激光雷达接收机中时刻鉴别模块的研究和设计

Design of Time Discrimination Module in LiDAR Receiver

摘要:

时刻鉴别在激光雷达接收机电路中决定着系统整体的测量精度。考虑到传统的前沿时刻鉴别法测量精度不高,而恒比定时法又存在大量的器件损耗,提出一种新的时刻鉴别法。首先采用高、低两个增益并联的电压放大器,获得两个具有不同增益的脉冲电压信号；再通过四个比较器获得两个脉冲电压信号的前后沿；最后通过几何平均算法获得回波脉冲的形心,从而确定回波到来的时刻。Matlab仿真结果表明,所提时刻鉴别法的鉴别精度优于传统的时刻鉴别法。通过Multisim对时刻鉴别模块进行仿真,结果显示电压放大器和比较器的输出波形均符合预期效果。最后把设计的时刻鉴别模块应用于接收机中进行实验,结果表明该模块可达到三维成像激光雷达接收机电路的系统精度要求,有较好的三维成像效果。

Abstract:

The time-discrimination method determines the measurement accuracy of an entire system in the receiver circuit of a LiDAR(LightLaser Detection and Ranging). As the accuracy of the traditional leading-edge time discrimination method is not high and the constant-ratio timing method presents considerable device loss, a new time discrimination method is proposed. First, two voltage amplifiers with high and low gains are used in parallel to obtain two pulse-voltage signals with different gains. Subsequently, The front and back edges of the two pulse voltage signals are obtained using the four comparators. Finally, the centroid of the echo pulse is obtained using a geometric averaging algorithm, to determine the arrival time of the echo. MATLAB simulations showed that the accuracy of the proposed method is better than those of traditional methods. The output waveform of the voltage amplifier and comparator conformed to the expected results obtained by simulating the time-discrimination module by employing Multisim. Finally, the time application of the discrimination module designed by the proposed time discrimination method to the receiver revealed that the module satisfied the system accuracy requirements of the 3D imaging LiDAR receiver circuit in experiments, demonstrating a good 3D imaging effect.