Solid-state LiDAR

Solid-state LiDAR Introduction

The so-called solid-state LiDAR, it is generally recognized that the solid-state LiDAR is non-rotating. Usually, it’s divided into three types, based on phased array, Flash, and MEMS.

The phased array principle is adopted to realize the solid-state LiDAR, which completely eliminates the mechanical structure, and changes the exit angle of the laser by adjusting the phase difference of each emitting unit in the emitting array. Optical phased arrays generally use electrical signals to strictly control their phase to achieve beam pointing scanning, so it can also be called electronic scanning technology. However, side lobes are also easy to form, which affects the distance and angular resolution of the beam, and it is difficult to produce.

The solid-state LiDAR using 3D Flash technology is a non-scanning radar that emits area array light and is a LiDAR that focuses on 2D or 3D images. Although the stability and cost are good, the main problem is that the detection distance is relatively short, and there are still problems in the reliability of the technology.

The MEMS-based solid-state LiDAR uses a micro galvanometer to change the emission angle of a single transmitter for scanning, thereby forming a scanning field of view of an area array. At present, many manufacturers are developing laser radar based on MEMS method. Compared with the former two, MEMS is technically easier to implement, and the price is relatively low. Therefore, the most manufacturers are unanimously optimistic.

Solid-state LiDAR has many advantages. First of all, its structure is simple and its size is small. Because it does not require rotating parts, it can greatly compress the structure and size of the radar, increase its service life, and reduce costs. Secondly, due to the fixed optical structure of mechanical LiDAR, it is often necessary to precisely adjust its position and angle to adapt to different vehicles. Solid-state LiDAR can be adjusted through software, which greatly reduces the difficulty of calibration and hastens scan speed and accuracy.

However, solid-state LiDAR also has its corresponding shortcomings. Solid-state means that LiDAR cannot rotate 360 degrees and can only detect the front. Therefore, to achieve omnidirectional scanning, multiple solid-state LiDARs need to be arranged in different directions. In addition, solid-state LiDAR still cannot solve the disadvantages of inability to perform performance in extreme climates. If combined with a millimeter-wave radar that works around the clock, it will inevitably greatly improve the detection performance of autonomous vehicles.