What is LiDAR? | Applications
LiDAR Technology (for Light Detection And Ranging) is a remote sensing technique that uses pulsed lasers to measure distances to Earth. These pulses of light, combined with other data recorded by the system, generate precise three-dimensional information about the shape of the earth or objects and features on its surface.
There are different types of LIDAR depending on the platform where it is integrated, such as airborne, Static and Mobile LIDAR. There is a more detailed classification and it is shown in the following figure:
Terrestrial LIDAR systems can be installed in vehicles, as well as in backpacks for surveying on foot, by bicycle, or by motorcycle. Here the SLAM system has allowed support for georeferencing in closed places. SLAM (Simultaneous Localization and Mapping) is a method used in autonomous vehicles that allows you to create a map and locate the vehicle on that map at the same time. SLAM algorithms allow the vehicle to create maps of unknown environments.
Aerial LIDAR is currently implemented in unmanned aircraft, but there are also projects that require a platform with greater autonomy such as a manned helicopter or plane, everything will depend on the dimensions of the study area.
Advantages and Disadvantages of LiDAR Technology
LIDAR Technology has a good number of advantages such as obtaining terrain information in areas with very dense vegetation. Let’s remember that we cannot perform standard photogrammetry in areas such as the jungle because the treetops and vegetation will be identified as the terrain surface.
LIDAR is also a very accurate laser system as it has more supporting sensors such as IMUs (an Inertial Measurement Unit or IMU, is an electronic device that measures and reports an aircraft’s speed, orientation, and gravitational forces, using a combination of accelerometers and gyroscopes.). Similarly, the point cloud is generated very quickly compared to photogrammetric correlation techniques. We can say that we require less post-processing computational resources when we use LIDAR technology.
The most notable disadvantage of LIDAR is the high cost of equipment, installation and commissioning. Although in recent years topographic quality LIDAR sensors have appeared with very promising prices. Such is the case of the Livox L1 sensor for unmanned vehicles, which is allowing many advances in the capture of open source geospatial data at very affordable costs.
In the LATAM region, it is still essential to disseminate the use of the LIDAR methodology. While it is true that there are several projects in which ground scanners are used, there is still some uncertainty in the accuracies with unmanned aerial systems. Remember that LIDAR systems, like photogrammetry systems, can have a workflow in real time or in post process (RTK and PPK respectively) and do not require support or control points.
There are several brands of LIDAR sensors that we find in LATAM, such as RIEGL, Faro, Leica and recently DJI presented us with its Livox L1 sensor for the drone that has been revolutionizing the surveying industry, the Matrice 300 RTK and other similar models.
LiDAR technology vs Photogrammetry (precision)
The use of photogrammetry with Drones has been consolidated for many years as a technique of good precision for large areas. The question that we can ask ourselves is how to manage or obtain optimal precision with an airborne LIDAR. Next, we will answer this question.
An aerial LIDAR contains a series of orientation sensors such as accelerometers, magnetometers, among others, as well as a processor that will be managing, processing and calculating the interaction of these sensors in real time.
For the georeferencing of the data obtained, an RTK/PPK quality GNSS is always used, so the precision and accuracy of a LIDAR survey will be around 5 to 8 centimeters.
At METTATEC we integrate different sensors, vehicles, and hardware and software solutions that allow us to capture and make the most of geospatial information. If you require a Geospatial Data Capture and Management service, do not hesitate to contact us, we carry out quality work with the most modern equipment in the geodetic market.