基于DP-TBD的分布式异步迭代滤波融合算法研究

该文主要运用检测前跟踪动态规划(Dynamic Programming-Track Before Detect)算法解决目标跟踪问题。动态规划(Dynamic Programming, DP)是一种通过对量测空间栅格化处理,然后对离散的量测空间中所有可能的物理路径进行遍历的算法。然而,该算法提供的是一种未经滤波和平滑的点迹序列。随着实际战争环境日益复杂,基于单雷达的DP-TBD算法在信噪比(SNR)较低时跟踪效果不佳。此外,由于DP-TBD算法没有状态误差协方差矩阵,因此无法将不同雷达的点迹序列进行融合。而且由于通信时延和不同的采样周期,不同雷达的数据往往是异步的。为了解决以上问题,该文提出了一种基于DP-TBD的分布式异步迭代滤波融合算法(DynamicProgramming?Fuison, DPF)。该算法分为两步,第1步提出了一种迭代滤波方法对DP点迹进行处理;第2步将不同雷达获得的异步状态估计转化为同步的,接着利用几种分布式的融合方法来获取融合之后的状态估计。仿真结果说明,和单雷达相比,该融合算法可以有效提升目标跟踪的性能,同时,该算法也可以降低航迹丢失率和计算量。      

基于DP-TBD 的不同分辨率传感器集中式异步融合算法

主要运用检测前跟踪动态规划(DP-TBD)算法解决不同分辨率的多传感器多目标融合问题,提出了一种基于DP-TBD的不同分辨率的传感器集中式异步融合算法。该算法分为两步:第一步将不同分辨率的传感器取得的回波数据统一对齐到相同单元格尺寸的量测空间;第二步将具有不同采样间隔的传感器得到的量测数据按照时间顺序传送至融合中心进行集中式融合。接着,用动态规划检测前跟踪算法来处理所得到的数据,并且进行航迹恢复。同时,为了提高异步融合的有效性,文中还提出了一种基于变转移状态数的算法。仿真结果说明基于DP-TBD的集中式异步融合算法的有效性,并且和单个传感器的性能比较,该算法大大改善了目标跟踪的性能。     

一类分布式传感器粒子滤波融合算法

针对非线性非高斯的分布式多传感器状态估计问题,提出了一种基于无迹卡尔曼滤波与粒子滤波相结合的融合跟踪算法。通过对量测方程的非线性分析,利用改进的粒子滤波算法(UPF)计算局部传感器的状态估计值,再应用分布式加权融合准则得到全局状态估值.     

分布式雷达目标位置数据融合算法

本文提出了一种使用分布式多部雷达对单个目标进行定位的融合算法,给出了雷达信息系统中目标异步航迹数据的时间校正和坐标转换方法,推导了基于最小方差的最优融合算法公式,得出融合估计的方差比任一个单传感器的方差都小,从而提高了目标点迹融合的精确度,为进一步解决雷达信息系统中多传感器、多目标航迹融合打下了基础。     

一种无格点动态规划检测前跟踪算法研究

目标的多样化和环境的复杂化,对现代雷达的探测能力与航迹处理提出了更高的要求。随着雷达技术的迅速发展, 弱目标的检测与跟踪也受到了更为广泛的关注。检测前跟踪技术可以减少虚假航迹,提高微弱目标的检测和跟踪性能。为改善传统的基于动态规划的检测前跟踪算法计算复杂的缺点,提出了一种无格点DP-TBD改进算法,分析了适用模型, 给出了运动及量测模型。仿真实验表明,该算法具有较好的检测跟踪性能。     

