Page 15 - EngineerIt February 2021

AUTOMATION AND CONTROL

Modern LIDAR systems: sensing

for every industry

Tony Pirc, Applications Engineer

ecent advances in technology have unlocked Hasn’t LIDAR been around for decades?
unprecedented modalities of capturing the physical What is new?
Rworld in digital form. One of those modalities is light Radar has been used very successfully for many decades and
detection and ranging, or LIDAR. Many applications and will continue to be invaluable, but now we have an additional
industries have adopted LIDAR technology; these range from tool coming up on the horizon that will allow us to further extend
geographical survey to 3D structural mapping and object our ability to sense things in this world. Until now, LIDAR has
recognition. Industries include manufacturing automation, safety, been restricted to applications that are large and expensive (like
agriculture, and many others. All these applications and specialised surveying equipment) or smaller and simpler (like
industries have leveraged LIDAR to drive down costs, create speed detection devices used by law enforcement).
safer environments, improve efficiencies, or even do things not A high performance LIDAR system must meet certain criteria.
previously possible. To better understand the impact of LIDAR, it The transmitting portion, for example, needs to pulse the laser for
is important to understand what this technology is, what was 3 ns to 5 ns at a peak of 40 A to 80 A to make it attractive for
used before it, and what LIDAR allows us to actually measure automotive applications. Laser drivers are finally approaching these
and, more importantly, do. metrics of interest, making the application of LIDAR a reality. Other
At the most fundamental level, LIDAR is a system that factors include small and efficient power management, integration
bounces light off objects to detect them. This boils down to a of sub-systems, inexpensive high speed data processing, and
transmitting portion of the system that emits light, and a sophisticated software to make sense of all this data. Our ability to
receiving portion that measures the reflected light’s time of push LIDAR systems’ performance up and power budget down is
return. This happens to be exactly how traditional radar systems nearing the point where they make sense to use in many
work, with one very important difference—the wavelength of applications where they simply could not meet demands previously.
LIDAR systems is in the order of ten thousand times shorter
than the shortest radar wavelengths.

Figure 1: What we see vs. what a radar sees.

What is different with LIDAR?
What does a much shorter wavelength enable us to do that we
could not do with radar? A shorter wavelength allows us to see a
much higher resolution image, due to a physical limitation that a
measurement cannot be more precise than what is used to
measure it. Even with tricks in software and signal processing, an
object can be characterised to only a limited extent if you are using
long wavelengths to do it. With LIDAR’s shorter wavelength, we
can scan the environment for objects and their features, instead of Figure 2: Leaps in development of LIDAR and MEMS
being limited to only knowing location, rough size and velocity. technology over 13 years, respectively.

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