基于降维稀疏重构的高效数据域STAP算法研究

本文基于信号稀疏重构技术,研究利用待检测样本直接进行动目标检测的高效空时自适应处理（STAP ）方案。该方案对时域降维的阵元-多普勒域数据采用空域稀疏重构技术估计高分辨率角度-多普勒谱,进而基于稀疏空时谱研究知识辅助的动目标检测算法。理论分析和仿真实验结果表明：本文算法能有效抑制杂波实现慢动目标检测,且运算量小易于实时并行处理。     

基于脉动阵的自适应波束形成算法仿真

为了满足自适应波束形成技术对实时性的要求,将脉动阵应用于波束形成算法中,以实现自适应权向量的实时获取.通过对QR分解采样矩阵求逆算法、混合型QR分解采样矩阵求逆算法和逆QR分解采样矩阵求逆算法的理论分析,利用脉动阵,对输入数据矩阵进行QR分解,得到旋转因子,实现自适应权向量的实时更新.针对三种算法各自的脉动阵进行仿真,结果表明,基于脉动阵的自适应波束形成算法实现了权向量的高速获取,并为后续的工程实践提供了理论依据.     

基于GSM基站信号的动目标探测方法

基于全球移动通信系统(GSM)蜂窝网信号的外辐射源系统,提出了一种利用GSM蜂窝网基站发射的信号实现对运动目标检测的外辐射源系统的方案。首先对GSM基站信号参数、信道特点、模糊函数进行了分析,然后给出了一个试验系统的组成及其处理方法,主要包括自适应直达波/杂波对消、相干检测及参数提取方法等,仿真分析了2种场景下的动目标检测及参数提取结果,验证了利用GSM信号进行目标探测体制的可行性。     

基于静电排斥力的大冲程MEMS变形镜

设计并制造了一种基于静电排斥力的大冲程MEMS变形镜,此变形镜采用了三个多晶硅结构层和一个金属反射层的设计.利用表面硅工艺完成了变形镜的加工,结合有限元分析软件和白光干涉仪对三种不同驱动器电极空间分布方式的静电排斥型变形镜进行了分析和研究.测试结果表明,静电排斥型变形镜在200V下能实现1.7 μm以上的位移,冲程较传...     

可自适应调节带宽的新型非线性二阶锁相环

大捕获带宽的同步给传统二阶锁相环带来了巨大挑战。文中针对传统锁相环捕获带宽与抑制噪声能力两者之间的矛盾,提出一种耦合非线性环节的新型二阶锁相环,利用非线性模块自适应调整环路噪声带宽。输入输出相位误差较大时利用较大的带宽迅速减小频偏;当相位误差由于环路控制作用而减小时,利用较小的带宽抑制噪声以提高跟踪精度。仿真结果表明,非线性二阶锁相环跟踪速度显著提高,且相比传统二阶锁相环,捕获带宽从4 kHz最大提高到18.8 kHz。     

System Throughput Analysis of Rate Adaptive TDMA System Supporting Two Class Services

In this paper, an adaptive transmission scheme is proposed to improve the spectral efficiency of TDMA systems. Services accommodated in such systems are classified as QoS services and BE services. Unlike conventional adaptive TDMA systems where the time slot duration is fixed for each user, our proposed system employs transmission slots with adaptive duration. For QoS services, rate adaptive modulation is adopted to make use of the instantaneous channel conditions of individual user. For BE services, a media access control strategy (MAC) that takes the instantaneous transmission conditions of all physical links of all BE services into consideration is employed. A framework to study the proposed system in terms of the average packet loss and the average system throughput is presented. The maximum number of QoS services that can be supported in the system while a predefined requirement on the average packet loss is still satisfied is investigated. A comparison study shows that our proposed scheme has higher system throughput over both conventional fixed and adaptive TDMA systems. Ronghong Mo received her B.Sc. and M. Sc. Degree from Zhongshan University, Guangzhou, China, both in Physics. From July 1999 to July 2003, she was a research scholar in the department of Electrical and Computer Engineering in National University of Singapore (NUS), toward her PhD degree. She is currently working as a research engineer in NUS. Her research interests include adaptive modulation, synchronization and channel estimation in wireless communications. Yong Huat Chew received the B.Eng, M.Eng and Ph.D. degrees in Electrical Engineering from National University of Singapore, Singapore. Since 1996, he has been with the Institute for Infocomm Research (formerly also known as Center for Wireless Communications and Institute for Communications Research), an institute under Agency for Science, Technology and Research, where he is presently a lead Scientist. His research interests are in wireless communications, transmission over HFC, DSL and all-optical networks.     

用于DMD显示系统的运动自适应去隔行技术

介绍基于数字微镜器件数字微镜器件显示系统的去隔行技术.去隔行算法通过对帧间差别的中值滤波完成运动自适应内插.位平面数据流经脉宽调制以逐行扫描速率驱动DMD显示.扫描行视频处理器可实时完成该功能.     

引入形态学处理的去隔行自适应算法

分析了现有的各种去隔行算法,在此基础上,将形态学处理引入基于运动检测的自适应去隔行技术中,对隔行图像进行精确的场内插值,通过运动检测将图像中的像素进行分类,针对不同类型的像素点自适应采取不同的插值算法.     

大气对上靶激光能量密度影响的分析

大气湍流与大气消光会给激光传输带来较大的影响。本文以激光的上靶功率密度为标准,大量分析表明：在一定的靶距范围内,激光发射系统不需要自适应光学系统进行波前校正。这对于有关激光武器的实际使用很有价值。     

基于热传导理论的背景抑制算法应用研究

针对复杂背景中红外运动目标检测速度慢,检测概率低的问题,对红外图像的背景和目标特性进行了分析,提出了一种基于热传导方程和自适应阈值的红外目标实时检测算法。首先,依据红外图像背景具有各向同性的分形特性,确定采用各向同性的算子对背景进行估计;然后,根据热传导方程和反热传导方程在图像处理中的应用,推导出了用于红外目标检测的背景抑制算子,在此基础上设计了自适应阈值用于红外目标的检测;最后给出了该算法的实验结果,并与基于特征选择性滤波的检测算法做了比较。实验结果表明该算法具有良好的背景抑制和目标增强性能,大幅提升了图像的信噪比,提高了红外运动目标的检测概率,且结构简单,有利于硬件实时实现。