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1.
基于DRFM的脉冲多普勒雷达组合干扰及其效能评估   总被引:2,自引:0,他引:2  
脉冲多普勒雷达具有较强的抗干扰能力,对其实施有效干扰有一定的困难。本文仿真研究了两种基于数字射频存储器的脉冲多普勒雷达组合干扰技术,并分别提出了脉冲多普勒雷达压制性干扰和欺骗性干扰的干扰效果度量方法,该方法在具体应用场合更贴近于干扰抗干扰的动态对抗过程。  相似文献   

2.
GPS抗干扰性能的分析有助于研究GPS干扰方法和手段。基于目前空域滤波的GPS抗干扰技术,采用LCMV算法对圆形天线阵的GPS抗干扰性能进行分析仿真,并提出了对其进行干扰的方法。在Matlab中对单个干扰源和多个干扰源在不同情况下的干扰效果进行仿真,仿真结果表明,LCMV算法能有效判定信号来波方位,并对干扰信号具有一定的赋零深度;针对分析结果提出多方位逼近干扰方法,能大幅降低LCMV获取的抗干扰增益。该方法对实战中采用空域滤波抗干扰技术的GPS干扰能提供一定的参考。  相似文献   

3.
依据地面防空对抗系统特点,确立了地面对抗系统作战中目标分配原则,运用军事运筹理论,建立了地面防空对抗系统干扰资源优化分配模型。给出了基于遗传算法的模型求解方法及步骤,并进行了实例仿真,得出最佳干扰资源分配方案。仿真证明了该方法有效、可行,对地面防空对抗系统干扰资源优化分配决策研究具有一定的参考价值。  相似文献   

4.
自适应地波超视距雷达高频通信干扰抑制   总被引:12,自引:11,他引:1  
苏洪涛  保铮  张守宏 《电波科学学报》2003,18(3):270-274,285
利用高频地波超视距雷达中高频通信干扰强度大、具有一定的方向性、属于瞬态干扰和其对地波雷达所有探测距离单元均有影响的特点,提出了自适应抑制短波通信干扰的方法。该方法利用无目标(海浪)单元的样本值估计阵列的协方差矩阵,进而利用自适应波束形成的方法对待测距离单元中的短波通信干扰进行滤除。对实测数据的处理结果表明,其能够有效的抑制高频通信干扰.  相似文献   

5.
通信对抗中干扰效能的准确评估对于优化干扰样式具有十分重要的作用。传统的误码率评估技术在卫星测控通信装备的电子对抗试验中具有一定的局限性。对此,本文提出了基于隐匿帧锁定状态转换的干扰效能评估方法,分析了帧状态转换与误码率之间的对应关系,并通过仿真验证了该方法的有效性与实用性。这对于卫星测控通信装备电子对抗试验中的干扰效果评价体系的建立具有重要意义。  相似文献   

6.
为了在电子战系统中对敌方星载合成孔径雷达(SAR)雷达进行有效干扰,文中提出了一种新颖的星载SAR欺骗式干扰信号的实时产生技术。该技术首先通过对分布式大场景的干扰调制函数的离线及分块并行计算,降低了干扰信号产生的复杂度和计算量; 然后,通过实时卷积产生欺骗干扰信号,从而实现对敌方星载SAR系统的实时欺骗干扰的目的; 最后,试验干扰机的测试数据和仿真结果说明了方法的有效性。结果表明:该方法不但可以提供可信赖的干扰效果,而且在实践应用中具有一定的实时性。  相似文献   

7.
基于移相调制的合成孔径雷达虚假图像干扰   总被引:12,自引:0,他引:12  
提出一种新的合成孔径雷达有源欺骗干扰方法———基于移相调制的合成孔径雷达虚假图像干扰。对该方法的干扰原理进行了深入分析并进行了仿真实验。研究表明 ,新方法可以产生覆盖一定区域的包含大量地物信息的虚假图像 ,欺骗干扰效果远强于传统的虚假点目标干扰 ,具有很好的应用前景。  相似文献   

