基于FPGA的高性能激光雷达测距系统设计

Design of high performance lidar ranging system based on FPGA

针对低功耗激光测距雷达量程和精度难以兼顾的问题,设计了一套基于FPGA的高性能激光雷达测距系统。该系统首先利用14阶M序列伪随机码以100MHz频率调制发射激光,并使用双口BRAM乒乓读写实现回波光子累计,还原回波信号。其次通过相关性计算获取测距信息来建立回波概率模型,并利用质心算法提高测距精度。最后搭建了雷达系统原理样机,在空间环境百米测距时,距离误差稳定在±2cm;利用光纤延时法在14.8km等效目标测距时,测距精度优于0.1m。实验结果表明该系统能够在较低激光调制频率时提高测距精度,有效降低了数据处理难度,最终实现远距离高精度的激光雷达测距。

Aiming at the problem that the range and accuracy of low-power laser ranging radar are difficult to balance,a high-performance laser radar ranging system based on FPGA is designed.The system first uses the 14-order Msequence pseudo-random code to modulate the emission laser at a frequency of 100MHz,and uses dual-port BRAM ping-pong read and write to realize the accumulation of echo photons and restore the echo signal.Then the distance measurement information is obtained through correlation calculation to establish the echo probability model,and the centroid algorithm is used to improve the accuracy of the distance measurement.Finally,aprototype of the radar system is built.The range error is stable at±2cm when the distance is measured in a 100-meter space environment;when the optical fiber delay method is used to measure the equivalent target of 14.8km,the range accuracy is better than 0.1 m.The experimental results show that the system can improve the ranging accuracy when the laser modulation frequency is lower,effectively reduce the difficulty of data processing,and finally realize long-distance highprecision lidar ranging.