Entering August, it can be found that the models equipped with LiDAR have been listed on the market recently, including Jihu Alpha S HI version, Nezha S, Avita 11, Zhiji L7, ideal L9, Weilai ES7 and so on. From the technical route, the lidars used in the recently launched models are mainly in the form of hybrid solid-state, including the Sagitar Juchuang M1 using MEMS micro-galvanometer technology, Huawei’s 96-line lidar using rotating mirror scanning, and Tudatong The Falcon adopts a two-dimensional scanning form composed of one light source and two optical devices.
In order to reduce moving parts and improve reliability, pure solid-state is the clear development direction of LiDAR. The technical route of pure solid-state lidar includes Flash and OPA according to the scanning mode. According to the ranging principle, it is divided into two types: ToF and FMCW (frequency modulated continuous wave). Currently, the lidars that have been launched on the market all use the ToF ranging principle. .
Recently, Aeva announced that the first batch of Aeries II 4D lidar sensors have been successfully put into production and delivered to strategic customers, which is an important milestone for the company towards mass production. At the same time, this seems to be the first LiDAR product to be put into production in the current FMCW track.
According to Aeva, in addition to providing accurate 3D position sensing, Aeries II can also directly measure the velocity of each point with cm/s accuracy, while providing a resolution including 4 million original points per second and a maximum field of view of 120° ×30°, and a maximum detection range of up to 500 meters. In terms of field of view and detection distance, it surpasses other lidars that have been mass-produced.
At present, the common ToF ranging lidar measures the distance from the irradiated object by directly measuring the time difference between the emitted laser and the echo signal. The main advantages are fast response speed and high precision, but the anti-interference ability is weaker than the FMCW method. , and to obtain sufficient detection distance, a larger power transmitter laser is required.
In FMCW, the laser is used as a signal wave, similar to radar, the echo signal is coherent with the reference light, and the frequency difference is obtained by using the frequency mixing detection technology, and the time of flight of the light is obtained indirectly, which is calculated from the distance of the measured object. The advantages include that when detecting moving objects, the speed of the object can also be measured by the Doppler effect, and due to the use of the concept of channel multiplexing, the anti-interference ability is extremely strong.
In addition, the structure of FMCW lidar is simpler and more reliable than ToF. Aeva said that Aeries II uses unique FMCW lidar chip technology, without any fiber components, and integrates all key sensing components (including transmitter, optical components and receivers) integrated on a silicon photonic chip in a compact module. This makes FMCW lidar easier to achieve mass production and smaller in size.
Of course, due to the high price of the ultra-high-precision components required by the current FMCW lidar, the system is technically difficult, and the cost is high before mass production is realized. Previously, Mobileye announced that it will independently develop the silicon photonic chip + FMCW technology route, but it plans to mass-produce it by 2025. Another company, Blackmore, which is more advanced in FMCW LiDAR, is said to be priced at 100,000 LiDAR products for testing. US dollar one. In addition to Avea, Mobileye, and Blackmore, other lidar companies taking the FMCW route include Strobe, Guangshao Technology, Guangbo, Luowei Technology and so on.
Last year, Luowei Technology launched a mature self-developed silicon photonics OPA+FMCW chip technology solution, but has not disclosed the time node of mass production. Industry insiders believe that in the long run, the 1550nm+OPA+FMCW solution is the most ideal solution for future lidars.
In theory, the ranging principle of FMCW can actually be matched with scanning methods such as mechanical scanning, MEMS galvanometer, and OPA. At present, OPA technology is still a long way from mass production. In the short term, MEMS+FMCW lidar will be the first to land. form.
But at present, at least until 2025, the lidar we can see on the market will be in the form of ToF ranging. Pure solid-state lidars, such as lidars using Flash light sources, are expected to appear on mass-produced models in 2023. But in the end, which form of lidar will become the ultimate winner depends on who can mass-produce it and is cheap enough, otherwise technological advancement will not be able to turn into an advantage.