基于NSGA的车载天线布局优化

分析了天线间相互干扰的参考量---耦合度的计算方法,以达到耦合度最小为目标,采用非支配排序遗传算法(NSGA)对车顶天线布局的电磁兼容性能进行优化设计,编程实现了车顶天线布局优化。     

天线布局优化仿真研究

随着车载无线系统上装无线设备电磁环境日益复杂,设备间电磁干扰日益严重,采用仿真技术进行天线布局优化可以有效减小设备间干扰。本文分析了影响车载天线系统天线布局的主要因素,得出天线优化布局的优化目标为天线间的耦合度和方向图失真度,建立了天线布局优化模型,采用改进的遗传算法对车顶天线布局进行优化设计,在电磁兼容设计初期得出粗略的最佳布局方案,使其满足电磁兼容性能要求,降低了天线布局设计的难度,并设计了电磁兼容优化仿真软件,实现了车载系统的优化布局仿真,达到工程实际要求。     

车载通信系统电磁兼容仿真研究

随着通信电子的发展,电磁兼容性已成为车载通信系统集成的重要指标,直接影响着整个系统的性能指标。本文结合电磁兼容对车载通信系统的性能影响,分析了车载通信系统的电磁兼容影响因素,建立了系统集成电磁兼容指标分配模型,并针对车顶天线布局、车内系统互连进行了仿真分析,为车载通信系统集成指标量化提供了一种方法和思路。     

车载短波螺旋天线仿真与实验

通过ＨＰＳＳ仿真软件设计车载短波螺旋天线,计算出该天线的电参数和辐射方向图,将所设计的天线模型架设在卡车车顶,进行远距离通信实验,实验表明圆极化的螺旋天线接收水平极化所辐射的信号,话音质量良好。     

电子干扰飞机天线布局研究

电子干扰机任务系统具有发射功率大、干扰频带宽的特点,任务系统天线与飞机平台天线间电磁兼容设计是全机设计的重点,从电子干扰机飞机平台天线布局、任务系统天线布局、全机天线布局三个方面进行分析并分别给出天线布局的一般原则,最后,以波音737型客机为例,给出将其改装为电子干扰飞机后天线布局图,并结合美军EC-130E通信干扰机,对其天线布局进行了分析,为电子干扰飞机天线布局设计提供参考。     

利用矩量法设计车载多天线系统天线布局

利用矩量法仿真天线间的耦合度,对车载多天线系统的天线布局进行了预测,根据预测结果设计了多天线系统的布局,并利用试验对实体模型进行测试,验证所得天线间耦合度测试数据与仿真数据,结果证明了仿真数据的可靠性和布局预测的正确性。     

舰载多天线互耦分析与优化布局

提出了基于天线互耦矩阵的特征值分解的天线优化布局方法,并利用电磁软件FEKO的计算结果算出了一个舰载天线优化布局实例。     

高速公路ETC车道单双天线布局的分析与比较

为了分析在ETC专用车道建设中双天线布局的必要性,采用单天线与双天线布局相比较的方法,通过对陕西省路网环境及170多万条交易数据分析,并计算交易耗时和行车安全约束的车辆通行限速,认为双天线布局并不会提高车辆的通过速度,交易成功率也不优于单天线布局。陕西省百余条ETC专用车道均采用单天线布局。实践证明,单天线布局能够大幅节约ETC车道的建设和维护成本,降低系统故障率和逻辑处理复杂度,能够满足ETC建设要求,很好地为公众服务。     

民用飞机甚高频天线布局的方向图仿真

飞机在起飞、飞行、着陆阶段需要与飞机和地面基站之间通过甚高频天线进行可靠的语音和数据通信。一般在干线飞机上,会安装两到三副甚高频天线,机身上能够进行天线布局的位置有限,甚高频天线方向图容易受到机身外形影响,因此进行天线布局时需要重点考虑甚高频天线的位置。本文介绍了甚高频天线布局时需要考虑的问题,并选取机身上5个典型位置,对甚高频通信天线在机身上不同安装位置上的方向图进行仿真分析,为甚高频天线布局提供一定的参考。     

深亚微米SOI工艺SoC设计中天线效应的消除

深亚微米SOI片上系统芯片(SoC)因其工艺特性,按照常规的布局布线(PNR)流程,出现了约一万个天线效应违规。介绍了一种在布局布线阶段不插入反偏二极管就可以消除大量天线效应违规的优化迭代流程。通过对天线效应的产生以及天线比率公式的分析,从线长和栅面积角度考虑天线效应的修复,结合自动布局布线设计工具SoC Encounter对这些因素的控制,可以在布局布线阶段消除天线效应的违规,并能与版图验证的结果保持一致。在一款通用抗辐照SoC芯片的设计中,应用该优化流程在布局布线阶段消除了设计中的天线效应违规,有效节约了芯片整体设计时间。     

折反光学系统最佳红外像面位置的研究

较深入地研究了折反光学系统的红外像面,为确定实际的红外像面提出了一个新方法—计算从可见光边缘无色的弥散圆到红外最佳像面的距离。实践证明,这是确定这类光学系统最佳像面的一个方便、可靠的方法。     

A novel overlay process for imprint lithography using load release and alignment error pre-compensation method

As a low-cost and high-efficiency alternative to conventional photolithography, imprint lithography has been paid serious attention for it can realize the pattern transfer easily and repeatedly. Even so, there is still a long way to go before this technique can be used to manufacture ICs since the layer-to-layer alignment is a main obstacle. In this paper, the pattern distortion and position shift induced by loading force and friction force are investigated and an optimized process is proposed to realize high precision overlay, in which an optimal loading force and a load release and an alignment error pre-compensation (LRAEPC) method are adopted. The optimal loading force is acquired by comparing the variety trends of the residual layer and position shift with the loading force. Using the optimal loading force, transferred patterns with proper resist thickness and the minimal distortion are achieved. In LRAEPC method, load release is used to correct the pattern distortion and to alleviate the position shift. To avoid subsequent position adjustment in the fluid after load release, the pre-compensation alignment is performed before the mold is in contact with the wafer. This process does not locate correct alignment position and there is an alignment compensation value determined by the statistical data of alignment position shift after load release. Using this pre-compensation alignment method, the correct alignment can be obtained after load release.     

