LiDAR scanners for drones

LiDAR scanners measure distances with laser pulses and generate three-dimensional point clouds of terrain, vegetation and structures. Complete systems also contain an IMU and GNSS to place the points correctly in space.

Returns per pulse

How many returns of one pulse are evaluated. Multiple returns capture ground and vegetation at the same time and are decisive for forest surveys.

Accuracy (cm)

Manufacturer figure in centimetres, but defined differently: system accuracy, ranging accuracy or precision (repeatability). The meaning is given in the note for each row; only compare like with like.

Weight (g)

Weight of the scanner or system. It determines which drone class can carry the payload and how long the flight lasts.

IMU and GNSS integrated

True for complete survey systems with their own IMU and GNSS. Bare scanners without these parts need an external position and attitude solution to deliver georeferenced point clouds.

Point rate (per s)

Measurement points per second. For YellowScan it is the number of laser pulses (shots), not points; several returns per pulse produce more points.

Range (m)

Maximum measuring distance according to the manufacturer, usually for highly reflective targets. On dark surfaces the range is shorter; check the reference reflectivity in the datasheet.

Field of view

Angular range covered, sometimes with scan pattern (line, repetitive, non-repetitive). A wide field of view covers a large area per flight line; a line scan gives more uniform point density.

Wavelength (nm)

Laser wavelength in nanometres. It affects the eye-safety class, range and behaviour on water and vegetation; green lasers are used for bathymetric surveys.

For forest surveys, multiple returns per pulse are decisive because they capture ground and canopy at the same time. Point rate, field of view and range determine how much area is covered per flight and at what point density. Complete systems with integrated IMU and GNSS deliver georeferenced data; bare scanners need an external solution for that. Accuracy figures are defined inconsistently and are only comparable like for like. Weight decides the required drone class and the flight time.

Accuracy figures are mixed (system accuracy, ranging accuracy or precision); the meaning is given in the note for each row.

For YellowScan the point rate is the number of laser pulses; for the DJI L3 only the pulse frequency is given.

LiDAR devices are laser products; observe the laser class stated by the manufacturer.

Why do multiple returns matter?

A pulse can return from leaves, branches and the ground. Evaluating several returns reveals the ground even under vegetation.

What is the difference between accuracy and precision?

Accuracy describes the deviation from the true value, precision the spread of repeated measurements.

Do I need RTK for LiDAR?

Georeferenced, survey-grade point clouds need a precise position and attitude solution, usually with RTK or post-processing.