The use of LIDAR UAVs (Unmanned Aerial Vehicles) has become increasingly popular in the topography and mapping industry due to its speed and accuracy. However, to ensure that the data collected is reliable, certain considerations must be taken into account. The average loss of height of the LIDAR of UAVs at the tops of the peaks was found to exceed 0.30 m, and the average relative height loss was observed to be around 49%, compared to a value of 0.03 m and 6% at the bottom of the canopies. This indicates that the loss of LIDAR information from UAVs in the upper part of the canopy has a much greater impact on the accuracy of estimating the structural and functional traits of grasslands than in the lower part of the canopy.
To guarantee reliability of LiDAR data, direct georeferencing is essential, using an accurate GNSS receiver and an inertial measurement unit (IMU) that measures the posture (orientation and positioning) of the LiDAR sensor. Additionally, deploying known and precisely coordinated ground control objectives in GCPs before performing a LiDAR inspection of a UAV ensures that the survey has been correctly executed. Using UAV LiDAR is significantly faster than traditional methods, allowing you to increase your profits. However, since LIDAR sees differently from a typical RGB sensor, it is important to take into account these considerations to ensure that your data is reliable.
With the reduction of information loss in tree crowns, the LIDAR UAV can be used to extract structural and functional features from grasslands with an accuracy comparable to that of the TLS.