一种采用干涉仪测量光电稳瞄系统稳定精度的方法研究

为了满足未来高精度光电稳瞄系统rad级稳定精度的测试需求,提出一种基于干涉仪测量的稳定精度测试方法。基于泰曼格林干涉仪中同源两光束光程差对干涉条纹的影响,利用CCD观察干涉条纹的微小变化,实现稳定精度测试。采用该测试方法对快速转向镜（fast steering mirror,FSM）的指向精度和某型光电稳瞄产品稳定精度进行了测试研究,结果表明,该方法对稳定精度的测量精度可以达到0.2 rad。     

机载光电稳瞄平台减振技术研究北大核心CSCD

机载光电稳瞄平台受飞机作战环境的干扰因素,会引起设备环架的振动,对光电平台载荷视轴的稳定性及跟踪精度影响很大,减振的主要任务是有效隔离环境振动。与传统橡胶减振器比较,文章提出了一种新型机载光电稳瞄平台的柔性减振设计。并通过ANSYS仿真软件对新的减振模型进行了模态仿真分析,通过振动试验对设计的性能进行了有效评估,测试结果与仿真评估误差为0.56%,说明该设计对机载光电稳瞄平台具有减振性。     

光电稳瞄系统装调的关键技术

鉴于光电稳瞄系统的复杂性和科研开发的不可预见性，传统装调技术远不能满足产品科研设计发展的需求。着重分析探讨了光电稳瞄系统中各探测器光谱范围的差异性、光学平台结构的复杂性、光学轴系与回转轴系的一致性带来的精度难以实现的关键技术问题。通过多组自准直仪架设空间过渡基准，采用特定的大口径光轴调校装置，解决了光轴平行性调校问题。以调校光学轴系与机械回转系统的同步精度为出发点,确定了各部件之间的装配及装配误差的影响。通过设计的方位/俯仰天顶测量仪，解决了回转轴系正交性精度调校难题，实现了传统工艺方法和普通调校装置无法达到的设计指标和精度要求。     

光电稳瞄平台用减振器

设计合理的减振器可以有效地隔离光电稳瞄平台工作环境中的振动，从而保证使用精度。本文通过对橡胶减振器和金属三向减振器的工作原理及减振性能的对比，为减振器的设计提供了参考依据。     

机载稳瞄控制系统模型及仿真分析

瞄准线高精度稳定是机载光电稳瞄系统的主要指标和关键技术。根据四框架稳瞄系统的工作原理，以手动跟踪模式为主要研究对象，建立了稳瞄伺服控制系统模型。考虑到直升机扰动特点，对线扰动、角速率扰动、摩擦力矩、弹性力矩等各种扰动因素也建立相应的数学模型，同时在各种扰动因素作用下利用Matlab对机载高精度稳瞄系统的手动跟踪控制模式进行了仿真设计分析和理论研究，设计出适合的控制器。此模型在实际系统中获得验证，对稳瞄伺服控制系统的设计具有参考意义。     

惯性寻北/稳瞄组合技术及仿真

本文提出一种用于坦克等陆用战车的自寻北／稳瞄组合平台新方案。该方案利用稍加改进的二自由度瞄准线稳定平台和采用双位置计算罗经法进行建立经，使一个平台同时兼有寻北、稳瞄双重功能。     

光电稳瞄二级稳定系统性能分析及测试

为了对控制系统稳定性能和扰动隔离能力进行分析,对二级稳定系统进行了建模和控制器设计,仿真结果显示,系统速率稳定回路带宽提升至200 Hz,1 Hz位置隔离度提升至-90.1 dB。在实际系统中,采用位置敏感探测器（PSD）测量瞄准线的运动,隔离度测试实验结果显示1 Hz位置隔离度提升至-73.1 dB,提升约20 dB,测试结果证明:二级稳定技术能够显著提高系统的稳定精度。     

光电稳瞄二级稳定系统性能分析及测试

为了对控制系统稳定性能和扰动隔离能力进行分析,对二级稳定系统进行了建模和控制器设计,仿真结果显示,系统速率稳定回路带宽提升至200 Hz,1 Hz位置隔离度提升至-901 dB。在实际系统中,采用位置敏感探测器(PSD)测量瞄准线的运动,隔离度测试实验结果显示1 Hz位置隔离度提升至-731 dB,提升约20 dB,测试结果证明:二级稳定技术能够显著提高系统的稳定精度。     

机载光电稳瞄系统实时被动测距方法研究

针对现有直升机机载光电稳瞄系统高精度角度测量和角速率测量的特点,提出一种利用测量目标相对角度和角度变化率等参数实现目标实时被动测距的方法。建立了机载稳瞄平台对地面固定目标定位的数学模型,提出利用系统旋转变压器测量目标角度,利用惯性速率陀螺测量目标角度变化率。该方法使得目标角度变化率的测量精度(优于0.1 mrad/s)比一般光学方法提高了一个数量级。利用扩展卡耳曼滤波(EKF)算法提高目标距离估算精度,保证测量结果的稳定性。理论仿真和外场验证实验结果表明,该方法可以实时估算目标相对载机的距离,适合于武装直升机快速实时目标定位。     

