空间目标的地基红外辐射特性测量技术研究

提出了一种基于望远镜内部定标黑体与大气层外已知光谱特性的红外自然星体作为参照基准的地基大口径望远镜联合定标方法,在此基础上建立了相应的辐射度测量数学模型,以实现对空间目标的高精度红外辐射特性测量。内部定标黑体用于得到大口径望远镜后半光路系统对应探测器的各个像元响应度,外部标准红外自然星体用于估算大气层外目标附近大气与望远镜前半光路系统的等效透射率。在地基1.2m口径望远镜上对大量特性已知的红外自然星体辐射强度测量实验表明,当目标附近具有较强能量红外参考星情况下,如红外参考星在3~5μm波段大气层外辐照度高于1×1016 W/cm2量级,目标红外辐射强度测量不确定度能够优于15%。该方法能够克服大气程辐射、消光及高质量大口径辐射定标源对大气层外目标红外辐射强度测量不确定度的影响,适合于地基大口径望远镜红外光电测量系统的辐射定标与大气层外空间目标红外辐射特性高精度测量。     

红外烟幕干扰材料的制备与性能研究

烟幕具有"隐真"和"示假"双重功能,是一种重要的对抗技术。红外烟幕干扰材料是近几年重点发展的烟幕材料之一,红外吸收陶瓷材料是一种对红外线具有高吸收率的无机材料。本文以SiO2、Al2O3、MgCO3、TiO2等为原料,利用高温烧制的方法,制备出了对8～14μm波长红外光具有很好遮蔽效果的陶瓷烟幕干扰剂材料。研究结果表明,当该陶瓷烟幕干扰剂材料的平均粒径d50为4.2μm时,既具有很好的遮蔽效果,遮蔽率≥85%(透过率≤15%),又具有较长的持续遮蔽时间。同时还有良好的热稳定性和储存性能。     

随机取向烟幕凝聚粒子的消光特性

采用蒙特卡罗方法根据团簇-团簇凝聚(CCA)模型对由球形原始微粒凝聚而成的烟幕凝聚粒子进行模拟,用离散偶极子近似(DDA)方法研究随机取向烟幕凝聚粒子的消光特性.结果表明,凝聚粒子的消光特性受到原始微粒数量以及粒径的影响,粒子的凝聚将减弱烟幕的消光性能;当凝聚结构中原始微粒的数目一定时,存在使烟幕消光性能达到最大的原始微粒粒径.     

燃烧型发烟剂红外光谱特性专家系统的研究

为了实现燃烧型抗红外发烟剂配方的快速筛选,文章在基于最小自由能法的烟火药燃烧产物预测模型的基础上,设计了燃烧产物推理机,建立了燃烧型发烟剂光谱特性专家系统,研究了利用专家系统进行发烟剂配方快速筛选的可行性。在用户输入发烟剂配方后,专家系统能够计算出发烟剂的燃烧产物及其含量,然后利用红外加谱技术,对各产物红外谱图进行加合,模拟出烟幕的红外谱图,进而利用面积积分法,预测出烟幕在3～5 μm和8～14 μm的遮蔽指数。文章使用FTIR光谱仪对一种HC型发烟剂进行了测试,结果表明,专家系统的计算产物与实际产物相吻合,遮蔽指数预测值与发烟剂的实际测试表现一致,为燃烧型发烟剂配方的快速筛选提供了一种新方法。     

基于RGB色彩模式的彩色烟幕遮蔽效果测量方法

介绍了烟幕的类型和使用方式,分析了喷射式彩色烟幕的遮蔽原理。根据三基色原理提出了采用RGB色彩模式测量评估彩色烟幕色度的方法。分析了目前普遍采用的衰减率数据矩阵插值法测量烟幕形成时间的方法以及该方法在使用中存在的误差因素,提出采用彩色烟幕RGB数据矩阵法测量评估彩色烟幕形成时间的新方法,该方法解决了由烟幕的形状及形成方式、目标的数量及布设方式等因素引起的系统误差,经分析该方法对喷射式烟幕形成时间的测量精度提高到90%以上,具有测量精度高、便于数据处理的优点,丰富了烟幕遮蔽效果测量的评估措施。     

烟幕对成像跟踪干扰效能外场试验测量

利用发烟源结合外场运动目标,构建典型条件下的外场烟幕测量试验,通过多光谱成像传感器采集数据,验证和修正该类型烟幕的消光模型。并且通过采用典型跟踪算法的专用成像跟踪器,测量各种烟幕施放条件下干扰目标得到的跟踪误差。试验数据经过分析及与烟幕经典理论计算方法对比,得到了其干扰效能规律,为该类烟幕的使用和对成像传感器干扰效果提供了可靠的依据。     

红外烟幕遮蔽率及其分布表征方法

目标与背景的辐射对比度是红外系统探测目标的主要依据,也是烟幕干扰重点降低的一个参量。结合辐射对比度的定义和红外定标原理,由目标和背景的视在辐射亮度引入其视在辐射对比度,并与目标和背景热像图的灰度值关联起来。利用烟幕遮蔽前后与目标和背景视在辐射对比度变化相对应的热像灰度对比度的变化,对烟幕遮蔽率进行表征。用提出的背景灰度方法对干扰实验结果进行了表征,计算得到3组试验的背景灰度值分别为91.902 4、88.002 0、33.285 6,并获得了目标区域各像元遮蔽率的直观分布图,克服了以往以点代面的评价方法。     

