The technology behind vehicle autonomy and driverless cars relies on a number of technologies. Among these technologies is RADAR and LiDAR. Both of these technologies have their functions in autonomous vehicles but come with their own blend of strengths and weaknesses. We examine both technologies and how each of them has been used in this future automotive technology.
RADAR technology has been around for several years now and has been used to determine the range, velocity and angle of objects. The best thing about RADAR in autonomous vehicles is that it is lighter as far as computation is concerned and can be applied in all conditions. There are three types of RADAR sensors classified according to the range of operation. Short Range radar is radar that can be operated between distances of 0.2m to 30 meters. Medium Range Radar can be operated between 30m-80m while Long Range Radar works between 80m to 200m.
Long range RADAR is the radar that is used almost exclusively in Adaptive Cruise Control (ACC) as well as highway Automatic Emergency Braking System (AEBS). This means that without this important technology, it would be impossible to have self-driving cars sense and apply brakes whenever an object is detected on its course. However, vehicles that use Long Range Radar for ACC and AEBS have certain limitations and challenges that prevent them from detecting certain conditions independently. For instance, this technology may not be able to sense a vehicle that is crossing in front. In addition to that, the sensor may also not give the exact profile or position of a smaller vehicle such as a motor cycle. Some limitations indicate that the sensor sometimes reacts to objects that are outside of the road when the vehicle gets to a bend or a road curvature.
In order to overcome this challenge, the RADAR sensor needs to work collaboratively with camera sensors that are attached to the vehicle. This will ensure that the profiles of the objects being detected by the sensors are complete and provided in the exact context.
LiDAR technology is used to measure the distance between the sensor and the object by calculating the time taken for a laser pulse to travel from the sensor to the object and back to the sensor. When LiDAR sensor is placed on top of the vehicle, it will provide a holistic 360 degrees view in 3D of all the potential objects that the vehicle needs to avoid. This capability has allowed the LiDAR technology to be used in autonomous vehicle since time immemorial.
Since their inception, LiDAR sensors have increasingly reduced in size and cost over time but some of the more commonly used models still cost more than RADAR sensors or camera sensors. Some even cost more than the vehicles they are mounted on. The LiDAR used in automotive systems or autonomous vehicles uses a wavelength of 905nm and a range of about 200 meters even in restricted Field of Views. In addition to that, more and more companies have developed LiDAR that uses up to 1550nm wavelength with a longer range and improved accuracy.
Unlike RADAR technology, LiDAR requires optical filters that are used to remove sensitivity to ambient lighting and prevent other LiDARs from spoofing. The technology used in LiDAR also needs to be eye safe to protect the eyes from damage. Both LiDAR and RADAR technologies have found importance in automotive self-driving vehicles and competition between the two is growing. LiDAR technology is more expensive than RADAR technology but newer sensors are increasingly becoming cost effective and the same can be said of RADAR technology. Experts continue to opine that while both of these technologies are important in autonomous vehicles, value will be achieved if they are used in combination as opposed to when they are used separately. Both of them have their own strengths and weaknesses and it would be important to have them utilized together in order to achieve full capabilities.
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