Light Detection and Ranging is no longer a scientific technique exclusively for specialists. In fact, LiDAR technology has become an essential tool for many industries. It’s transforming urban planning processes and has become a leading technology through innovative projects such as self-driving cars.
With LiDAR technology on the rise, now is the perfect time to learn more about what LiDAR is, how it works, and how to use it. So here’s everything you need to know about it.
What Is LiDAR?
First thing’s first, what exactly is LiDAR? To put it simply, LiDAR is a remote sensing technology and surveying method. It uses laser scanners to measure distances and dimensions of landscapes and buildings.
LiDAR sends pulses of light to objects such as buildings, roads, and sidewalks, The sensor then measures the time it takes for the light waves to bounce off the obstacle or surface and return to the system. The LiDAR system then calculates measurements using the velocity of the light pulses.
LiDAR first appeared in the 1960s when the laser scanners were mounted to planes. However, it only really became popular after the introduction of GPS in the 1980s. With GPS, the data collected from LiDAR scans was used for accurate geospatial measurements. These measurements can now be used to create digital 3D models representing the scanned landscape.
How Does LiDAR Work?
Just like radar uses radio waves and Sonar uses sound waves, LiDAR uses light waves from a laser to detect objects. The LiDAR system takes into account the total time that the light takes to hit the target object and reflect back to the scanner. Once this happens, the system calculates the total distance with the help of the velocity of light. This process is also called the “Time of Flight” measurement.
Today’s LiDAR systems are powerful enough to comfortably fire up to 500,000 pulses every second.
All of the pulses collected during a LiDAR scan are put into a point cloud (a database of coordinates). The point cloud can then be used to create 3D meshes and models, with the help of an effective point cloud processing software.
These 3D meshes play a vital role in 3D modeling for different fields, such as architecture, construction, medical imaging, manufacturing, 3D printing, and other virtual reality applications.
Different Components of the LiDAR System
LiDAR systems are made up of several different components that all work together to collect point cloud data. Most people know that LiDAR systems use lasers, but it’s also worth knowing about the other key parts that make data generation, recording and geo-referencing a hassle-free process.
Here are some of the key components of LiDAR systems:
The laser’s light bounces from the LiDAR system to surfaces and objects and then reflect back to the sensor, which then measures the velocity of these light pulses.
Different types of LiDAR can use different lights. For example, bathymetric LiDAR systems use both infrared light pulses and green lasers.
The scanner determines how far laser light can reach, and the speed at which landscapes are scanned. They also use mirrors to increase the range of the laser’s light.
GPS (Global Positioning System) & IMU (Inertial Measurement Unit)
GPS is what made LiDAR the unbeatable tool it is today. Position and navigation systems allow airborne LiDAR to determine the exact location of the system so that measurements are calculated correctly.
The sensor in a LiDAR system is what measures light velocity and distance. Light is transmitted from the sensor to objects or surfaces and then bounced back to the sensor. So this component is almost like the brain of the LiDAR system.
Each of these components plays a critical role in the LiDAR process and makes it incredibly easy for researchers to obtain needed data in the most accurate way possible. So, learn about all these components along with an appropriate LiDAR definition for maximum benefits.
Types of LiDAR Systems
There are a few different types of LiDAR, but they all fall under the two primary types: Airborne and Terrestrial. While all types of LiDAR have similar functions, there are a few differences between them:
This type of LiDAR system is installed on top of a drone or helicopter. It emits lights toward the ground, which returns to the sensor. It’s further divided into two types — Bathymetric and Topographic LiDAR.
Bathymetric LiDAR: This type of LiDAR is mainly used for measuring the depth and elevation of water bodies. As part of the bathymetric LiDAR process, the infrared light goes back to the aircraft, helicopter or drone from the water surface while the additional green laser light goes through the water and measures its exact depth.
Bathymetric LiDAR is quite useful near coastlines, shores, river boundaries and in harbors. It’s also used from time to time to locate objects on the ocean floor.
Topographic LiDAR: This type of LiDAR is used for obtaining the surface models that play a vital role in many applications, such as urban planning, forestry, landscape ecology, geomorphology, survey assessment, and coastal engineering.
Terrestrial LiDAR systems are installed on a moving vehicle or tripod for collecting highly accurate data points. Terrestrial LiDAR has two types and plays a vital role in creating 3D modeling and surveying projects.
Mobile LiDAR: Mobile LiDAR systems comprise of the camera, sensors, INS (Inertial Navigation System), and GPS. It is used for observing roads and analyzing infrastructure. They can be mounted on trains, vehicles or even ships, although they won’t be able to scan through water like bathymetric LiDAR.
Static LiDAR: Static LiDAR systems are used for collecting LiDAR point clouds from a fixed location. The LiDAR system is installed on a tripod, and from here, the sensor gathers point clouds. This type of LiDAR can be used to collect data from the exterior as well as the interior of buildings.
Some of the most common applications of the static LiDAR system are in mining, engineering, surveying, and archaeology.
Applications of LiDAR Technology
LiDAR technology makes it incredibly easy to collect crucial data points in remote areas and use them for various short-term and long-term developmental objectives. Here are some of the most common uses of LiDAR.
LiDAR technology can measure the depth of the ocean as well as calculate biomass and phytoplankton fluorescence in the ocean surface. Usually, the process is tough and time-consuming, but LiDAR makes everything easy and hassle-free.
Agriculture & Archaeology
Along with analyzing the yield rates on agriculture fields, LiDAR technology can be used in fertilizer and seed dispersions and crop scouting.
LiDAR allows researchers to create a topological map of the fields. Sun exposure and slopes can be highlighted, making it easier to determine where to apply fertilizer for maximum production.
LiDAR is also used in archaeology, mapping features under forest canopies and helping in field campaign planning. LiDAR quickly produces high-resolution datasets and provides 100% accurate information for field analysis.
Digital Elevation Model (Also known as Digital Terrain Model or DTM)
LiDAR technology has x, y, and z coordinates, and can quickly produce 3D representations of terrain elevations on the earth’s surface. It is used to capture the width, length, and height of the surface when constructing bridges, buildings, and roads.
The high quality and data-rich digital elevation maps generated by airborne LiDAR help researchers to unearth various geomorphic secrets.
With the help of these maps, researchers can detect faults — any discontinuity in a rock’s volume — and measure uplifts.
Military personnel from various countries use LiDAR to survey borders, spot suspicious activities, and objects, and create high-resolution maps of remote locations — making LiDAR vital for national security.
The green light laser used in the LiDAR technology plays an important role in collecting underwater information relating to a river’s flow strength, width, and depth. This information is in turn used to create 3D river models and flood fringe maps.
LiDAR can also be used in the fields of autonomous vehicles, biology & conservation, atmosphere, mining, astronomy, robotics, spaceflight, transport, and wind farm optimization.