DJI Zenmuse L2

The DJI Zenmuse L2 is a LiDAR payload for heavy multicopters of the Matrice line (Matrice 400, 350 RTK and 300 RTK). It is a complete system with laser scanner, inertial unit (IMU), RTK positioning and a 20 MP mapping camera in 4/3 format, and delivers georeferenced point clouds for surveying and terrain models.

The scanner works at 905 nm and reaches 450 m at 50 % reflectivity and without ambient light (0 klx), at most 500 m; on dark surfaces the range is shorter. The point rate is 240,000 per second with one echo and 1,200,000 per second in multi-echo mode. Up to 5 echoes per pulse capture ground and vegetation at once, which is decisive for forest surveying. The field of view is 70 × 3° in the repetitive line pattern or 70 × 75° in the non-repetitive pattern. Accuracy is quoted as 5 cm horizontal and 4 cm vertical at 150 m. The IMU runs at 200 Hz. The payload weighs 905 g, has an IP54 rating and attaches through SKYPORT.

Laser scanners are laser devices; the laser class given by the manufacturer (standard IEC 60825-1) determines which eye-safety rules apply. The weight counts towards the take-off mass of the aircraft, whose EU class limits are 4 kg (C2) and 25 kg (C3 and C4). Point clouds and images of built-up areas can make people and property recognisable, and then data-protection law applies.

The quality of a point cloud hinges on the trajectory: IMU data and RTK positions are combined with the scanner data in processing. A rigid, low-vibration mount keeps the alignment between scanner and IMU stable. Wear points are the scanner windows, the SKYPORT contacts and the damping; dirt on the window falsifies measurements. Firmware is maintained together with the aircraft.