基于GPS的星地激光通信捕获对准研究

提出了基于GPS坐标解算实现星地激光通信捕获、跟踪和对准(ATP)初始捕获的方法。星地激光通信信标光跟踪系统通过对地面GPS坐标和卫星坐标的解算,得到地面光学天线的方位角和俯仰角,光学天线根据角度旋转对准信标光,从而将信标光引入粗跟踪CCD的视场。给出了GPS坐标解算算法和信标光方向角度随卫星坐标变化的仿真曲线。用二维电机进行了地面转台的捕获实验,对实验数据进行了捕获精度的分析,结果表明,通过GPS坐标解算能够快速地实现信标光的初始捕获。     

无线光通信GPS辅助定点捕获实验研究

针对无线光通信对快速、精准的光束对准技术需求,为减小系统链路建立时间,增加捕获可靠性,提出将GPS技术应用于光通信实验系统中。以TMS320F2312为控制核心,可根据实时GPS坐标解算出需调整的方位及俯仰角,进而驱动二维转台完成初始捕获,据此进行了多次初始捕获实验。结果表明,采用GPS导航定位技术,可快速实现信标光的初始捕获,且具有较高的捕获成功概率。     

空间光通信系统的初始捕获对准研究及实验

文章提出采用GPS(全球定位系统)坐标解算和蜂窝螺旋扫描来实现空间光通信ATP(捕获、跟踪和对准)系统初始捕获的方法。首先由通信两端的GPS坐标计算出光学天线的方位角和俯仰角,光学天线根据计算的角度值大致对准信标光的方向,从而缩小了信标光捕获的不确定区域。然后在不确定区域内执行蜂窝螺旋扫描,从而将信标光引入粗跟踪CCD(电荷耦合元件)的视场内,实现初始捕获。通过地面捕获实验验证了上述方法的有效性。     

市内建筑间无线光通信GPS辅助单向捕获研究

为减小无线光通信链路建立时间及增加系统捕获可靠性,提出将GPS技术应用于光通信实验系统中。以TMS320F2812为控制核心,搭建了无线光通信定点单向捕获实验系统。系统采用用户界面统一控制,双方GPS坐标手工输入至用户界面,解算出需调整的方位及俯仰角后送于F2812,驱动二维转台完成初始捕获,据此选择多点进行了多次单向初始捕获实验。结果表明,采用GPS导航定位技术,可快速实现信标光的初始捕获,且具有较高的捕获成功概率。     

定点激光通信系统天线捕获技术

对系统的硬件组成和算法原理进行了论证.在距离为12.5km两个点上使用双天线GPS系统提供的位置信息结合坐标转换矩阵,解算通信双方互指的方位角和俯仰角,控制伺服转台完成了视轴天线捕获实验.借助于电子经纬仪系统完成了对捕获不确定区域大小的论证,确定地面定点激光通信系统捕获不确定区域大小为25mard.     

动态空间激光通信系统视轴初始指向建模及验证

捕获、对准、跟踪系统是空间激光通信重要组成部分,是通信正常进行的前提与保障。针对捕获系统中的初始指向内容进行了详细研究,给出初始系统指向系统模型,应用坐标转换矩阵补偿由于位置不同、姿态变化、安装基准轴差异、初始零位不一致等对初始指向方位角和俯仰角的影响。提出初始指向系统视轴标校方法,根据误差分析方法确定了指向精度及捕获不确定区域大小。在飞机-飞机动态演示实验中,应用双天线全球定位系统/捷联导航系统(GPS/INS)组合器件实时得到位置、姿态等参数,实现初始指向系统性能测试。借助观靶相机实际测量本系统捕获不确定区域大小为10mrad,与理论分析结果基本一致。     

GPS/INS技术在静态激光通信初始捕获中的应用

为了实现水平远距离大气无线激光通信链路快速建立,并快速获得捕获不确定区域的大小,采用了GPS/INS组合导航系统来完成静态水平链路无线激光通信初始捕获的对准定位,同时对该系统的对准算法进行了研究并优化。首先,分析了GPS/INS工作原理,根据捕获过程,提出针对该过程的捕获模型,并且分析了该模型的可行性。接着,针对该模型提出相应的静态初始对准算法。然后,通过该算法进行了外场实验。最后,根据实验结果校正捕获模型与其算法,经实验获得了捕获不确定区域的大小为27 mrad。基本满足10 km水平链路大气无线激光通信初始捕获的基本要求,其特点为捕获速度较快,其捕获速度优于10 s,基本不受天气影响。     

弹载组合导航算法仿真实现

本文阐述了基于高旋类弹载组合导航系统的功能和精度仿真,该仿真系统利用实弹惯性测量单元数据及卫星导航数据进行算法融合,从而实现空中动态初始对准及姿态位置解算功能.本算法中主要应用了EKF(扩展卡尔曼滤波)技术融合GPS数据和IMU(惯性测量单元)完成初始对准和航姿解算功能,经过算法仿真论证,本算法可以实现弹载体的航姿和位...     

基于软件的GPS信号捕获跟踪算法研究

对GPS软件接收机的捕获和跟踪部分进行了研究。对于捕获模块,通过对常用串行搜索捕获算法和并行频域搜索捕获算法的比较和分析,提出了一种新型并行码相位搜索捕获算法;对于跟踪模块,提出采用非相干延迟锁相环对码进行跟踪,同时采用Costas环对载波进行跟踪;最后,从捕获和跟踪的GPS信号中提取出导航电文,并根据电文中的参数计算出了用户的位置坐标,并在Matlab中对用户的位置坐标进行了定位解算验证。     

基于四象限探测器的监视对准实验

激光束的空间稳定性是激光系统非常重要的指标,要保持激光束的空间稳定性就必须先对激光束的指向进行监测.本文采用四象限设备作为532 nm半导体激光指向的监测设备,它可以快速响应光斑的中心位置.实验测量了激光束自身的漂移抖动量,然后利用转台和透镜组合标定了3个角度的指向误差.实验结 果表明,激光束的漂移抖动最大值为3...     

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