组网雷达检测概率研究

分析了单部雷达对非起伏目标和起伏目标（Swerling Ⅰ～V）的检测概率与检测因子的关系,对多部雷达的检测概率进行融合,研究并比较了组网雷达与单部雷达的检测概率及检测范围.对基于单脉冲雷达和多脉冲积累雷达的检测概率仿真分析表明,在一定的虚警概率下,组网雷达提高了对目标的检测概率,相同的发现概率下的组网探测距离大于单部雷达探测距离.     

雷达组网反隐身可行性仿真分析

通过仿真算法分析出同一目标在不同空间角度的雷达截面（RCS）值以及不同频段探测时的不同RCS值,并通过仿真计算提出雷达组网反隐身的可行性。     

雷达目标特征数据库在雷达组网仿真上的应用

传统雷达组网仿真中,认为目标为点目标,目标的RCS(Radar Cross Section)是一个常数;实际上目标的RCS是随雷达频率、目标相对雷达姿态变化的函数。该文通过对复杂雷达目标进行电磁建模,计算其在各姿态和各频点的RCS数据,把计算结果存储在数据库中建立雷达目标特征数据库。建立了雷达组网仿真系统,系统由主控计算机、雷达目标特征数据库、若干雷达站组成。仿真结果表明:利用雷达目标特征数据库获得雷达在每个时刻观察的RCS比传统的把飞行器RCS当成常数,进行雷达组网仿真,仿真结果更接近实际的情况;通过多个雷达组成雷达网进行数据融合共同探测目标,可以大大提高雷达对目标的检测概率。     

微波超视距雷达组网探测范围研究

本文研究了雷达组网时目标雷达散射截面（radar cross section, RCS）在方位角上的分布对微波超视距雷达探测范围的影响. 首先在蒸发波导条件下,利用抛物方程法推导了电磁波的传播因子,得到了电磁波场强随传播距离和高度的变化规律;然后在此基础上,结合目标RCS在高度和方位角上的分布,研究了目标的回波功率,利用改进的雷达方程得到了微波超视距雷达对目标最大探测距离的计算方法,建立了雷达网探测范围评估模型并进行了仿真. 仿真计算结果表明:在目标运动姿态未知情况下,雷达组网使雷达的探测范围增加了11.20%,在特定方向上使探测距离增加了16.67%;在目标运动姿态已知情况下,雷达组网在部分方位角上增大了最大探测距离,为微波超视距雷达的组网使用提供了理论支撑.     

雷达组网探测巡航导弹能力建模与仿真

建立雷达组网探测巡航导弹能力的评估模型是雷达组网作战效能评估的一个重要内容。本文在模拟巡航导弹飞行航迹的基础上,通过网内雷达与目标间的坐标转换,推导了网内各雷达对巡航导弹雷达散射截面积（RCS）观测值随着时间变化的起伏模型,再依据雷达组网点迹融合探测性能模型,仿真分析了雷达组网对巡航导弹的探测能力。结果表明该方法能够比较准确地计算雷达组网对巡航导弹的发现概率,为雷达组网系统的作战效能评估提供了一定的依据。     

反隐身飞机突防战术仿真

为研究体系作战条件下地基雷达组网和预警机结合探测隐身飞机能力,基于隐身飞机三维建模并计算雷达散射截面积(Radar Cross Section, RCS),分析了隐身飞机突防过程中不同时刻雷达探测性能变化情况。首先,采用专业软件建立了某型隐身飞机三角面元模型,采用物理光学法(Physical Optics, PO)计算了飞机RCS。其次,建立了雷达坐标系与飞机机身坐标系转换关系,计算了不同时刻机身坐标系中雷达照射角度。最后,通过构建隐身飞机突防模型,研究不同时刻地基雷达组网和预警机联合探测隐身飞机的雷达探测距离和探测概率变化情况。仿真结果表明,地基雷达组网和预警机能够有效利用隐身飞机侧向、后方和上方RCS较大(10～20 dB)的特点,其中,预警机最大探测距离达151 km,平均探测距离在80 km左右,地基雷达组网的平均距离探测为50 km左右,对隐身飞机具有良好探测能力。     

一种机载组网雷达协同目标检测算法

多机协同的机载雷达组网联合目标探测可有效提高复杂电磁干扰环境下对隐身弱目标的探测能力。文中针对机载雷达组网探测时空间配准误差大、协同探测难以实现的难题,提出了一种基于轨迹空间配准的协同目标检测算法,通过雷达间少量距离-多普勒域数据及低检测门限下目标轨迹域数据的交互,采用极大似然估计广义似然比检测器对目标进行联合恒虚警检测(CFAR),并通过轨迹域空间配准与CFAR的迭代计算,实现配准精度和目标联合检测性能的双提升。数值仿真实验的结果表明,在四部雷达组网工作时,在相参积累后信噪比9 dB、虚警概率10^-4的典型场景下,经过迭代处理,空间配准精度可达到一个距离-多普勒分辨单元;对目标的检测概率由单部雷达的28.5%提高到四部雷达协同下的83.67%。     

一种组网雷达波束资源优化分配模型

针对空面目标组网雷达协同调度的资源优化分配问题,通过分析不同目标的重要性、RCS和跟踪质量对调度资源的差异化需求,以组网系统探测效益为优化目标,构造了一种基于波位调度的动态规划模型。利用改进的拍卖算法对该模型求解各雷达最优的波位分配,在满足不同类型目标对跟踪资源需求的同时,降低了组网系统总体波束资源的消耗。该方法解决了多雷达目标调度中资源分配和冲突消解的协同问题,降低了计算量,提高了时间和能量两种资源的合理分配和有效利用率,实现了组网系统高效的波束资源管理。通过仿真验证,证明了所提模型的正确性和算法的有效性。     

雷达组网协同探测试验航次数量设计改进

雷达组网协同探测试验是在实际的外场环境下,利用实装飞机作为目标,测试两部同型雷达对目标协同探测的稳定跟踪距离。通过对传统航次数计算方法进行分析,发现其将距离取样间隔内检测概率的变化视为线性变化,当距离取样间隔增加时,数据评估的检测概率与实际雷达检测概率间出现明显误差,使得统计结果的可靠性下降,提出一种试验航次数量改进算法,该方法能够实时计算检测概率误差并进行修正,选择最佳距离取样间隔,在确保样本量的前提下获得合理的航次数量,节约了试验成本。     

基于仿真计算的飞行器雷达隐身性能评估

从飞行器雷达散射截面的计算机仿真出发,对运动飞行器的RCS动态特性和复杂电磁环境下的隐身性能进行研究.基于运动目标姿态参数的转换原理,得到运动目标的动态RCS特性,通过相对计算方法计算雷达的瞬时探测概率,并给出有源和无源干扰条件下探测概率的计算方法;以单部雷达的目标检测准则为基础,给出了雷达组网模式下的综合检测准则;考...     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks