Research on Night Vision System Based on Range-Gated Imaging

A design of low-light-level night vision system is described,which can image objects selectively in the specific space. The system can selectively image some objects in specific distances,meanwhile ignore those shelters on the way of observation by combining an intensifying charge coupled device(ICCD) with a near infrared laser assisted in vision,whose operation wavelength matches with the photocathode of the image tube,and adopting the gated mode and adjustable time-delay. A semiconductor laser diode of 100 W in peak power is chosen for illumination. The laser and the image tube operate in 150 ns pulse width and 2 kHz repeat frequency. Some images of different objects at the different distances within 100 m can be obtained clearly,and even behind a grove by using a sampling circuit and a delay control device at 100 W in peak power of semiconductor laser diode,150 ns in pulse width of laser and image tube,2 kHz in repeat frequency.

Influence of Range Gate Width on Detection Probability and Ranging Accuracy of Single Photon Laser Altimetry Satellite

The influence of the single photon laser altimeter range-gate width on the detection probability and ranging accuracy is discussed and analyzed,according to the LiDAR equation,single photon detection equation and the Monte Carlo method to simulate the experiment.The simulated results show that the probability of detection is not affected by the range gate,while the probability of false alarm is relative to the gate width.When the gate width is 100 ns,the ranging accuracy can accord with the requirements of satellite laser altimeter.But when the range gate width exceeds 400 ns,ranging accuracy will decline sharply.The noise ratio will be more as long as the range gate to get larger,so the refined filtering algorithm during the data processing is important to extract the useful photons effectively.In order to ensure repeated observation of the same point for 25 times,we deduce the quantitative relation between the footprint size,footprint,and frequency repetition according to the parameters of ICESat-2.The related conclusions can provide some references for the design and the development of the domestic single photon laser altimetry satellite.

A Study on Ranged-Gated Lidar System with Linear Plus

According to the study of super-resolution range-gated system, we proposed an improved system with linear plus detects. And a range function is derived by considering the shot effect noise and dark current noise. The simulation shows that the improved system has a good range accuracy capability.

Parameters Design of Pull-off Deceptive Jamming to Terminal Guidance Radar

A deceptive pull-off jamming method to terminal guidance radar is put forward in this paper.The design rules about the important jamming parameters are discussed in detail,including the number of the decoy targets in range dimension,the velocity of the range gate pull-off,and the number of the decoy targets in velocity dimension and the velocity of the Doppler frequency pull-off.Also,the steps to design these parameters are brought out.The rules and design procedure discussed in this paper have important meaning for the choice of the reasonable jamming parameters in the practical applications,which can help to obtain good jamming effect.

基于BCH码对ADC板卡动态参数测试的设计研究

由于数据在采集过程中处于温度极端、振动或冲击等恶劣环境下极易影响ADC的精度和稳定性,引起误码的情况。因此,通过可靠的纠错编码技术来保证数据采集传输的可靠性和完整性。该文提出一种基于BCH码对ADC板卡动态参数测试的设计。采用子母板设计,Xilinx的Artix-7系列FPGA进行主控。在节约成本的基础上,通过BCH编码减少误码的情况,提高数据采集的准确程度。仿真与实验结果表明,该设计能够对各种ADC进行参数测试,并且编码前后对比,通过BCH编解码可以有效地降低误码情况,对解决高精度数据采集装备问题具有重要的现实意义。

Key technologies implementation of high-repetition-rate satellite laser ranging

Satellite laser ranging （SLR） is one of the major space geodetic instruments, which has various applications in earth science. In this paper, we introduce several issues regarding the key technology implementation of high-repetition-rate SLR system. Compared with traditional technology, using kHz and 8ps pulse width laser component, the data quantity and quality of high-repetition-rate satellite laser ranging （SLR） can be significantly improved. The characteristics of high-repetition-rate laser ranging and the key technologies are presented, including the event timer with the precision of picosecond, the generation of range gate signal, and so on. All of them are based on the Field Programmable Gate Arrays （FPGA） and tested on China mobile SLR system-TROS1000. Finally, the observations of satellite Beacon-C are given.

