Which type of lidar system is most likely to require its own light source?

Active lidar systems are characterized by their use of a dedicated light source to illuminate the area being surveyed. This is a fundamental aspect of how they operate. In active lidar, the system emits pulses of laser light, which then reflect off objects in the environment and return to the system. The data collected from these reflections allows for precise measurements and the creation of detailed 3D maps of the surroundings.

In contrast, passive lidar systems rely on ambient light, such as sunlight, to illuminate the environment they are observing. This means they do not emit their own light and are dependent on external light sources for operation. Coherent lidar systems typically use a laser that produces coherent light, but that does not necessarily imply they need a separate light source; they may still operate in a passive manner when utilized under certain conditions. Aerial lidar systems are a category that can be either active or passive, depending on the specific application and technology used.

The requirement of an independent light source is what distinctly classifies active lidar systems.