Introduction to LiDAR

Abstract

LiDAR uses electromagnetic (EM) waves in the optical and infrared wavelengths. It is an active sensor, meaning that it sends out an EM wave and receives the reflected signal back. It is similar to microwave radar, except at a much shorter wavelength. This means that it will have much better angular resolution than radar but will not see through fog or clouds. It is similar to passive electro-optical (EO) sensors in wavelengths, except that it provides its own radiation rather than using existing radiation, and has many more sensing modes due to control over the scene illumination. LiDAR brings its own flashlight and can therefore see at night using near-infrared wavelengths, whereas passive EO sensors have limited capability in the near infrared at night because of insufficient available near-infrared radiation. This means that LiDAR can have increased angular resolution associated with the shorter wavelengths and still operate 24 hours per day.