Kim Chankyu, Jung Yunho, Lee Seongjoo
The Department of Information and Communication Engineering, Sejong University, Gunja-dong, Gwangjin-gu, Seoul 05006, Korea.
School of Electronics and Information Engineering, Korea Aerospace University, Goyang-si 10540, Korea.
Sensors (Basel). 2020 Nov 22;20(22):6676. doi: 10.3390/s20226676.
As the autonomous driving technology develops, research on related sensors is also being actively conducted. One system that is widely used today uses a light source with a wavelength in the 905 nm band for the pulse Light Detection And Ranging (LiDAR) system. This has the disadvantages of being harmful to the human eye and in making digital signal processing difficult at high sampling rates. The Frequency Modulated Continuous Wave (FMCW) LiDAR system has been proposed as an alternative. However, the FMCW LiDAR is formed with a high beat frequency by a method different from that of the FMCW Radar, which causes a hardware burden on the FFT (Fast Fourier Transform) module for interpreting the beat frequency information. In this paper, the FFT module that may occur in the FMCW LiDAR using Digital Down Convert (DDC) technology is extracted at 256 points, which is 25 times smaller than the existing 8192 points, and the beat frequency is 0 to 50 m at 3 cm intervals. As a result of generating and restoring the distance, the performance of 0.03 m Root Mean Square Error (RMSE) compared to the conventional one was confirmed. In this process, the hardware module was directly mounted and verified on the FPGA. In the case of the Simple Threshold-Constant False Alarm Rate (ST-CFAR) provided, the RMSE was measured by generating beat frequencies from 0 to 50 m at 1 cm intervals, and as a result, the result of 0.019 m was confirmed at 0.03 m in the past.
随着自动驾驶技术的发展，相关传感器的研究也在积极开展。如今广泛使用的一种系统在脉冲光探测与测距（LiDAR）系统中使用波长在905纳米波段的光源。这存在对人眼有害以及在高采样率下数字信号处理困难的缺点。调频连续波（FMCW）LiDAR系统已被提出作为一种替代方案。然而，FMCW LiDAR通过与FMCW雷达不同的方法形成高拍频，这给用于解释拍频信息的快速傅里叶变换（FFT）模块带来了硬件负担。在本文中，利用数字下变频（DDC）技术在FMCW LiDAR中可能出现的FFT模块被提取为256点，这比现有的8192点小25倍，并且拍频在0至50米之间，间隔为3厘米。在生成并恢复距离的结果中，与传统方法相比，确认了均方根误差（RMSE）为0.03米的性能。在此过程中，硬件模块直接安装在现场可编程门阵列（FPGA）上并进行了验证。在所提供的简单阈值恒虚警率（ST - CFAR）的情况下，通过以1厘米的间隔生成0至50米的拍频来测量RMSE，结果在过去0.03米的情况下确认了0.019米的结果。
