【Fig.1-Fig.2】The laser light emitted by 128 channels hits the object and is reflected back, and then returns to the optical path through the rotating mirror, enters the receiving optical path through the beamsplitter, and then reaches the receiving module after a reflection. That's how the whole optical path is structured.
Figure 3] Since a 905nm laser is used, which can be sensed by silicon, the Hesai AT128 uses the same type of SIPM silicon-based photomultiplier tube as the Sutar M1 to receive the return light, which is more sensitive in low light than the APD avalanche photodiode solution. On the receiving module, the 16 detection board modules, which correspond to the positions of the 16 transmitter modules, are staggered in the horizontal direction. The reason for the staggering here is precisely to compensate for the horizontal angle difference between the launch modules.
Figure 4-Figure 5] Enlarge the receiving chip, then magnify, and remove the filter on it, which is a dense array of SIPM.
Fig. 6-Fig. 7] The scanning module consists of a rotating mirror consisting of a three-sided glass and a small motor [Fig. 8 is a motor drive circuit]. 128 parallel lasers, through 16 holes corresponding to the module, and then corrected by reflection and collimation mirrors, are finally projected onto the triangular one-dimensional rotating mirror. Injection, channel 1 is the highest, and the angle between channel 1 and the horizontal plane is positive 129 degrees, channel 128 is the lowest, and the angle is minus 125 degrees, forming a 25 in the vertical direction4 degrees of coverage. This rotating mirror is driven by a motor to rotate continuously to complete the scanning of the laser beam in the horizontal direction. Thus achieving a horizontal 120 degrees and a vertical 25A field of view of 4 degrees – that is, FOV.
Figure 9] If you calculate the number of laser points emitted by the radar per second, that is, the point frequency, Tudatong is about 80-1 million, Sutar is 750,000, and Hesai is 15380 thousand.
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