What is LiDAR?
LiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging) is an optical remote sensing technology capable of measuring the distance to and properties of targets by illuminating them with laser light and analyzing the backscattered light.
LiDAR uses a rapidly pulsed laser rangefinder mounted in light aircraft or ground based vehicle, along with differential GPS and INS (Inertial Navigation System) to locate and orient the vehicle. 10 – 30 thousand XYZ points are surveyed per second with a spatial precision of a few decimeters.
Types of LiDAR:
• Airborne LiDAR Scan: Airborne lidar is when a laser scanner, while attached to an aircraft during flight, creates a 3-D point cloud model of the landscape. This type of lidar is the most suitable source for generating digital elevation models, replacing photogrammetry. One major advantage in comparison with photogrammetry is the ability to filter out reflections from vegetation from the point cloud model to create a digital terrain model which represents ground surfaces such as rivers, paths, cultural heritage sites, etc., which are concealed by trees. Within the category of airborne lidar, there is sometimes a distinction made between high-altitude and low-altitude applications, but the main difference is a reduction in both accuracy and point density of data acquired at higher altitudes. Airborne lidar can also be used to create bathymetric models in shallow water.
• Mobile LiDAR Scan: Mobile LiDAR is the technology that combines multiple sensors. Active sensors, together with Inertial and Global Navigation System, are synchronized on a mobile platform to produce an accurate and precise geospatial 3D point cloud. They allow obtaining a large amount of georeferenced 3D information in a fast and efficient way, which can be used in several applications such as the 3D recording and reconstruction of complex urban areas and/or landscapes. Point density of mobile lidar is significantly higher compared to airborne lidar, making it a more appropriate source for generating highly detailed models for highway, flyovers. This is also widely used to locate overhead wires, light poles, and road signs near roadways or rail lines.
• Static LiDAR Scan: Static lidar is the collection of lidar point clouds from a static location. Typically, the lidar sensor is mounted on a tripod mount and is a fully portable, laser-based ranging and imaging system. These systems can collect lidar point clouds inside buildings as well as exteriors. Common applications for this type of lidar are engineering, mining, surveying, and archaeology