Besides measuring underwater surfaces, Bathymetric lidars typically locate objects in the water. Moreover, these lidars help marine scientists gather hydrographic data such as coastlines, harbors, and banks.
Lidar units can orbit the earth, too, in the form of satellites.
The ultimate goal of satellite lidars is to produce high-resolution, laser-ranging observations of Earth’s 3D structure. Whereas land-based and airborne Lidars provide a high-resolution digital surface model, satellite LiDARs reveal crucial details of the vertical profile of the atmosphere globally.
It offers information about elevation changes and the vertical distribution of clouds and aerosols (small particles in the atmosphere).
NASA is a pioneer in adopting satellite lidars – its Langley Airborne High Spectral Resolution Lidar (HSRL) characterizes clouds and aerosols. HSRL works similarly to Radar. But it uses light waves instead.
The HSRL scientist studies the aerosol size, composition, distribution, and movement from an airborne platform.
What is Lidar Mapping?
LiDAR mapping is an exciting new technology – it combines an integrated Inertial Measurement Unit (IMU) with a GNSS receiver to create real-time maps.
It captures detailed 3D information making it perfect for self-driving cars or other applications where timing and accuracy are crucial factors.
Digital Elevation Models (DEMs)
Often used with lidar – Digital elevation models (DEMs) are 3D representations of the earth’s surface based on elevation data.
Using both technologies together, you can get more accurate measurements because lidar can penetrate through things like trees and water, which would otherwise block the signal from reaching the ground.
Digital Terrain Models (DTMs)
A DTM represents the ground surface as you view it from above — it contains all sorts of information about hills, valleys, ridges, etc. It’s similar to an elevation map since both contain topographical information. However, an elevation map only has two dimensions (x and y). In contrast, a DTM has a third dimension (z) representing depth or height.
It allows you to see how high or low things are relative to one another and how deep they are relative to their surroundings.
Types of LiDAR Technology by Application
Few more types of Lidar based on other classifications:
Differential Absorption LiDAR (DIAL)
DIAL monitors the ozone layer in the lower atmosphere. More precisely, it measures the gas concentration and checks the atmosphere’s pollution level.
It’s tricky to gather wind data since the wind changes its direction abruptly. Here, this lidar measures wind speed and direction in 360 degrees with high accuracy. Furthermore, it begets turbulence information.
ESA’s (European Space Agency) research satellite Aeolus produces wind profiles with Lidar. Orbiting around the earth at an altitude of 320 km, Aeolus shoots short pulses of UV light at the earth. A telescope then gathers the scattered light by aerosols and assesses the light pulse duration and frequency.
Raman lidar goes one step beyond in measuring different levels of water vapors, temperature, and aerosols in the environment. It detects signals with inelastic scattering – a process that detects signals in reflected-back laser pulses with diverse wavelengths.
HSRL, is an acronym for High Spectral Resolution LiDAR and is similar to Raman lidar but with an airborne system. It also measures the environment’s ratio to water vapors and aerosols.
Initially, lidar was passive in making headway since major technologies, such as GPS and IMUs, were missing. When LiDAR gave itself access to these newer technologies, its growth became exponential.
Demand for mapping applications during the 1990s gives rise to the very first commercial LiDARs. Since technological advancement was at its peak, LiDAR, not missing the opportunity, further coupled itself with aerial cameras. It enables photogrammetry and high-resolution terrain mapping, which helps Lidar provide accurate land surveying and mapping results.
Since then, Lidar has been wreaking unimaginable benefits for scientific fields and daily applications.
Various Applications of LiDAR Technology
This pulsed laser technology has enormous applications for mapping, providing detailed information and data on the environment. Whether in the automotive sector, gaming industry, real estate, or construction, LiDAR offers every industry the edge before setting foot on a racetrack.
Some popular applications of LiDAR technology are:
LiDAR isn’t only useful on earth, It plays a major role in space too, enabling NASA to land lunar vehicles safely.
LiDAR’s laser scanning systems help survey the built environment. Including buildings, road networks, and railways.
Laser scanners can create accurate floor plans and measure indoor spaces.
Smaller and low-range LiDAR scanners help navigate self-driving cars.
LiDar’s range and resolution characteristics allow Geo-scientists to uncover ancient ruins that otherwise would not be easy to investigate.
Multiple lidar sensors identify the shape of the mound that grain makes when poured into the silo. LiDAr also optimizes the movement of automated machinery in harvesting crops.
Since molecules and atoms reflect and scatter light in many ways, LiDAR can measure the atmospheric composition, water vapor, and dust particles.
Why is LiDAR Popular Among its Similar Technologies?
LiDAR isn’t the only remote sensing technology transforming how the world gathers information. RADAR and SONAR are part of the race too. But what makes LiDAR so popular? Let’s have a look:
You might be mindful that RADAR (Radio Detection and Ranging) transmits radio waves and measures the time that waves takes to get back — in turn giving you the details about how far away objects are.
LiDAR works the same way, measuring the ToF with Light waves.
SONAR (sonic detection and ranging) uses sound waves to measure wind speed and direction.
LiDAR, however, has a big advantage over both, though. Light has a shorter wavelength than other waveforms, so it can give you clearer and more accurate outputs. For instance, besides distance details, LiDar also offers details of an object’s shape, position, speed, etc.
How is LiDAR Making its Way Towards Consumer Electronics?
Take a look around you, and you may spot lidar in action — The first thing you may see in your daily life are the gadgets in your hands. For example:
Pushing the boundaries of innovation to enrich the user experience, Apple includes a liDAR scanner in their iPhone 12 pro and iPhone 12 pro max. LiDAr’s capability “to see in the dark” empowers you to autofocus 6x faster in low-light scenes and Night mode portraits.
Moving towards the future, Chinese technology giant Baidu has released its Robo-taxi, with more than 8 LiDARs.
Baidu’s self-driving cars enable you to book a car and reach wherever you want without anyone behind the wheel. Moreover, these cars have dramatically lowered production costs.
Other companies like GM, Honda, and Mercedes-Benz have also shown off their vehicles without steering wheels, using LiDAR sensors instead.
Augmented Reality (AR) Apps
Harnessing the LiDAR scanners, AR apps can detect what’s supposed to be in front or behind a virtual object. For example, Physics Sandbox, an AR game, lets you place virtual blocks in a real environment to see how they interact with one another.
Robot vacuums with inbuilt LiDAR allow navigation and identify obstacles. Using the same technology as self-driving cars, SoftBank created a vacuum sweeper, “Whiz,” that avoids people, glass walls, cliffs, and other hazards during cleaning.
LiDar – Key Takeaways
These key takeaways spell out what is LiDAR technology in a nutshell:
- LiDAR systems create detailed, high-resolution images of objects. They are used to make precise measurements over long distances.
- LiDAR lasers scan the environment around them, getting a more accurate picture of how the area is shaped and what objects they’re near.
- LiDAR mapping can be used with other sensors, such as cameras or radar systems — this means you can get even more accurate data than you would otherwise be able to get.
- Today’s most well-known uses of LiDAR technology include sensors for self-driving cars and meteorology.