基于FPGA的远距离单光子精细化时间数字转换电路  

Long distance single photon precision time digital conversion circuit based on FPGA

作　　者：谢达 王春阳 袁凯 卫旭阳 刘雪莲 Xie Da;Wang Chunyang;Yuan Kai;Wei Xuyang;Liu Xuelian(School of Electronic and Information Engineering,Changchun University of Science and Technology,Changchun 130022,China;Xi'an Key Laboratory of Active Photoelectric Imaging Detection Technology,Xi'an Technological University,Xi'an 710021,China)

机构地区：[1]长春理工大学电子信息工程学院,吉林长春130022 [2]西安工业大学西安市主动光电成像探测技术重点实验室,陕西西安710021

出　　处：《红外与激光工程》2023年第10期247-257,共11页Infrared and Laser Engineering

基　　金：国家重点研发计划项目(2022YFC3803702)。

摘　　要：针对星载GM-APD单光子测距系统难以兼顾宽量程高精度测量问题,文中设计了一种基于等效脉冲粗精两级的精细化时间数字转换电路(Time-to-Digital Converter,TDC)。该TDC首先基于分段式计数原理,设计了粗精两级的计数架构,保证了TDC宽量程测量;其次,针对精计数单元,采用时钟等相差相移π/N,生成等效高频脉冲时钟,将精计数单元的计时精度提升N倍;再次采用多计数器双沿间隔计数方法,将精计数单元计时精度进一步提升至2N倍;最后通过模拟仿真与实验验证对文中设计的TDC进行远距离单光子测距性能测试。仿真与实验结果表明:文中面向远距离单光子测距设计的精细化时间数字转换电路在参考时钟为50 MHz时,计时分辨率为416.67 ps,计时量程达1.31 ms。对室内10 m处目标进行100次测距重复实验,测距误差为5.62 cm,对室外参考距离为2616.5 m处目标进行测距实验,测距的方差为0.0017 m,由此可见,基于文中等效脉冲粗精两级精细化时间数字转换电路的单光子测距系统可以实现远距离目标的高精度、宽量程测量。Objective Single photon ranging system is a system that uses the photon level detection sensitivity of GM-APD detector and obtains the distance information of far-field target based on the principle of photon time-of-flight ranging.The system has the advantages of long range and high ranging accuracy,and has great application potential in laser imaging,target detection and other fields.As the core module of single photon ranging system,the range and accuracy of time digital conversion circuit directly determine the working range and ranging accuracy of the ranging system.And in the field of spaceborne detection,the ranging system is required to have the ranging range of more than 100 km and centimeter-level ranging accuracy.At this time,the traditional time digital conversion circuit,limited by the counter number,in order to ensure the ranging accuracy,often lead to the limited system's measuring range,and if the system's range is increased,the system's ranging accuracy is difficult to meet the needs.In this paper,a time digital conversion circuit satisfying both wide range and high precision is designed to realize the wide range and high precision measurement of photon flight time interval.It provides technical support for single photon ranging in the field of spaceborne laser detection.Methods In order to solve the contradiction between wide range and high precision,a refined time digital conversion circuit design method for long-distance single photon ranging is proposed.Firstly,based on the piecewise counting principle,a coarse and fine two-stage counting architecture is designed to ensure the wide range measurement of TDC(Fig.5,Fig.10).Secondly,for the fine counting unit,the clock equal phase shiftπ/N is used to generate an equivalent high-frequency pulse clock(Fig.6),which improves the timing accuracy of the fine counting unit by N times.The timing accuracy of the fine counting unit was further improved to 2N times by using the multi-counter double-edge interval counting method(Fig.7).Results and Discussio

关 键 词：单光子 激光测距 时间数字转换 等效脉冲 GM-APD 

分 类 号：TN743[电子电信—电路与系统]