基于Auto CAD建模的目标RCS计算技术

本文描述了基于Ａｕｔｏ ＣＡＤ建模的目标ＲＣＳ计算技术，给出了由Ａｕｔｏ ＣＡＤｒ ＤＸＦ文件自动提取目标信息的方法，提供了一种在微机上计算复杂目标ＲＣＳ的实用方法。     

微带天线RCS缩减技术及分析方法

分析了微带天线ＲＣＳ（雷达散射截面）缩减的物理机制，对典型的ＲＣＳ缩减技术进行了综述，评论了几种计算微带天线ＲＣＳ的理论方法，指出了微带天线ＲＣＳ研究中值得探索的若干问题。     

MIPS公司两款64位RISC微处理器技术与性能

美国ＳＧＩ电子计算机公司是制造高性能可视化计算系统的厂商，其产品的“芯”脏是由子公司ＭＩＰＳ技术公司设计的。近日，从ＭＩＰＳ公司总部赶来的Ｊａｍｅｓ和Ｓｔｅｖｅ先生在北京介绍了该公司的最新两款微处理器──Ｒ１００００和Ｒ５０００的结构与性能。１９９６年伊始，ＭＩＰＳ技术公司在美国加州山景城宣布，它的２７５ＭＨｚ６４位ＲＩＳＣ微处理器Ｒ１００００，将在今年下半年上市，其ＳＰＥＣｉｎｔ９５值为１２，ＳＰＥＣｆｐ９５值为２４，在业界处于领先地位。此外，由ＮＥＣ及东芝公司生产的２００ＭＨｚＲ１００００微…     

图形电磁计算法分析高频区复杂目标虚拟双站散射特性

通过应用单－双站等效原理，将目前分析高频区复杂目标后向ＲＣＳ最有效方法之一的图形电磁计算（ＧＲＥＣＯ）技术拓广到计算双站ＲＣＳ领域，并给出了与实验结果符合良好的标准体与复杂目标的虚拟现实实例的单双站ＲＣＳ计算曲线，具有很好的工程应用价值。     

迭代物理光学方法（IPO）求解高频部件相互耦合问题

在复杂目标的ＲＣＳ计算中，各个部件之间的耦合是一个必须考虑的问题。本文采用我学（ＰＯ）方法，通过多次迭代，逐步修正各散射体上的面电流，然后采用Ｓｔｒａｔｔｏｎ－Ｃｈｕ积分得到ＲＣＳ。本文应用ＩＰＯ方法计算了相垂直的两个导体板的散射近场和ＲＣＳ《计算配用ＦＤＴＤ方法得到的结果有很好的一致性。ＩＰＯ方法可望用于改进基于ＰＯ方法的高频近似方法，如面元法的计算精度。     

新型箔片云团双站电磁散射计算方法研究

提出了计算圆形、四边形金属箔片云团单箔片双站ＲＣＳ的方法，给出了极化变换和散射矩阵计算的具体公式，可用于大数量高密度箔片云团双站ＲＣＳ计算研究，并给出了数值结果。     

AUTOCAD在有线电视网络设计中的应用

针对目前有线电视信号传输网络手工绘图的诸多问题对网络图的一般处理方法，建立了自动绘图和自动处理数据的数学模型，详述了利用ＡＵＴＯＣＡＤ ＦＯＲ ＷＩＮＤＯＷＳ Ｒ１２对有线电视系统网络图进行计算机辅助设计的思想和实现技术。     

荆州市邮电局“九七工程”系统平台方案设计（一）

以荆州市邮电局的系统建设为例，分服务器、网络系统、数据库管理三部分提出了荆州市邮电局市话业务计算机综合管理系统的系统平台技术方案。该系统采用Ｃｌｉｅｎｔ／Ｓｅｒｖｅｒ计算模式，采用两台ＩＢＭ ＲＳ／６０００－Ｒ４０小型计算机共享ＲＡＩＤ－５磁盘阵列组成Ｃｌｕｓｔｅｒ，保证系统服务的高性能及稳定可靠，在网络系统的设计上，该系统选用ＩＢＭ８２６０及ＩＢＭ８２７３构建ＡＴＭ核心网络。在对接入核心网络的域     

