The most important perception organ in the driving scheme of autonomous vehicles is LIDAR (Light Detection and Ranging Radar). The widespread adoption of LIDAR LiDAR has brought autonomous vehicles closer to us ordinary people. What are the optical bands used for LIDAR LiDAR? What are the advantages and disadvantages of different optical bands of LIDAR lidar?
The full name of LIDAR is Light Detection and Ranging Laser Detection and Ranging, also known as Optical Radar. The working principle of LIDAR: Infrared band (currently commonly used are 850nm filter band, 905nm filter band, and 1550nm filter band for emitting, reflecting, and receiving to detect objects).
The 1550nm indium gallium arsenide (InGaAs) currently used in unmanned vehicles is safer compared to 905nm silicon photodetectors, as it can increase the power of the laser without harming eye health.
At present, the infrared laser in the 905nm filter band cannot have too high a power due to legal regulations, because 905nm red light is invisible but can be directly transmitted to the human retina. Therefore, the detection distance of 905nm infrared light cannot meet the detection requirements of autonomous vehicles. So LiDAR radar needs to achieve a detection distance of 200-300 meters, and infrared light in the 1550nm band can meet the requirements (light greater than 1400nm cannot be projected onto the retina). Currently, infrared light in the 1550nm band is also a relatively mature application detection solution abroad.
A well-known enterprise in the field of solid-state LiDAR uses 1550nm LiDAR laser with a power 40 times that of traditional silicon optoelectronic systems. After comparison, it is found that it can not only improve the signal-to-noise ratio and reduce the pulse width, but also has a low pulse repetition frequency and duty cycle. At the same time, it can improve the effective detection range of the laser radar, especially in complex weather conditions where the reflectivity of the detected object decreases, resulting in a shorter effective range of the laser radar. However, increasing the 1550nm laser radar power can further solve this problem. Even for objects with relatively low reflectivity, the effective range of laser radar from well-known companies in the industry can reach 200 meters.
