Terminology » LiDAR vs RADAR: A Detailed Comparison

LiDAR vs RADAR: A Detailed Comparison

lidar radar sensing detection technology

Introduction

When it comes to sensing and detection technologies, LiDAR (Light Detection and Ranging) and RADAR (Radio Detection and Ranging) are two of the most commonly discussed options. While both are used to detect objects and measure distances, they operate on vastly different principles and are suited to distinct applications. This guide explores the key differences between LiDAR and RADAR, including their working mechanisms, advantages, and use cases, to help you better understand which technology might be right for your needs.

What is LiDAR?

LiDAR (Light Detection and Ranging) uses laser pulses to measure distances and create detailed 3D maps of environments. It is widely used in applications like autonomous vehicles, mapping, and environmental studies due to its high precision and ability to generate detailed spatial data. It can be used to analyze targets with a wide variety of materials such as dust, rain, non-metallic objects, molecules, chemical compounds, etc.

Following are the features of LiDAR:

LiDAR is one of the optical sensing technologies used to determine the range of distant targets and other parameters. It uses lasers for its operation. Different wavelengths are used by LiDAR depending upon the distant object material.
LiDAR uses Near Infrared (NIR) and Visible Light frequencies to image objects.
Laser beams are used to measure the properties of scattered light and to create points for 3D mapping.
LiDAR uses three platforms viz. ground, airplane, and space for its applications.

LIDAR

The figure depicts a typical block diagram of a LiDAR system. The LiDAR system contains a laser part, photodetector, receiver electronic circuitry, scanner and optics, position and navigation subsystems, etc.

What is RADAR?

RADAR (Radio Detection and Ranging) uses radio waves to detect and measure the distance, speed, and position of objects. It is commonly employed in aviation, weather monitoring, and defense due to its ability to operate effectively in adverse weather and over long distances.

Radar

Following are the features of a RADAR system:

It uses EM waves in the frequency range from 3 MHz to 300 GHz.
The radar transmits waves at about 3 x 10⁸ m/s in the air.
The EM waves transmitted toward the target object are reflected from it. These reflected waves are received by the receiver and are analyzed to determine the size and range of the target object and other parameters.
It is mainly used for military and airport surveillance.

Following are the types of RADAR based on their principle of operation:

Primary radar, Secondary radar
CW radar, Pulse radar
Monostatic Radar, Bistatic Radar
Radar types based on applications of use e.g. Weather radar, search radar, automotive radar, ground-penetrating radar etc.

Difference between LiDAR and RADAR

Let us compare LiDAR vs Radar in tabular format.

Parameters	LiDAR	RADAR
Full form	Light Detection and Ranging	Radio Detection and Ranging
Technology	It uses laser light pulses for sensing.	It uses radio waves for sensing.
Wavelength	Shorter wavelength (Typically in near infrared range)	Longer wavelength (Typically in the microwave or radio frequency range)
Range	Short to medium range (typically up to a few hundred meters)	Longer range (can reach several Kilometers)
Resolution	High spatial resolution (sub-centimeter to centimeter level)	Lower spatial resolution compared to LiDAR
Accuracy	Very accurate in detecting object positions and shapes	Slightly less accurate than LiDAR in terms of spatial precision
Sensitivity to weather	LiDAR can be affected by fog, heavy rain, and snow.	Radar is less sensitive to weather conditions and can operate in rain.
Penetration	Generally cannot penetrate opaque obstacles (e.g. heavy rainforest canopy)	Can penetrate some obstacles like foliage and light rain
Safety	Generally considered safe for the eyes and skin	Considered safe but can be hazardous if used improperly
Cost	Typically more expensive compared to radar systems	Often more cost-effective than Lidar
Application examples	Autonomous vehicles, surveying, 3D mapping, robotics	Aviation (e.g. weather monitoring), automotive (adaptive cruise control), defense

Let us summarize key differences between them.

LiDar uses optical light frequencies whereas Radar uses microwave frequencies.
The type of objects which are located and measured precisely by LiDAR and Radar are different in size and nature.
LiDAR uses charge-coupled devices (CCDs) and lasers for transmission and reception. Radar uses antennas for both transmission and reception.
LiDAR can detect smaller particles with the use of lower wavelengths. Radar has limitations of target size due to the use of a longer operating wavelength.
The performance of LiDAR is degraded due to bad atmospheric conditions whereas Radar can operate even in bad weather conditions.

Conclusion

LiDAR and RADAR each offer unique advantages that cater to different applications. LiDAR is renowned for its high precision and is widely used in mapping, autonomous vehicles, and environmental monitoring. RADAR, with its robust performance in adverse weather conditions, finds extensive use in aviation, defense, and weather tracking. Understanding the differences between these technologies ensures you can select the one that aligns with your specific requirements.