Electronic mobility in the high-carrier-density limit of ion gel gated IDTBT thin film transistors

Indacenodithiophene-co-benzothiadiazole（IDTBT） has emerged as one of the most exciting semiconducting polymers in recent years because of its high electronic mobility and charge transport along the polymer backbone. By using the recently developed ion gel gating technique we studied the charge transport of IDTBT at carrier densities up to 10^21cm^-3.While the conductivity in IDTBT was found to be enhanced by nearly six orders of magnitude by ionic gating, the charge transport in IDTBT was found to remain 3D Mott variable range hopping even down to the lowest temperature of our measurements, 12 K. The maximum mobility was found to be around 0.2 cm^2·V^-1·s^-1, lower than that of Cytop gated field effect transistors reported previously. We attribute the lower mobility to the additional disorder induced by the ionic gating.

High Accuracy and Real-Time Gated Viewing Laser Radar

A gated viewing laser radar has an excellent performance in underwater low light level imaging, and it also provides a viable solution to inhibit backscattering. In this paper, a gated viewing imaging system according to the demand for real-time imaging is presented, and then the simulation is used to analyze the performance of the real-time gated viewing system. The range accuracy performance is limited by the slice number, the width of gate, the delay time step, the initial delay time, as well as the system noise and atmospheric turbulence. The simulation results indicate that the highest range accuracy can be achieved when the system works with the optimal parameters. Finally, how to choose the optimal parameters has been researched.

激光距离选通三维成像技术研究进展(特邀)

随着人工智能时代的到来,同时获得反映目标辐射特性和纹理特征的高分辨率强度图像以及反映目标和所处场景的三维空间信息的稠密点云数据/三维图像的激光相机雷达技术已成为激光雷达的发展趋势。传统的摄像机与激光雷达复合的技术方案存在异源数据融合问题,尤其是在雾雨雪天气条件下以及水下等传输链路中存在严重散射的情况时难以有效工作。激光距离选通三维成像技术利用单一门控成像器件可同时获得高质量二维强度图像和高分辨率三维图像,其二维图像中的像素和三维图像中的体素一一对应,并继承了激光距离选通成像透散射成像的技术优势,具有实现高性能激光相机雷达的技术潜力。论文系统综述了步进延时扫描、增益调制、距离能量相关等激光距离选通三维成像技术的研究进展,介绍了该类技术的国内外典型应用情况,最后分析了该领域所面临的挑战及进一步发展方向和应用前景。

一种基于幅度相位信息辅助的多假设跟踪算法

传统多目标跟踪算法在距离拖引(Range Gate Pull Off,RGPO)干扰场景中,由于无法有效区分真实目标和干扰,将出现目标航迹起始错误、跟踪误差增大、跟踪中断等现象,严重影响跟踪性能。针对这一问题,基于雷达量测的幅度和相位特征提出一种信息辅助多假设跟踪(Information Assisted Multiple Hypothesis Tracking,IA-MHT)算法。IA-MHT算法利用了幅度、相位信息区分目标真实量测和虚假量测,并基于判别结果修正了全局联合假设概率和航迹得分的计算步骤,从而提高算法的抗杂波和抗干扰性能。在RGPO干扰场景中的仿真结果表明,IA-MHT算法能够有效区分干扰量测,获得优于传统MHT算法的数据关联性能。

初相捷变波形优化设计与信号处理方法研究

捷变波形具备一定的距离和速度模糊抑制能力,同时兼具优良的低截获和抗干扰性能,为雷达系统提供了新的信号处理维度。初相捷变波形相对简单,工程实现难度小,为实现波形设计和信号处理闭环,本文开展了初相捷变波形优化设计与信号处理方法研究。首先,介绍了初相捷变波形的距离选通特性,进而构建了基于距离选通特性的初相捷变波形优化设计模型,并通过Majorization-Minimization算法和牛顿法进行求解。所提算法可采用平方迭代法加快收敛速度,经仿真验证,与随机产生的初相捷变波形相比,所提算法可以显著改善优化后初相捷变波形的距离选通特性。其次,基于初相捷变波形的抗折叠杂波性能,探讨了基于距离选通特性的自适应杂波抑制算法,即利用初相捷变波形空时维导向矢量的距离选通特点,实现分距离段杂波抑制,使得近距主副瓣杂波不会折叠到远距离段,经仿真与实测数据验证,所提算法在强杂波环境下具备良好的远距低速目标探测能力。最后,研究了基于距离选通和交替反演的干扰抑制算法,利用远距支援干扰滞后于目标回波的特点,并基于初相捷变波形的距离选通特性,通过距离段间交替投影实现干扰与目标回波的分距离段重构,经仿真验证,所提算法可以实现对远距支援干扰的有效抑制。