相控阵雷达天线最佳波位研究

围绕多功能相控阵雷达扫描波位的优化设计,详细研究了相控阵天线的最佳波位问题,给出了最佳波位序列的迭代算法.考虑到实际相控阵天线波束跃度的限制,提出了波位序列最佳性的度量方法,对数字移相式的相控阵天线波位序列进行了分析和评估.     

A Joint TDOA/FDOA Lo calization Algorithm Using Bi-iterative Method with Optimal Step Length

In order to improve the estimation accuracy of multi-station joint Time difference of arrive/ Frequency difference of arrive (TDOA/FDOA) location with Bi-Iterative method, a solution for the position of target with Gauss-Newton optimal step length is proposed in this paper. First, get the initial estimation of target based on Two-stage weighted least-squares (TSWLS) algorithm, and then alternately solve the position and velocity of the target with Bi-Iterative method. In this paper, Gauss-Newton method is applied to iteratively solve the target position, including the detailed equations of the descending direction and the optimal iterative step length in each iterative process. Simulations are carried out to examine the algorithm's performance by comparing it with TSWLS method and Gauss-Newton method regardless of the step length. The results show that when Gauss noise variance is small, the estimation accuracy is close to Cramer Rao lower bound (CRLB) and the proposed method performs better than the other two methods. In addition, because the model which includes the position and velocity of the observation station and the target is in line with the over-the-horizon reality scene in this paper, our research has certain practical value.     

Optimal edge-preserving hybrid filters

Based on the least mean square error criterion at the edge position, a new algorithm is presented to obtain a class of optimal edge-preserving hybrid filters that include the Lee (1980) additive filter and the gradient inverse weighted filter. As a result, we show that the gain of the Lee additive filter is not optimal and derive the optimal form of this filter. In addition, some examples are given.     

高速高精度定位机构的优化设计

提出了一种新型2-自由度(2-DOF)高速高精度平面并联定位机构。首先考虑机构的运动学性能,基于雅可比条件数进行了机构构型的优化设计,并以全局性能指数为目标,得到了机构的最佳工作空间位置及形状;然后提出一种用于高速度和高精度机构的优化目标函数,进行了机构的结构尺寸参数优化。仿真结果显示,优化设计后的机构可实现高速高精度,具有较好的运动学性能。这种优化设计方法对此类结构的设计具有指导意义。     

基于混合变量规划的雷达最优搜索方法

针对预警机所提供引导信息下相控阵雷达进行快速搜索,以3倍均方差法为依据来划分初始搜索空域并对其进行波位编排,根据先验信息得到目标在各个波位的出现概率.考虑到雷达对各个波位的照射顺序,以最小化目标平均发现时间为目的,建立基于混合变量规划的相控阵雷达搜索资源最优分配模型.使用拉格朗日乘子法对模型进行求解,可同时得到最优搜索...     

The optimal control of a constrained drive system with brushless DCmotor

The optimal (according to the quadratic performance index) control method of a drive position system with an electronically commutated brushless DC motor is discussed. Initially developed for linear, unconstrained, and undistributed systems, this optimal control method is now applied to a system having constrained state and input variables (e.g. armature voltage, armature current, rotor speed) and unknown disturbances (e.g. load torque). The method uses an undisturbed and unconstrained model for a model-following adaptive control of the real system. The control method is verified through computer simulation using the data from a real drive position system. Results show that the controlled system operates effectively at the limiting state variables, which represent the real system. In addition, the final position is reached without overshoots     

A control algorithm for autonomous optimization of extracellular recordings

This paper develops a control algorithm that can autonomously position an electrode so as to find and then maintain an optimal extracellular recording position. The algorithm was developed and tested in a two-neuron computational model representative of the cells found in cerebral cortex. The algorithm is based on a stochastic optimization of a suitably defined signal quality metric and is shown capable of finding the optimal recording position along representative sampling directions, as well as maintaining the optimal signal quality in the face of modeled tissue movements. The application of the algorithm to acute neurophysiological recording experiments and its potential implications to chronic recording electrode arrays are discussed.     

Surface-marker cluster design criteria for 3-D bone movementreconstruction

When three-dimensional (3-D) human or animal movement is recorded using a photogrammetric system, bone-embedded frame positions and orientations are estimated from reconstructed surface marker trajectories using either nonoptimal or optimal algorithms. The effectiveness of these mathematical procedures in accommodating for both photogrammetric errors and skin movement artifacts depends on the number of markers associated with a given bone as well as on the size and shape characteristics of the relevant cluster. One objective of this paper deals with the identification of marker cluster design criteria aimed at the minimization of error propagation from marker coordinates to bone-embedded frame position and orientation. Findings allow for the quantitative estimation of these errors for any given cluster configuration and suggest the following main design criteria. A cluster made up of four markers represents a good practical compromise. Planar clusters are acceptable, provided in quasi-isotropic distribution. The root mean square distance of the markers from their centroid should be greater than ten times the standard deviation of the marker position error. The second objective of this paper deals with the identification of the optimal cluster position and orientation on the limb aimed at the minimization of error propagation to anatomical landmark laboratory coordinates. Cluster position should be selected to minimize skin movement artifacts. The longest principal axis of the marker distribution should be oriented toward the relevant anatomical landmark position