IMM迭代扩展卡尔曼粒子滤波跟踪算法

该文提出了一种交互式多模型(IMM)迭代扩展卡尔曼粒子滤波机动目标跟踪算法。该算法在多模型中使用了改进的粒子滤波器,通过对迭代扩展卡尔曼滤波(IEKF)的测量更新按照高斯牛顿方法进行修正,减小了非线性滤波带来的线性化误差,然后利用修正的IEKF来产生粒子滤波的重要性密度函数,使其融入最新观测信息。最后将所提算法与交互式多模型粒子滤波(IMMPF)进行了比较,仿真结果表明该算法具有更好的跟踪性能。     

多模型粒子滤波在机动目标跟踪中的应用

针对在非线性机动目标跟踪中存在的滤波器易发散,跟踪误差大等问题,在双机协同跟踪的基础上,提出了利用交互式多模型粒子滤波(IMMPF)对空中机动目标进行跟踪的算法。该算法将粒子滤波和交互多模型有效结合,基本解决了非线性机动目标跟踪中存在的问题。通过仿真表明,与扩展卡尔曼滤波(EKF)和交互式模型扩展卡尔曼滤波(IMMEKF)相比,IMMPF能够降低跟踪误差,提高收敛速度,且有很强的鲁棒性。     

基于IMM-极限迭代UFIR的机动目标跟踪算法

为提高非高斯噪声条件下机动目标跟踪的精度,提出基于交互式多模型极限迭代无偏有限脉冲响应滤波(IMM-极限迭代UFIR)算法。采用对噪声统计特性不敏感的极限迭代无偏有限脉冲响应滤波(UFIR)作为其子滤波器,对各模型进行状态估计,最后通过对各模型的输出结果综合得到机动目标状态。仿真结果表明,在噪声条件复杂的情况下,该算法比交互式多模型卡尔曼滤波(IMM-KF)具有更高的跟踪精度和稳定性,计算量小于IMM-PF,算法能较好地兼顾跟踪精度和计算量两方面性能。     

红外搜索跟踪系统对机动目标的跟踪算法研究

红外搜索跟踪系统(IRST)只能得到目标的角度,目标的精确三维运动方程难以建立,因此对机动目标进行跟踪尤为困难.提出了适合红外搜索跟踪系统的纯角度交互式多模型(IMM)定向跟踪算法,并和基于单一模型的卡尔曼滤波做了仿真对比,仿真结果表明了所提出的算法较卡尔曼滤波在性能上有很大提高,能够很好地跟踪机动目标.     

卡尔曼滤波在坦克目标跟踪中的应用

目前对飞机、导弹等高速、高机动目标跟踪的卡尔曼滤波算法取得了丰硕成果,但对相对低速、机动性能弱的坦克目标实施跟踪的算法研究较少。本文结合坦克机动特点,着重设计了恒速运动和恒加速运动模型,提出运用交互式多模型卡尔曼滤波算法对其实施跟踪,并进行了仿真实验和结果分析。     

基于高斯-艾肯特滤波的机动目标跟踪算法

针对交互式多模型(IMM)算法切换滤波模型缓慢、跟踪精度低甚至发散的问题,提出了在机动目标跟踪中使用的高斯-艾肯特滤波算法。首先,该算法确定观测模型和滤波模型集,分别构造量测方程组和滤波方程组,形成总体观测矩阵;然后,针对跟踪目标的非合作机动,提出使用卡方检验来检验滤波效果,并通过滤波控制算法实时调整滤波内存长度,使用高斯-艾肯特滤波对机动目标跟踪具有很强的灵活性,实现自适应跟踪;最后,在目标跟踪仿真中与三种改进模型集的卡尔曼滤波IMM算法进行对比验证,对两类算法进行了复杂度分析。仿真结果证明了高斯-艾肯特滤波算法的有效性,在无先验信息条件下拥有更高的跟踪精度。     

变维自适应交互式多模型跟踪算法

针对传统的交互式多模型(IMM)算法通常采用相同维数的模型进行滤波,存在较大的模型误差以及当前统计模型(CS)中的参数需要合理设定的问题,提出一种变维自适应交互式多模型(AIMM)跟踪算法。该算法首先利用维数变换,将不同维数的模型转换为统一的维数进行交互滤波,使之适用于一般的机动目标,减少模型跟踪误差;然后通过引入由残差信息定义的调整因子对CS模型中的参数自适应调整,提高模型与实际运动模式的匹配程度;最后将参数调整后的CS模型反馈到变维IMM算法中,来改善跟踪性能。仿真实验表明,与传统变维IMM算法相比,文中所提算法在有效跟踪机动目标的同时,提高了目标的跟踪精度。     

基于IMM-SCKF-STF的机动目标跟踪算法

在处理非线性机动目标跟踪问题时,传统的非线性滤波估计算法跟踪误差大且容易引起滤波发散.针对上述问题,研究将强跟踪平方根容积卡尔曼滤波(SCKF-STF)和交互多模型(IMM)算法相结合,提出一种新型的交互多模型强跟踪平方根容积卡尔曼滤波(IMM-SCKF-STF)跟踪算法.该算法在SCKF基础上引入强跟踪渐消因子,使其不仅拥有应对机动目标状态突变的强跟踪能力,同时还具备交互多模型算法的优良机动目标跟踪性能.因此,新算法在机动目标跟踪方面将获得更高的非线性滤波估计精度,且算法的稳定性和应对状态突变的跟踪鲁棒性能获得显著提高.最后,通过两个仿真例子验证了此算法的有效性与优越性.     

多站无源跟踪边缘化卡尔曼滤波算法

多站无源跟踪量测方程非线性强,对跟踪算法的稳定性及精度提出了更高的要求。为实现稳定高精度跟踪,提出了新的基于边缘化卡尔曼滤波（MKF）的多机无源跟踪算法。该算法将非线性的量测方程表示为p阶Hermite多项式的加权和,将加权矩阵的先验分布建模为高斯过程,求得其后验分布后对其进行积分来消除加权矩阵的影响,最终可得对状态及其协方差矩阵估计的闭式解。以只测角跟踪为例对所提算法性能进行验证,仿真结果表明,相对于扩展卡尔曼滤波（EKF）算法、不敏卡尔曼滤波（UKF）算法及容积卡尔曼滤波（CKF）算法,所提算法具有更好的跟踪性能。      

基于IMMCKF的机动目标跟踪算法

针对非线性机动目标跟踪中滤波器易发散、跟踪精度低等问题,将容积卡尔曼滤波器(CKF)引入到交互式多模型算法(IMM)中,设计了交互式多模型容积卡尔曼滤波算法(IMMCKF)。该算法采用Markov过程描述多个目标模型间的切换,利用CKF滤波器对每个模型进行滤波,将各滤波器状态输出的概率加权融合作为IMMCKF的输出。仿真结果表明,与IMMUKF算法相比,IMMCKF算法跟踪精度更高,模型切换速度更快,计算量更小,该算法具有重要的工程应用价值。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.