组网雷达多帧检测前跟踪算法研究

组网雷达系统(NRS)由于其稳健的性能优势,在近年来受到了广泛关注。目前,组网雷达系统在进行目标探测时常采用先检测后跟踪(DBT)算法,即在每个时刻先对接收到的回波数据进行单帧门限检测,得到疑似目标的点迹集合,然后上传这些点迹或由这些点迹跟踪得到的航迹估计到融合中心做进一步处理,最终得到全局估计结果。然而,当信噪比(SNR)比较低时,目标往往很难通过单帧门限检测,最终导致目标漏检、航迹起批难,无法有效发挥组网雷达系统优势。针对这一问题,该文提出了一种组网雷达多帧检测前跟踪(MF-TBD)算法。该方法首先在本地节点进行多帧检测前跟踪,然后传递检测得到的点迹序列到融合中心进行融合。该方法一方面利用了组网雷达系统平台优势;另一方面不同于常规先检测后跟踪技术,多帧检测前跟踪能够利用目标空时相关性积累目标能量,改善弱小目标检测性能;因此其可以有效提高系统对目标的检测性能。但是,多帧检测前跟踪输出结果和先检测后跟踪算法不同,导致现有融合方法不适用。针对这一问题,该文首先理论推导了点迹序列的融合方法,然后结合实际雷达模型给出了算法实现流程,最后提出了算法的粒子滤波实现方式并通过仿真实验验证了算法的性能。仿真结果证明该文提出的方法相比于先检测后跟踪算法,有4～6 dB的检测性能增益;相比于常规单传感器多帧检测前跟踪算法,航迹跟踪精度有50%左右的提升。      

集中式BLUE滤波器在组网雷达中的应用

为解决组网雷达对目标跟踪中的量测非线性问题,提出基于最佳线性无偏估计器(BLUE)准则的融合滤波方法。建立以融合中心为原点的组网雷达对目标定位的量测方程,推导出极坐标系与球坐标系下跟踪目标的BLUE滤波模型。理论分析表明,集中式BLUE滤波架构在估计单个雷达量测转换误差统计特性的同时,还估计出雷达间量测转换误差的统计特性。因此,跟踪精度和置信度较分布式BLUE滤波方法有显著提高,计算量较其他算法也有明显优势。不同场景下的仿真分析证明:该方法在不同状态噪声水平下的表现优异,是一种很有竞争力的跟踪算法。     

一种适用于非高斯杂波背景的DP-TBD算法

针对动态规划检测前跟踪(DP-TBD)算法在非高斯杂波背景、起伏目标条件下检测和跟踪性能差的问题,将粒子滤波引入动态规划的似然比阶段指标函数计算中,利用粒子权值的均值表征目标存在假设下的似然函数,导出似然比指标函数模型,进而给出了一种适用于非高斯杂波背景和起伏目标的最大似然DP-TBD算法。应用文中算法在对数-正态杂波、Swerling起伏模型条件下,对目标的检测跟踪性能进行了仿真,并与两种传统的DP-TBD算法进行比较,验证了该算法的有效性。     

多传感器数据关联与状态跟踪算法分析

本文针对给定区域内目标运动状态跟踪检测环节,多传感器跟踪系统获取测量数据与实际状态间存在较大偏差的问题,拟提出一种建立多目标数据关联、支持多传感器航迹融合的目标运动状态跟踪算法。将全局最近邻算法与改进后的全局最近邻算法进行组合,构建给定空间内不同目标间相对距离测量算法,建立目标测量结果与预测值间的相似度矩阵,保证数据关联结果的准确度;基于粒子滤波算法在利用单传感器检测目标时因干扰因素出现的偏差,引入FOA算法实现对融合系数的优化,获得目标状态的精准估计结果;在此基础上,利用粒子滤波优化算法建立分布式结构下多种电化学传感器的航迹融合算法,经均质化处理实现多个传感器航迹的融合与加权处理,最终仿真实验结果显示该算法可有效提升对融合航迹下目标的跟踪精度,为多传感器跟踪系统的开发设计提供重要参考。     

异步多基地雷达分布式批估计方法研究

在实际应用中,由于初始偏差、采样速率不同等原因,系统量测一般也非同步。多基地雷达数据通常面临异步数据融合问题。为了解决该问题,该文按照批处理的思路,联合一段时间内的多个异步数据对同一目标状态进行估计,并基于最优贝叶斯估计原理,提出了一种新的批估计数据融合准则;然后,依据该准则推导出了一种解析的分布式批估计方法;最后,针对非线性非高斯场景,提出了一套完备的粒子滤波实现方案。仿真结果表明,文中提出的方法相比现有方法具有跟踪精度高,计算量小等优点。     

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.     

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.     

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.     

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.     

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.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.