基于距离选通图像的目标检测方法研究

由于距离选通图像缺少颜色特征信息导致检测率低、距离信息特征提取能力较弱等问题,因此,提出了一种基于改进YOLOv8s网络的距离选通图像检测方法。首先,提出自适应选通特征融合模块,对距离选通图像和其深度信息进行特征级融合,获取高级语义信息;其次,采用基于多尺度的深度可分离卷积模块构成的空间注意力模块,对每个特征层进行加权运算,以获得更多的关键特征;最后,改进了Neck部分PAN结构,提高了网络的目标检测能力。在距离选通图像数据集上进行了实验,实验结果表明该方法能有效地提升检测精度,并具有实际应用价值。

独立测距通道超低空无线电引信

针对多通道功能复用脉冲或脉冲多普勒(PD)引信测距误差较大,严重制约引信超低空性能的问题,提出基于独立测距通道的超低空无线电引信。该超低空无线电引信由目标探测通道和独立测距通道组成,其中目标探测通道采用PD体制,独立测距通道采用线性调频连续波(LFMCW)体制。仿真分析结果表明,基于独立测距通道的超低空无线电引信安全距离仅需0.7 m,在目标探测通道距离波门调整过程中引信目标探测区得到最大程度的保留,同时具备3 m高度飞行目标的近距探测能力。

超高重频卫星激光测距时序电路实现及应用

高重频卫星激光测距(Satellite Laser Ranging,SLR)具有精度高、捕获快、观测数据量大、可靠性高等优势。但随着重复频率提升至百千赫兹以上,现有测量时序电路无法达到系统运行处理速度和实时后向散射规避等要求。本文提出超高重频卫星激光测距时序电路设计方法,采用FPGA代替控制计算机进行门控距离实时计算,精确产生门控信号控制探测器开启,并使用了收发交替的方式实时调整激光点火信号以规避后向散射干扰。能够自主完成激光测距中距离门控输出时刻的计算、存储和信号输出,最高工作频率大于500 kHz,满足百千赫兹超高频率测距的要求。该系统已成功应用于上海天文台100 kHz重复率SLR,标准点精度突破200μm,验证了基于FPGA的测距时序电路的正确性和潜力。该电路设计简单、分辨率高、上位机交互方便,为百kHz~MHz的超高重频SLR系统时序控制电路设计提供有效解决方案。

门控激光相机雷达三边滤波平滑去噪算法研究

基于距离能量相关选通三维成像技术的门控激光相机雷达可以同时获取高水平分辨率的强度图像和三维图像,不存在激光雷达和摄像机复合技术方案中的异源数据融合问题。然而,与现有激光雷达一样,门控激光相机雷达输出的选通三维图像依然会受到器件噪声、时域特性、目标反射率和背景环境等因素影响,导致三维图像质量降低,最终影响实际应用,特别是高水平分辨率特点下的小尺度噪声问题。针对门控激光相机雷达小尺度噪声问题,文中提出三边滤波平滑去噪算法,该算法同时利用选通图像和深度图像对三维图像进行平滑。相比传统的双边滤波,该算法引入选通图像的灰度作为第三个权重,当物体边缘与其他物体或背景存在灰度差异时,该算法有很好的边缘保持效果。仿真实验使用两种不同噪声的金字塔靶,并通过双边滤波和三边滤波对噪声进行平滑,对于噪声标准差为0.2 m和0.3 m的金字塔,三边滤波后三维图像的峰值信噪比分别平均提高10.81 dB和6.76 dB。在物理实验中,对于含有噪声的标准靶,三边滤波后峰值信噪比平均提高8.47 dB。最后采集了真实复杂场景的选通图像,完成小尺度噪声的平滑和大尺度噪声的去除,验证了三边滤波结合统计学滤波方法的实用性。

