light conditions where cameras struggle. LiDAR works best for forward-facing detection, complementing the 360-degree vision systems found in higher-end DJI models. The most popular current DJI models offering Obstacle Avoidance are the DJI Mavic 4 Pro, DJI Air 3S, DJI Air 3, DJI Mini 4 Pro and the DJI Mavic 3 Series.
Settings and Behavior: Brake, Bypass, and Off
Drone manufacturers like DJI offer different modes for obstacle avoidance. The most common are:
- Brake: The drone stops when an obstacle is detected.
- Bypass (Normal): The drone flies around the obstacle at a safe distance.
- Bypass (Nifty): More aggressive adjustments, potentially increasing collision risk.
It’s also possible to disable the system entirely, which is sometimes necessary in complex environments where the sensors interfere with smooth flight or video capture.
Why It’s Useful, But Not a Replacement for Skill
Obstacle avoidance is a powerful safety net. It can save a drone from crashes due to pilot error, improve subject tracking, and make “Return to Home” safer. However, it should never be relied on as a substitute for pilot awareness. The sensors aren’t perfect; they can fail in bright or dark light, and they don’t always detect thin objects like wires or snow.
Obstacle Avoidance should only be used as a failsafe after your judgment when flying close to obstacles.
The Trade-Offs: Smoothness vs. Safety
While obstacle avoidance enhances safety, it can also compromise flight smoothness. In tight spaces like forests, the system might make abrupt corrections that ruin footage. In these cases, turning it off and flying carefully is often the better option.
LiDAR: A Boost in Low Light
LiDAR enhances obstacle detection in low-light scenarios. It can identify objects up to 82 feet away, but it struggles with thin or transparent obstacles like wires and glass. The drone automatically switches between LiDAR and vision sensing based on conditions, sometimes using both simultaneously.
In conclusion: Drone obstacle avoidance is a significant advancement in flight safety. While not infallible, it provides an extra layer of protection, especially when combined with skilled piloting and situational awareness.