一种改进的SAR自动聚焦算法

自动聚焦是高分辨率合成孔径雷达（ＳＡＲ）中的一项重要技术。如果进行实时成象，就要求自动聚焦算法有很高的计算效率。移位相关法（Ｓｈｉｆｔ－ａｎｄ－Ｃｏｒｒｅｌａｔｅ－ＳＡＣ）就是这种的一种算法。它最先是由Ｊｏｒｇｅｒ在１９９１年提出的，本文深入分析了这各算法，并对它进行了改进。     

快速计算电大尺寸目标双站电磁散射的方法

提出利用等效边缘电磁流方法快速计算复杂形体电大尺寸目标的双站ＲＣＳ。该方法运算速度快,考虑了边缘绕射和遮挡,计算精度高。在计算尖锥柱等典型散射体的ＲＣＳ的基础上,计算了一导弹模型在不同方位角下的双站ＲＣＳ,证实了本方法的可行性。     

High-frequency RCS of complex radar targets in real-time

This paper presents a new and original approach for computing the high-frequency radar cross section (RCS) of complex radar targets in real time with a 3-D graphics workstation. The aircraft is modeled with I-DEAS solid modeling software using a parametric surface approach. High-frequency RCS is obtained through physical optics (PO), method of equivalent currents (MEC), physical theory of diffraction (PTD), and impedance boundary condition (IBC). This method is based on a new and original implementation of high-frequency techniques which the authors have called graphical electromagnetic computing (GRECO). A graphical processing approach of an image of the target at the workstation screen is used to identify the surfaces of the target visible from the radar viewpoint and obtain the unit normal at each point. High-frequency approximations to RCS prediction are then easily computed from the knowledge of the unit normal at the illuminated surfaces of the target. The image of the target at the workstation screen (to be processed by GRECO) can be potentially obtained in real time from the I-DEAS geometric model using the 3-D graphics hardware accelerator of the workstation. Therefore, CPU time for RCS prediction is spent only on the electromagnetic part of the computation, while the more time-consuming geometric model manipulations are left to the graphics hardware. This hybrid graphic-electromagnetic computing (GRECO) results in real-time RCS prediction for complex radar targets     

NURBS曲面RCS的物理光学法混合计算

基于近似驻相法和直接积分法,在利用物理光学法(PO)计算NURBS曲面的雷达散射截面(RCS)的问题中提出一种混合积分法.这种方法既保持积分精度,又提高了计算速度.此外,归纳了七种不适合用一般驻相法处理的剖分面元.同时验证了计算中采用NURBS面元剖分对于提高目标RCS计算精度的作用.     

基于高频渐近方法的导弹目标群动态RCS 仿真

针对导弹目标群的动态RCS 仿真问题,该文提出一种基于高频渐近理论的高效预估方法。该方法基于最小能量弹道仿真得到弹头、诱饵和助推级等群目标的弹道,在测量雷达坐标系下解算得到各时刻目标的位置和姿态,建立分离过程的目标群动态场景,并利用物理光学法(PO)、等效边缘流法(EEC)和射线弹跳法(SBR)计算目标群的镜面反射、边缘绕射和多次反射贡献获得动态RCS 数据。与采用静态全极化数据的常规插值方法获取的RCS数据对比分析表明,在场景中各目标距离较远且无相互遮挡时,两者吻合;当目标群密集分布存在相互遮挡时,插值方法实现难度大大增加,而该文方法仍能快速得到有效的结果。      

GRECO: graphical electromagnetic computing for RCS prediction inreal time

An innovative approach to computing the high-frequency radar cross sections (RCSs) of complex radar targets in real time, using a 3-D graphics workstation, is presented. The target (typically, an aircraft) is modeled with the I-IDEAS solid-modeling software, using a parametric-surface approach. The high-frequency RCS is obtained through physical optics (PO), the method of equivalent currents (MEC), the physical theory of diffraction (PTD), and the impedance boundary condition (IBC) techniques. The CPU time for the RCS prediction is spent only on the electromagnetic part of the computation, while the more time-consuming geometric-model manipulations are left to the graphics hardware     

Soft-window averaging of Radar cross sections

Formulae are obtained for when the radar cross section (RCS) of a reflecting surface is smoothly averaged with respect to angle. Our results are derived using the physical optics approximation. The specific cases of near-broadside scattering from cylinders and flat plates are considered in detail. General results are derived for scattering from smooth surfaces in the high-frequency limit. It is shown that the high-frequency approximations to the smooth averages we employ are significantly more accurate than those previously obtained for hard-window averages. This should allow for more efficient and effective evaluations of dynamically collected RCS data. Analogous formulae for frequency averaging are also discussed.     

