【摘要】 在调频连续波激光雷达中,用于中频信号采集的模拟-数字采集模块是其关键组件,信噪比、信纳比、无杂散动态范围等参数是衡量该数据采集信号链交流特性的重要指标,直接决定着调频连续波激光雷达的探测范围和测距精度等性能。设计了用于调频连续波激光雷达的中频信号采集模块,获得49.13 dB的信噪比和48.90 dB的信纳比;然后研究了其噪声特性,获得系统的主要噪声来源为采样时钟的相位噪声,并且通过引入数字滤波器将信噪比和信纳比分别提升11.38 dB和11.32 dB,理论上激光雷达的探测范围提高3.7倍。可通过采用专业时钟芯片降低噪声,经计算可将信噪比提高8.65 dB;最后,搭建了光学相控阵调频连续波激光雷达系统,验证了数据采样模块的有效性,完成了40 m距离的探测,最大测量误差为7.7 cm,最大探测范围为133.67 m。更多还原

【Abstract】 The analog/digital acquisition module for intermediate frequency(IF) signal acquisition is the fundamental component of frequency-modulated continuous-wave(FMCW) lidar. Parameters such as the signal-to-noise ratio(SNR), signal-to-noise and distortion ratio(SINAD), and spurious-free dynamic range are major indicators of the alternating current characteristics of the data acquisition signal chain and directly determine the key indicators of FMCW lidar, including the detection range and ranging accuracy.First, this study designed an IF signal acquisition module for FMCW lidar, where the obtained SNR and SINAD were 49. 13 dB and 48. 90 dB, respectively. Second, the study investigated the noise characteristics of FMCW lidar, identified the system noise source as the phase noise of the sampling clock, and improved the SNR and SINAD by 11. 38 dB and 11. 32 dB, respectively, by introducing digital filters, which theoretically increased the detection range of FMCW lidar by 3. 7 times. System noise can be reduced by using cosmetic clock chips, and the SNR can be improved by 8. 65 dB. Finally, an optical phased-array FMCW lidar system was built to verify the effectiveness of the data sampling module and to conduct 40-m range distance detection under a maximum measurement error of 7. 7 cm. The study determined that the FMCW lidar’s maximum detection range was 133. 67 m.更多还原