不同水质下光学偏振对距离选通成像目标识别距离的影响分析

水下光学成像技术对于海底资源勘测、海洋生态监测、水下搜索救援、水下考古等应用具有重要意义。相比传统水下摄像机,距离选通成像技术可以过滤选通切片外的后向散射噪声和环境背景噪声,实现高质量水下成像,但是在浑浊水体中仍然会受切片内后向散射噪声影响,导致成像距离缩短。对此,开展了光学偏振与距离选通成像结合的水下偏振选通成像技术研究,利用后向散射光良好的保偏性去除选通切片范围内的后向散射噪声,提升目标识别距离。通过理论仿真和实验研究,对比分析了不同水质下距离选通成像和偏振选通成像目标识别距离的差异。发现存在临界衰减系数c0:当水体衰减系数小于等于c0时,光学偏振对于提升距离选通成像工作距离无效果;当水体衰减系数大于c0时,偏振可提升距离选通成像工作距离。实验中还发现,目标反射率会影响临界衰减系数。该研究有利于不同水质下距离选通成像的优化应用。

基于脉间码型捷变波形的距离-多普勒二维干扰重构算法

密集假目标干扰通过在真实目标周围产生大量假目标,形成欺骗和压制双重干扰效果,严重影响雷达的目标探测能力。为此,该文提出一种基于脉间码型捷变波形的距离-多普勒二维干扰重构算法来抑制密集假目标干扰。该算法基于脉间码型捷变波形的距离选通性,在距离-多普勒域通过交替反演实现干扰和目标重构,并从回波中对消干扰来实现干扰剔除。首先,通过构造不同距离段的接收滤波器组来实现干扰和目标回波的分距离段处理;其次,采用联合失配滤波器组使各脉冲滤波输出的距离旁瓣结构近似相同,减小脉间码型捷变波形经脉冲多普勒处理后沿多普勒维的散布能量;然后,利用干扰和目标回波在不同距离-多普勒平面上的能量分布特性构造滤波矩阵;最后,通过交替反演实现干扰和目标的精准重构,进而实现密集假目标干扰的抑制。仿真结果表明,与传统方法相比,该文所提算法在干扰抑制和运行时间方面展现出优越的性能,显著提升了雷达在强干扰环境中的目标检测能力。

视觉引导的激光距离选通三维成像

由于可以抑制后向散射,距离选通三维成像在雾、雨、雪等恶劣天气下的远距离探测中展现出巨大潜力。传统方法利用光学成像机理建模实现,发展成熟,但存在性能依赖于硬件特性、系统灵活性差等问题;基于学习的方法克服了传统方法的硬件限制,但是未考虑选通图像特点,导致精度有限。针对上述问题,提出一种融合注意力机制的视觉引导方法,该方法从视觉层面出发,针对物体轮廓、纹理较弱等区域着重计算区域权重,提高区域预测精度;结合一种激光雷达深度补全算法,获得稠密深度真值图像用于模型监督,从而提升模型深度估计精度。实验结果表明,对比现有最先进的方法,在夜晚数据中平均绝对误差(Mean Absolute Error,MAE)提升了6.3%,均方根误差(Root Mean Square Error,RMSE)提升了2.3%,并在雾、雪天场景下得到更清晰的目标轮廓。

基于匈牙利概率数据互联的抗RGPO干扰跟踪方法

针对受距离门拖引(RGPO)干扰导致的雷达跟踪误差增大、航迹中断概率变高等问题,提出基于匈牙利概率数据互联的抗RGPO干扰跟踪方法。首先,分析RGPO干扰和雷达跟踪原理,将雷达抗干扰跟踪问题建模为邻近多目标跟踪问题。然后,设计假目标虚拟航迹起始算法,并在概率数据互联框架下引入匈牙利算法进行真假航迹交互修正,有效解决抗干扰跟踪时点迹-航迹错误关联、滤波发散等问题。最后,理论分析和仿真结果表明,与传统方法相比,所提方法在未受干扰时雷达跟踪性能保持不变,在受RGPO干扰时可有效提升目标跟踪精度、大幅降低航迹中断概率。

一种改进的激光距离选通成像系统

距离选通技术是克服激光后向散射,提高激光距离选通成像系统信噪比的有效方法。阐述了激光距离选通成像原理,详细分析了距离选通关键技术,指出了传统的距离选通同步控制方案的缺点,提出了一种改进的激光距离选通成像系统,讨论了激光距离选通成像系统今后需要重点研究的课题和发展趋势。