LiDAR vs RADAR
LiDAR stands for Light Detection and Ranging and RADAR stands for RAdio Detection And Ranging. The functions of LiDAR are similar to RADAR which is to track the position and movements of objects. The differences between them are mainly on working of each and unique applications they are used for. In both LiDAR and RADAR, energy is transmitted from transmitter towards object and reflected energy from object is received by receiver to determine various aspects of the object such as distance, size, speed, movement etc.
LiDAR (Light Detection and Ranging) and Radar (Radio Detection and Ranging) are two different remote sensing technologies used for detecting and measuring objects and their characteristics, typically at a distance. They work based on different principles and use different types of electromagnetic waves.
LiDAR
Following are the features of LiDAR.
• LiDAR is one of the optical sensing technology used to determine range of distant target and other parameters.
It uses laser for its operation. Different wavelengths are used by LiDAR depending upon distant object material.
• LiDAR uses Near Infrared (NIR) and Visible Light frequencies to image objects.
• Laser beams are used to measure properties of scattered light and to create points for 3D mapping.
• LiDAR used three platforms viz. ground, airplane and space for its applications.
• The common applications include meteorology, space exploration, transportation, vehicle anti-collision,
robotics, agriculture etc. It can be used to analyze targets with wide variety of materials such as dust, rain, non-metallic objects,
molecules, chemical compounds etc.
The figure depicts typical block diagram of LiDAR system. LiDAR system contains laser part, photodetector, receiver electronic circuitry, scanner and optics, position and navigation subsystems etc.
RADAR
Following are the features of RADAR system.
• It uses EM waves in 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 towards target object are reflected from it.
These reflected waves are received by receiver and are analyzed to determine size and range of 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 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. Adverse weather conditions can reduce its effectiveness. | Radar is less sensitive to weather conditions and can operate in rain and light to moderate fog. It can penetrate some types of precipitation. |
Penetration | Generally can not 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 where as 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 transmission and reception both.
➨LiDAR can detect smaller particles with the use of lower wavelengths. Radar has limitations of target size due to use of longer operating wavelength.
➨The performance of LiDAR is degraded due to bad atmospheric conditions where as Radar can operate even in bad weather
conditions.
Conclusion : In summary, LiDAR and Radar are remote sensing technologies that use different parts of the electromagnetic spectrum and operate on different principles. LiDAR provides high-resolution, precise 3D information for relatively short to medium distances, while Radar offers longer-range detection but with less detailed spatial information. The choice between the two technologies depends on the specific requirements of the application and environmental conditions.
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