压制干扰下基于联邦滤波的机动目标跟踪方法

针对远距离压制干扰下机动目标跟踪问题,分析了远距离大功率压制干扰对于雷达探测及测量精度的影响,引入新的量测模型模拟雷达在压制干扰下由于探测概率下降出现的目标暂消现象,并利用去相关无偏量测转换方法将球坐标下的量测转换到直角坐标系下.在此基础上,基于自适应联邦滤波的思想建立了雷达压制干扰下的机动目标跟踪算法.仿真结果表明,...     

一种改进的机载多普勒雷达目标跟踪算法

针对传统的基于多普勒雷达量测转换的目标跟踪算法只适用于静止雷达的问题,将该算法推广至机载多普勒雷达。在每个递推周期里,首先将机载导航数据转换到东北天坐标系中;然后,将距离量测转换成东北天系下的位置伪量测,由此完成对目标的位置滤波;最后,联合目标位置滤波值及多普勒量测对目标进行运动状态滤波,由此得到目标的位置最终估计值。仿真实验结果表明,改进后算法的跟踪精度优于传统的多普勒雷达目标跟踪算法。     

一种高数据率雷达跟踪慢速目标的数据互联算法

杂波环境下, 现有的最近邻数据互联算法在高采样率雷达跟踪慢速目标时, 由于量测误差远远大于目标实际运动的距离, 量测值往往难以落入预测波门之内, 从而造成数据互联失败。针对这一问题, 提出了一种自适应距离最近邻数据互联算法。该算法用状态估计向量中的位置信息计算与下一时刻量测值的实际距离来代替预测中心与量测值的统计距离, 降低了预测中心不确定性造成的漏互联概率, 从而提高了跟踪精度。实际距离波门的大小与雷达和目标距离、雷达测距精度、雷达测角精度有关, 并且随着时间实时变化。通过在地心坐标系下的跟踪滤波仿真证明, 该算法能够有效地实现高数据率雷达对慢速目标的跟踪, 且跟踪精度较高, 具有一定的工程实用价值。     

变维的机动目标跟踪算法

为改善现有机动目标跟踪方法存在的跟踪精度不高、滤波易发散的问题,提出了一种RA-Jerk-EKF算法,该算法将目标径向加速度信息引入量测向量,通过增加雷达量测向量维数提高机动目标的跟踪精度。在信号处理阶段利用分数阶傅里叶变换(FRFT)估计出目标的径向加速度,并将其通过坐标转换引入量测向量中;在数据处理阶段采用Jerk模型和扩展卡尔曼滤波(EKF)算法解决滤波算法中非线性量测方程问题;最后将该方法与传统的不带径向加速度的Jerk-EKF方法进行了仿真比较。结果表明,该方法在跟踪精度,位置、加速度和速度估计精度方面均有所改善。     

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。     

LFM雷达对临近空间高超声速目标的跟踪研究

针对临近空间高超声速目标跟踪的问题,提出了一种ECEF坐标系下基于径向速度补偿和相邻时刻目标量测对消处理的高超声速目标跟踪算法.首先,充分分析了目标高超声速运动对雷达探测跟踪的影响,并在此基础上合理构建了目标高超声速运动下的量测模型,以避免模型失配所引起的滤波发散问题;其次,利用解模糊处理后的径向速度估计对目标高超声速运动引起的高动态偏差做近似补偿,以将问题转换为低系统偏差下的状态估计问题,最后,通过基于相邻时刻目标量测对消处理的单雷达量测方程构建,可有效回避低系统偏差存在下的航迹关联问题,进而实现临近空间高超声速目标的可靠跟踪.仿真结果表明,与现有的临近空间目标跟踪算法相比,该算法具有较高的定位跟踪精度.     

一种高精度机载GMTI雷达数据滤波方法

针对机载GMTI雷达地面机动慢速多目标跟踪难题,提出了一种新颖的高精度机载GMTI雷达数据滤波跟踪方法。针对机载GMTI相控阵雷达的特点,引入一种新的机载GMTI雷达量测模型,采用Doppler伪量测形式减弱Doppler量测与目标状态之间的强非线性关系,并进行了量测误差转换;通过论述发现,采用运算速度较快的UKF滤波器进行非线性滤波估计,可以有效地降低由机体坐标系到地面站惯性坐标系的复杂变换引起的估计误差放大。实验证明,该方法可以有效地提高地面机动多目标的跟踪精度,满足实际雷达跟踪系统要求。     

视线坐标系带多普勒观测的雷达目标跟踪

雷达观测量与目标状态呈非线性关系,使目标跟踪成为非线性滤波问题,目标状态估计精度与跟踪滤波算法复杂度成了一对不可调和的矛盾。提出了在视线坐标系中建立观测方程,将笛卡尔坐标系中的目标运动方程转换到视线坐标系中,使得雷达观测量尤其是多普勒速度观测与目标状态呈线性关系,并推导得到了该坐标系下的卡尔曼滤波算法,比较了与标准卡尔曼滤波算法的不同。仿真结果表明,该算法不仅能改善跟踪滤波效果,还明显降低了算法复杂度,节省了运算时间。     

基于去相关无偏量测转换的机动目标跟踪

针对雷达非线性量测信息下的机动目标跟踪问题,提出了一种基于去相关无偏量测转换的跟踪算法。该算法以交互多模型算法为基础,利用多个并行的滤波模型覆盖目标可能的运动模式,其中各个子滤波器均采用去相关无偏量测转换方法解决系统量测与目标运动状态之间的非线性问题。该量测转换方法同时也克服了量测转换固有的缺陷。蒙特卡罗仿真结果表明,相对于传统的量测处理算法,采用基于去相关无偏量测转换的跟踪算法能获得更高的目标跟踪精度。     

雷达机动目标跟踪的卡尔曼粒子滤波算法

为解决不敏粒子滤波算法对雷达机动目标跟踪实时性差和跟踪起始阶段收敛慢的问题,引入卡尔曼粒子滤波算法。通过坐标转换将实际的极坐标雷达观测数据转换为直角坐标数据,然后用线性最优的卡尔曼滤波器估计粒子状态先验概率密度,最后用非线性最优的粒子滤波器精确估计目标状态后验概率。仿真实验表明,与不敏粒子滤波相比,卡尔曼粒子滤波以牺牲较少精度(减少约6%)的代价,实现机动目标跟踪的实时性(约为前者的1/5),起始阶段收敛性更好。     

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.     

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 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.     

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.     

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