Why is LiDAR so great?

No other sensor has gained a level of general popularity equal to that of LiDAR. While sonar and radar are commonly known, the advent of recreational and commercial drone use has catapulted LiDAR into the limelight.

The technology of LiDAR has been in use for around six decades but wasn’t widely applied until the 1980’s when it was used by NASA (nowadays it’s very likely to be in your smartphone!).

LiDAR uses the time of flight, or ToF, principle to measure distance. The time it takes for a pulse of light to leave and return to a sensor is converted to a distance measurement (given specific calibrations per use).

When Would You Use LiDAR?

Airborne systems lend themselves nicely to the use of LiDAR sensors. The sensors are relatively lightweight and can be used to navigate a UAV and perform its prime function (topography, oceanic mapping, SLAM, etc).

Because light waves have such short wavelengths, they can detect at higher resolution. This is why LiDAR is being used in 3D mapping and robot systems. They’re also used to count products or levels of fluids.

LightWare is one of our LiDAR brands that has a rich history and a helpful article on other use cases for LiDAR.

What is radar?

Radar uses the same principles as LiDAR, but with radio frequency waves instead of light pulses. The radio waves are emitted, “bounce” off of an object in range, and return to the transmitter.

The main functional difference between light and radio waves is that the wavelength of radio waves is longer than that of light waves. This makes radar a great choice for measuring or monitoring over great distances and for non-distinct, 2D measurements (think of opening an automatic door).

Would you use radar instead of another sensor?

That said, if you need a system to be aware of and respond to specific surroundings in high resolution, you may want to go with LiDAR. If you’re operating outdoors, where rain and clouds or other obstacles can obscure LiDAR, radar would be a better option.

Even with LiDAR around, radar is used in a wide variety of applications and industries. Examples include:

• Parking lot management
• Autonomous driving
• Gas analysis in industrial and medical fields
• Positioning of prosthetics or exoskeletons in sports

How sonar works

Most people are familiar with sonar, thanks to nature documentaries about bats or dolphins. The echolocation of the animal kingdom is the same as that of sonar sensors.

Sound waves are faster in water than light and radio waves, so its applications are primarily in marine or oceanic use. For example, scientists for the National Oceanic and Atmospheric Administration (NOAA) use sonar to make nautical charts.

The two types of sonar

There are two types of sonar sensors: active and passive. Passive sonar sensors only receive sonar waves while active sonar sensors can send and receive sonar waves. To perform any sort of rangefinding with passive sonar you must use multiple sensors to triangulate a location.

Sonar sensor applications are compact and energy efficient–perhaps reasons why Tesla uses ultrasonic sensors in its “AutoPilot” self-driving automobile technology.

How do thermal sensors work?

Thermal sensors are used in thermal imaging, which has applications for security and defense, medical, and industria environments. Like sonar and radar, thermal imaging does not produce a high-relief image–which makes it ideal for applications involved in maintaining confidentiality or privacy (such as falls in assisted living facilities).

What are thermal sensors used for?

Besides using temperature variation to produce an image or detect motion, the measurement of temperature is vital

to certain fields. Thermal sensors can detect leaks in gas lines or simply measure the temperature of someone’s forehead.

Since the COVID-19 pandemic has increased the need for accurate and quick temperature measurements, many thermal imaging technologies have adapted to be more specific and energy/space-efficient.

One benefit of thermal sensors is that they can be extremely compact. Terabee’s Teraranger Evo Thermal 90, for example, weighs only 10 grams.