History of LiDAR

LiDAR has a rich history of over 50 years. It started most of its development in the early 1960s, shortly after the invention of the laser. There had been some earlier LiDAR development prior to the invention of the laser, but the laser has been a critical enabler for LiDAR development. Wind sensing and laser designation were developed starting in the 1960s. I call laser designation a form of bistatic LiDAR because we have an illuminator, which is called the designator, and receiver, which is on the seeker. The illuminator and receiver are separated, so it is a bistatic system. Admittedly, the term LiDAR stands for light detection and ranging, and in a designator there is no ranging, but a designator does use a laser for illumination and a receiver for detection, so we will include it in the discussion of history. LiDAR has become relatively inexpensive and reliable, and has very rich phenomenology, making it competitive compared to alternative sensor technologies, such as passive EO sensing or microwave radar. LiDAR started operating in the visible region (ruby laser), then appeared in the near infrared (Nd:YAG lasers), and next in the thermal infrared (CO2 laser). Many LiDARs are now being developed in the eye-safe, short-wave infrared (SWIR) region (~1.5 μm and beyond).