LiDAR offers a vast improvement over traditional surveying techniques and will lead a fundamental change in how the majority of surveying is undertaken. UAV LiDAR 3D mapping uses lasers to accurately measure the range from the sensor to points on an object or on the ground. Using multiple lasers at high speed allows a huge amount of data to be collected very quickly. UAVs enable the ability to operate LiDAR lower and slower, therefore producing data 100 times denser and up to 10 times more accurate than systems carried by planes and helicopters.
UAV LiDAR is an airborne version of terrestrial laser scanning, being airborne it is able to rapidly scan large or complex areas. Collecting 700,000 points per second with an average surface density of >700 points per square meter. Using data from a highly accurate on-board IMU to measure the attitude of the aircraft when each point is collected, as well as an RTK GPS system, an extremely detailed 3D map can be created of any object or area. Post process correlation of IMU and GPS data, can then geo-reference this data to an accuracy of a few millimetres.
LiDAR scanning is the perfect accompaniment to photogrammetry, perfect for applications when photogrammetry is less suited, for instance LiDAR has the ability to penetrate vegetation to create accurate digital terrain models through dense forests or for power line surveys to measure line ‘sag’ and vegetation proximity.