Lidar was originally defined as lidar, which means "light detection and ranging" in English.

In fact, a more accurate definition is ladar: laser detection and ranging. This is a definition proposed in 2004, which is more in line with the concept of lidar.

Lidar is actually a kind of radar working in the optical band (special band), its advantages are very obvious:

① It has very high resolution: Lidar works in the optical band, and its frequency is 2-3 orders of magnitude higher than microwave. Therefore, compared with microwave radar, lidar has very high range resolution, angular resolution and velocity resolution;

② Strong anti-jamming ability: the length of laser wave, the ability to emit laser beam with very small divergence angle (μ rad level), the small multi-path effect (no directional emission, and the multi-path effect with microwave or millimeter wave), the ability to detect low altitude / ultra-low altitude targets;

③ The amount of information obtained is rich: the distance, angle, reflection intensity, speed and other information of the target can be obtained directly to generate multi-dimensional image of the target;

④ Can work all day: laser active detection, independent of external light conditions or radiation characteristics of the target itself. It only needs to launch its own laser beam, and obtain the target information by detecting the echo signal of the laser beam.

⑤ But the biggest disadvantage of lidar is that it is easy to be affected by the atmospheric conditions and the dust in the working environment. It is very difficult to realize the all-weather working environment.