基于红外偏振特性的空间目标探测可行性探讨

红外偏振特性及其变化规律能够表征空间目标的表面信息与状态信息。结合当前偏振探测的最新进展,分析了基于红外偏振特性对空间目标进行探测的思路与可行性。由于空间目标偏振特性会随空间目标特定的材料以及运动轨道不同而存在差异,因此红外偏振探测技术可以为空间目标的探测和识别提供更多的依据。通过对空间目标常用的不同材料、同一材料不同表面状态以及在不同观测角下偏振特性的分析,得出光滑钢板红外平均偏振度是粗糙钢板的1.3倍左右。     

空间目标红外辐射理论计算

建立了空间目标的热平衡方程,利用节点网络法求解其表面温度场分布;然后利用普朗克公式计算了空间目标的红外辐射强度;最后对大气层外某空间目标的表面温度场分布和红外辐射强度分布进行了数值计算。     

烟幕干扰的建模与仿真

阐述了舰用遮蔽式烟幕干扰的工作机理,对典型舰用遮蔽式烟幕干扰进行了数学模拟仿真,建立了舰艇、烟幕、导弹的数学模型,提出了干扰评估准则,给出了仿真流程图.并对多次仿真结果进行了统计分析,获得了烟幕弹战斗使用的一般规律.     

GPU-accelerated real-time IR smoke screen simulation and assessment of its obscuration

With the growing demand for the Battlefield Environment Simulation (BES), IR smoke screen, which is computationally expensive and absolutely indispensable, should be modeled true to life and correct in its thermal radiation characteristics. This paper analyzes the features of an IR smoke screen, and represents an IR smoke screen model based on light extinction, particle dispersion and temperature attenuation, which is calculated by GPU and rendered to screen in real time. Thus a method considering both the real-life in profile and the real-time in efficiency is presented. Additionally, the comparison between the simulated results and the measured data is made to verify the correctness of the smoke screen’s obscuration, which illustrates the effect of its interference feature in an infrared scene.     

红外光幕靶测速系统和精度分析

介绍了弹丸初速度测量的不同方法;讨论了红外光幕靶的测速原理;分析了该系统的测速误差;由实弹射击试验证明:红外光幕靶测速系统达到小于 0.1%的测速精度.     

Brownian motion and correlation in particle image velocimetry

In particle image velocimetry applications involving either low velocities or small seed particles, Brownian motion can be significant. This paper addresses the effects of Brownian motion. First, general equations describing cross-correlation particle image velocimetry are derived that include Brownian motion. When light-sheet illumination particle image velocimetry (PIV) is used Brownian motion diminishes the signal strength. A parameter describing this effect is introduced, and a weighting function describing the contribution to the measured velocity as a function of position is derived. The latter is unaffected by Brownian motion. Microscopic PIV Brownian motion also diminishes the signal strength. The weighting function for microscopic PIV is found to depend on Brownian motion, thus affecting an important experimental parameter, the depth of correlation. For both light-sheet illumination and microscopic PIV, a major consequence of Brownian motion is the spreading of the correlation signal peak. Because the magnitude of the spreading is dependent on temperature, PIV can, in principle, be used to simultaneously measure velocity and temperature. The location of the signal peak provides the velocity data, while the spreading of the peak yields temperature.     

Discrimination of Smoke Particles Using Infrared Photoelectrical Detection

A method of discrimination of smoke particles using infrared photoelectrical detection is proposed in this paper. Principle of the method is that smoke particles of different materials have different scattering light intensities at same scattering angle according to Mie Theory. Facility used to realize the method includes an infrared laser as light source and an array of avalanche photodiodes distributed at assigned angles as sensing devices. Scattered light signal at these angles are collected and processed. Categories of smoke particle are discriminated by signal processing results. Experiments show that by using this method cigarette smoke, kerosene smoke and water vapor can be discriminated with rate of discrimination of greater than 95%. Application of this technology in the field of fire detection will eliminate some effects of human activities such as cigarette smoking and steam on smoke detection, and improve sensitivity as well as reliability of smoke detection.     

纳米碳纤维红外消光数值计算

为探讨纳米碳纤维作为烟幕粒子的红外消光特性,基于电磁场理论建立了细直的纳米碳纤维感应电流积分方程,并利用矩量法进行了求解,导出了纳米碳纤维散射场及吸收、散射和消光截面的计算式.通过与变分法的计算结果相比较,表明了该方法的有效性.利用该方法数值分析了纳米碳纤维红外消光截面与入射场波长、入射角、纤维长度和半径的关系,计算结果为纳米碳纤维用于红外烟幕干扰提供了理论依据.     

激光在烟幕中传输的蒙特卡罗模拟

建立蒙特卡罗计算模型,模拟计算1.06μm脉冲激光在石墨烟幕中的传输.分析透过率与石墨粒子粒径、烟幕浓度、烟幕厚度的关系,用卷积方法计算一定宽度的脉冲激光穿过烟幕后的波形,数值仿真δ脉冲和矩形脉冲激光在各种石墨烟幕中的时间展宽特性.模拟结果表明:石墨粒子存在一最佳半径(0.16μm),该半径的石墨粒子烟幕不仅使激光能量衰减最强,而且产生的时间展宽也最显著;激光脉冲宽度越小,其波形变化和时间展宽越显著,微秒量级脉宽的激光脉冲穿过烟幕后波形变化和时间展宽效应不明显.     

Infrared surface modes in small NiO particles

Small particle specimens of NiO (powder and arc-produced smoke) were studied using infrared spectroscopy. Size distribution and particle configuration were established using an electron microscope. The importance of surface modes (polaritons) as well as their dependence on particle shape was established in the interpretation of the spectra. Chain formation in the smoke suggested cylinder calculations which showed the presence of both bulk and surface modes, in agreement with measurements. In both samples particle shape effects broaden the spectral features in the vicinity of the surface mode. Because of large errors in calculating surface modes from optical constants derived from a diatomic model, it was also shown that accurately measured optical constants are required in the study of the surface mode problem.