NURBS曲面建模的电大目标的宽带RCS快速计算

该文采用物理光学方法(PO),快速计算了非均匀有理B样条 (NURBS) 曲面建模的电大目标的时域瞬态散射和宽带雷达截面(RCS)。通过对频域物理光学散射场表达式进行逆傅里叶变换推导出卷积形式的瞬态散射表达式;对频域物理光学积分进行逆傅里叶变换得到时域物理光学积分的表达式。为了避免数值积分的使用,将NURBS曲面等参数离散为一组三角面片,运用Radon变换得到了时域和频域物理光学积分的精确闭式表达式。遮挡消隐时使用改进的z-buffer方法进行了加速。对时域瞬态散射场快速傅里叶变换得到目标的宽带RCS。文中计算了高斯脉冲平面波入射下模型的瞬态散射响应和宽带RCS,数值结果表明该文方法具有很高的计算精度,且计算速度快于传统时域物理光学法(TDPO)。     

基于海情和三次样条插值算法的舰船雷达散射截面优化分析方法

不同风浪等级下的海面会对船舰目标雷达散射截面(RCS)分析产生强烈影响。该文建立了一种船舰模型,利用物理光学法与矩量法的混合算法(PO-MOM)分析了不同海情下的船舰目标远场单站RCS。之后研究了海情对船舰目标RCS测试结果的影响。最后提出了基于3次样条插值(Cubic Spline Interpolation, CSI)算法的优化补偿方法。结果表明,随着海情等级的增加,舰船RCS降低;利用3次样条插值算法进行补偿,其补偿结果的平均值误差小于0.38 dBsm,最大值误差小于0.05 dBsm,因此能有效地减少海情对船舰RCS测试结果的影响。     

旋转对称物体的双站RCS估算

从物理光学（PO）积分方程入手，对旋转轴对称导体的双站雷达散射截面进行分析计算，并以旋转椭球为例，求出双站雷达散射截面计算式， 将该表达式退化到单站形式，计算结果与参考文献吻合较好，表明该方法的有效性。     

Electromagnetic Scattering Characteristics of PEC Targets in the Terahertz Regime

Electromagnetic (EM) scattering characteristics of perfectly electrical conducting (PEC) targets in the terahertz (THz) frequency range are investigated through the use of ray-based high-frequency EM techniques. These techniques include the methods of shooting and bouncing rays (SBR), and the truncated-wedge incremental-length diffraction coefficients (TW-ILDCs). The EM fields associated with each ray are tracked and computed, based on the principle of Physical Optics (PO) and/or Geometrical Optics (GO). The total field scattered from the PEC target is then obtained by summing up the EM contributions of each ray and each illuminated edge. In contrast to previously reported applications, these methods are combined together to solve three-dimensional (3D) scattering problems in the THz region. Due to the use of analytical formulas of Physical Optics and the truncated-wedge incremental-length diffraction coefficients method, the consideration of the multi-reflection effect in shooting and bouncing rays, and partially accounting for the second-order edge-diffraction effects in the truncated-wedge incremental-length diffraction coefficients method, we obtain an extremely efficient algorithm for studying THz scattering. It has excellent agreement with an accurate integral solver, the Multilevel Fast Multipole Algorithm (MLFMA), which cannot be used in handling large-scale THz problems. Both mono- and bistatic radar cross sections (RCS) of several PEC objects in the THz band are given to show the correctness and reliability of the asymptotic methods. The EM scattering characteristics of such targets in the THz region are analyzed. Great differences of the target characteristics between the THz and GHz regimes are observed and discussed.