稳瞄惯导周视观瞄镜的设计

介绍一种中精度、低成本周视观瞄镜的设计方法，其特点是用一个机械陀螺同时实现稳瞄和惯导2项功能。利用陀螺罗经原理，使机械陀螺的敏感轴快速收敛于子午面和水平面的交线上，并借助陀螺定轴性和2自由度环架，使陀螺隔离运动载体的扰动；通过环架上的光电传感器测出运动载体的姿态角，使观瞄镜的瞄准线随动于陀螺的敏感轴，实现间接稳定。在瞄准过程中，瞄准线的调转指令以随动修正量的形式加入，通过姿态矩阵的解算，可获得运动载体扰动量沿稳瞄坐标轴方向的投影，即瞄准线随动陀螺轴的输入量。最后综合运动载体的姿态和里程计信息，可以实现导航功能。     

基于Matlab的非线性动力学系统分析

利用Matlab软件对洛仑兹和达芬2个典型的非线性动力学系统进行了较为详细的分析．在使学生初步掌握了如何使用Matlab软件解决数值分析中的一些计算问题和绘图问题的同时．也使学生对非线性动力学系统的运动本质有一定的认识．     

Noise analysis of an electro-optic sensor system

Optical Review - This paper describes the noise analysis of an electro-optic (EO) sensor system based on experimental and simulation results. We developed a polarization simulator of the EO sensor...     

Failure diagnosis of organic photovoltaic using electro-optic probe

This paper describes the measurement of an organic photovoltaic using an electro-optic probe. We verify the validity of the electro-optic probe by comparing it with a conventional electric probe. The electric field distribution of the organic photovoltaic is examined on the basis of results of the test board measurement using the electro-optic probe and results of the test board simulation using an electromagnetic field simulator. We succeed in failure diagnosis of the organic photovoltaic in three failure modes. We found that the organic photovoltaic has a failure cell, and the electro-optic probe is successfully applied to failure diagnosis of organic photovoltaic.     

机载光电观瞄系统的瞄准线指向线性运动补偿方法

为方便操作员快速捕捉并瞄准目标,提出一种适用于机载光电观瞄系统的线性运动补偿方法。该方法借助地面目标相对载机在初始东北天坐标系下的速度矢量进行分解,得出目标相对光电系统在惯性坐标下的角速度,并根据解算出的角速度值实时进行伺服补偿,驱动光电转塔于手动模式下,当操作员不操控光电转塔时,系统的瞄准线能够自动地指向地面目标区域。该方法已在某型无人机用光电观瞄系统挂飞试验中进行了验证,结果表明:在电视观瞄具的小视场（0.70.5）下,地面目标点、瞄准线指向点相对载机点的张角在方位和俯仰方向均小于该视场的1/6。     

Non-destructive evaluation of materials at high temperatures using electro-optic holography

An electro-optic holographic technique for the non-destructive evaluation of materials at high temperatures is presented. The test object is heated in an oven that can attain a temperature of 1000 °C. Electro-optic holography is used for the real-time visualization of full field in-plane displacement fringes. Digital image processing techniques are used for the analysis of fringes. Some of the problems encountered, while recording interferograms at high temperatures, are discussed. The technique is employed for the measurement of in-plane strains, in a disc of a super alloy, subjected to diametral compression, at 1000 °C.     

Frequency comb stabilization with bandwidth beyond the limit of gain lifetime by an intracavity graphene electro-optic modulator

Intracavity loss modulation enables offset-frequency control with bandwidths beyond what is possible by pump power modulation. To demonstrate this new method, we use a subwavelength thick graphene electro-optic modulator to stabilize the offset frequency in a Tm:fiber frequency comb at 1.95?μm wavelength. Record-low residual phase noise of 144?mrads was achieved with this new locking scheme.     

Time-resolved,hot-electron conductivity measurement using an electro-optic sampling technique

A picosecond electro-optical sampling technique has, for the first time, been used for measuring the high-electrical-field instabilities in a semiconductor. Current-voltage-characteristics and the high-field domain nucleation time for n-type In_0.53 Ga_0.47 As samples have been measured with a time resolution better than 10 ps and compared with existing theoretical calculations.     

Photonic ultrawideband monocycle pulse generation using a single electro-optic modulator

A compact approach to photonic-assisted ultrawideband (UWB) monocycle pulse generation is proposed and experimentally demonstrated based on the wavelength dependence of the half-wave voltage of a Mach-Zehnder modulator (MZM). By employing a single MZM with dual-wavelength injection at around 1310 and 1550 nm, a pair of polarity-reversed monocycle pulses with the full width at half-maximum of about 80 ps and the fractional bandwidth of greater than 160% can be generated. The experiment results agree well with the theoretical prediction. The simple setup and the convenience to control the monocycle pulse polarity are favorable for future applications.     

Optimal crystal geometry and orientation in electric field sensing using electro-optic sensors

For optimal sensitivity in electric field measurements, electro-optic (EO) crystals are typically selected based on their EO coefficients and dielectric constants. However, the conventional figure of merit yields sensitivity predictions regarding EO materials that are inconsistent with experimental data. In this Letter, we demonstrate that depolarization effects, which are often ignored, can dramatically enhance responsivity depending on the shape and orientation of the EO crystal. For optimal sensitivity, these effects are best exploited in longitudinal EO sensors, where they yield an optical modulation depth that increases quadratically with crystal length.