LiDAR of the air: An overview of LiDAR technology, the different types of LiDAR and key applications

LiDAR – a term that you’ve probably heard thrown around a lot in the “tech” world. LiDAR, an acronym for Light Detection and Ranging is a remote sensing technology that uses light pulses to measure distance. Using light to measure distance is not a foreign concept; it’s been around since the 1960s; however, LiDAR didn’t quite take-off until the 1980s until it was used in explorative space research.

Fast forward to the present day- LiDAR has become the latest buzzword in driving technological innovation. As it becomes more refined, LiDAR isn’t just for NASA… it has slowly translated to more immersive uses across various industries, devices, and applications!

Are there different types of LiDAR systems?

All LiDAR systems work on the same principle - Time of Flight (ToF). A LiDAR sensor emits light pulses into the environment; these pulses bounce off objects and return to the sensor, the time taken for each pulse to return is used to calculate the distance between the sensor and the object or surface. 

At a high level, there are two types of LiDAR systems:

• Airborne
• Terrestrial

With LiDAR technology gaining momentum, it’s the perfect time to learn more about the different types of LiDARs, when it is used and how to use it. Before choosing a LIDAR for your project, it’s always a good idea to know more about the different types of LiDARs so that you can select the right LiDAR for your application!

Airborne LiDAR

A quick rewind to the 1960s, where the first LiDAR systems were invented – to be precise, Airborne LiDAR systems. At that point, this type of LiDAR was predominantly used in aeronautics and aerospace applications. You can read about the evolution of LiDAR technology here.

How does it all work? With airborne LiDAR, the LiDAR sensor and receiver are installed onto a drone, plane, or type of aircraft.

Benefits of airborne LiDAR systems

Airborne LiDAR systems have several advantages over alternative technologies : 

• Airborne LiDARs are the best option for projects that require data collection over a large area. It’s fast - a LiDAR can collect data as quickly as the aerial vehicle can move.
• Airborne LiDARs can be set up to collect topographical or scanning data whilst at the same time another LiDAR sensor can be set up to ensure that the UAV is able to perform other functions such as measuring the UAVs height above ground-level altitude; perform “sense and avoid” functions so that the UAV does not crash into other objects such as trees, power lines, and signs in its flight path; allows the UAV to keep accurate and safe terrain following and on projects running in a GPS denied areas (like underground) - perform SLAM functions.
• Airborne LiDAR are provide better topographical data than other methods of data collection as airborne LiDARs can see through dense vegetation, trees and leaves, recording and tracking multiple data points providing more accurate and useful data.
• Airborne LiDARs gather highly detailed data of very complex or possibly dangerous terrains (when in normal cases, it would be considered unsafe to survey).
• Airborne LiDARs collect accurate and precise data - without compromising on privacy laws around the use of UAVs as LiDAR produces data points - not complete 3D images.

Types of airborne LiDARs

Airborne scanning LiDARs can be further divided into two main categories: 

• Topological LiDARs: Used for monitoring and mapping topography of a region; and 
• Bathymetric LiDARs: Used for measuring the depth of water bodies. 

However it is important to keep in mind that both Topological and Bathymetric scanning UAVs can use sensor LiDARs themselves to operate! This type of LiDAR allows the UAV itself to:-

• Maintain a specific height above ground
• Calculate the UAVs altitude
• Have terrain following capabilities.
• Perform Simultaneous Localisation and Mapping or SLAM in GPS denied environments
• Sense and Avoid other flying or stationary objects

When do you need an airborne LiDAR system?

Before investing in an Airborne LiDAR system, you need to consider the following:

• Consideration for UAV Height above ground/ Terrain following/ Sense and Avoid/ SLAM: Do you need your UAV to collect highly detailed data whilst maintaining a constant height above the ground, accurately tracking the ground below and not crashing into anything? If you said yes to any or all of these - airborne LiDAR is the answer for you!
• Consideration of GPS vs SLAM: Do you need to collect data in a GPS denied area - like underground? Yes? Well the LiDAR is your answer.
• Terrain: The terrain is essential when selecting an effective LiDAR system. Does your project include forests, mountains, or coastal areas? Do you need highly detailed data? Then LiDAR is the solution! One of LiDAR’s unique capabilities is its ability to penetrate through foliage or dense vegetation recording multiple data sets - giving you a full picture of the terrain you are mapping
• Area of project: Does your project need to cover a vast amount of land? If you answered yes, then airborne LiDARs are perfect for your project. Remember: As long as the UAV or aerial vehicle is running, there is no time limit on how much data can be collected. 
• Applications: These LiDARs are best suited for projects where you need measurements of the ground surface, vegetation, roads, underwater and buildings. This is especially true in cases where your project does not require a 3D-generated image or photo. 

LightWare can help you with your airborne challenges!

LightWare can help you find the right sensing LiDAR for your project. We offer a range of sensors that integrate with common autopilot systems such as Ardupilot and PX4. 

Also, we know that every customer has a unique problem case; therefore, we are more than happy to offer customised microLiDAR solutions for your data collection needs!

Do you need help exploring LiDAR sensors to problem solve a specific use case? When using our range of airborne sensors - we can offer accuracy, precision and privacy compliance of your data collection. To find out more visit our website and contact us for more information.