Agras T40 Obstacle Avoidance with Radar and Vision

Farm drones rarely fly over flat, empty land. Trees, power poles, irrigation equipment and slopes directly affect flight safety. The Agras T40 combines an active phased array radar with a binocular (stereo) vision system to reduce these risks. Here is what they do in the field, and their limits.

Note: The Agras T40 is a previous-generation DJI spraying drone. The current line-up includes the Agras T50, Agras T55 and Agras T70P. The information here remains relevant for operators still flying the T40.

What Is Active Phased Array Radar?

Conventional radars rotate their beam mechanically; phased array radar steers it electronically, which makes scanning faster and more flexible. The T40's radar scans its surroundings in about 0.1 seconds, can focus its beam as needed and detects obstacles up to 20 m away.

The radar's focus changes with the flight: on slopes it looks at the ground to keep a constant height over the crop; in level flight it looks ahead for obstacles.

Stereo Vision

Front and rear camera pairs perceive depth like human eyes and build a 3D point cloud of the surroundings, helping the drone find its way past multiple obstacles.

How Radar and Vision Work Together

Data from both systems are fused into one environment model. Radar is less affected by dust and spray mist; cameras add shape and position detail. On an automatic route, the T40 can stop at or fly around an obstacle.

Benefits in the Field

• Constant height on slopes: terrain following helps even coverage on hillsides and terraces.
• Tree-lined edges: automatic braking or avoidance near trees and poles.
• Low light: radar works regardless of light, so obstacle sensing continues at dusk.

Limits and the Pilot's Role

No sensing system replaces an attentive pilot. Thin power lines, guy wires and fine branches may not always be detected. Therefore:

• Always mark power lines as obstacles on the map.
• Clean the radar surface at the end of each day; mud and residue weaken detection.
• Keep the drone in line of sight and be ready to intervene.

See our T40 mapping article on marking obstacles correctly.

Obstacle Sensing on Current Models

The current Agras T50 takes this further with dual phased array radars and dual stereo vision. See all models on our spraying drones page.