Lidar system images bullet in flight
Lidar imaging has been around for almost as long as the technology it’s based on, the laser. But unlike its more famous cousin, radar, it was mostly used for research purposes. The reason scientists know so much about the density of aerosols in the upper atmosphere is largely due to the practice of shooting powerful lasers into the atmosphere and examining the return signal.
That sums up the key difference between lidar and radar: lidar operates with a shorter wavelength so it can, in principle, detect and (sometimes) image smaller objects, like aerosol particles.