8.
对全球定位系统GPS的干扰在电子对抗领域具有十分重要的地位。文章从GPS定位原理出发,从理论上说明了GPS定位系统与四星时差无源定位系统的一致性,通过时差定位方程论述了时延伪GPS卫星干扰的定位控制原理,分析了伪卫星数目所带来的定位误差的变化,并通过仿真验证了该原理的正确性与有效性,这对于该干扰样式的工程实现具有一定的指导意义。  相似文献   

9.
该文首先在码片匹配滤波的基础上提出4种数据选择方案,分析了各种数据方案对多址干扰与字符间干扰的影响;接着提出了基于Rosen梯度投影实现的最小均方和最小二乘两种盲空时多用户检测方法,并分析了4种数据选择方案对这两种检测方法运算复杂度的影响;最后通过仿真实验结果的分析比较给出较合理的实现方法,该方法在运算量,收敛速度和性能上具有一定的优势,因而更加具有实用意义。  相似文献   

10.
一种SAR压制干扰效果评估方法   总被引:15,自引:1,他引:14  
马俊霞  蔡英武  张海 《现代雷达》2004,26(10):4-6,31
对SAR干扰效果的评估是比较复杂和困难的,目前国内外的公开报道中未见到好的评估方法。从欧几里德距离空间的概念出发,提出了一种对SAR压制干扰效果的评估方法。文章就几种典型的噪声压制干扰模式对SAR的干扰进行了计算机仿真,并采用该方法与传统的评估方法对干扰效果进行了对比评估。结果表明,该评估方法具有客观、定量、一致性好的优点。  相似文献   

11.
Voice conversion (VC) based on Gaussian mixture model (GMM) is the most classic and common method which converts the source spectrum to target spectrum. However this method is prone to over-fitting because of its frame-by-frame conversion. The VC with non-negative matrix factorization (NMF) is presented in this paper, which can keep spectrum from over-fitting by adjusting the size of basis vector (dictionary). In order to realize the non-linear mapping better, kernel NMF (KNMF) is adopted to achieve spectrum mapping. In addition, to increase the accuracy of conversion, KNMF combined with GMM (GKNMF) is also introduced into VC. In the end, KNMF, GKNMF, GMM, principal component regression (PCR), PCR combined with GMM (GPCR), partial least square regression (PLSR), NMF correlation-based frequency warping (NMF-CFW) and deep neural network (DNN) methods are compared with each other. The proposed GKNMF gets better performance in both objective evaluation and subjective evaluation.  相似文献   

12.
蔡喜平 《中国激光》2006,33(6):19-822
研究了一种基于激光干涉技术的瞬态热力学量测量方法,可用于测量由于光激发产生的瞬时反应热及反应体积。介绍了利用干涉技术测量化学反应热量及反应体积的基本原理。实验中以肌红蛋白(Mb)为研究对象,由于肌红蛋白受光激发后,会与CO发生化学反应,导致系统的热力学量发生变化,从而引起系统折射率的变化。折射率变化会引起干涉相位变化。通过测量相位变化,可以获得肌红蛋白受光激发后热力学量的变化信息。在273~301 K温度范围内进行了肌红蛋白与CO的反应实验,测量了肌红蛋白与CO在10-6~10-1s窗口的化学反应。测得的反应热量与体积分别为80 kJ/mol和10 mL/mol。  相似文献   

13.
A Multicarrier phase-coded (MCPC)waveform design scheme with two steps for Joint radar and communication (JRC) system is developed.Firstly,an integrated MCPC waveform design method is addressed by simultaneously maximizing the Signal-to-clutter-to-noise ratio (SCNR) and the Shannon capacity,subject to both the Integrated sidelobe level ratio (ISLR) constraint and the energy constraint.This model is theoretically proved to be a convex optimization problem with respect to the absolute squares of the transmit weights corresponding to different subcarriers,of which the analytical result is also discussed.Subsequently,by further optimizing the phases of the transmit weights,minimizing the Peak to average power ratio (PAPR) for JRC system is recast as a Semidefinite programming (SDP) problem,which can be effectively solved with the Semidefinite relaxation(SDR) technique via Eigenvalue decomposition (EVD)or Complex Gaussian randomization (CGR).Numerical examples are provided to verify the effectiveness of the proposed scheme.  相似文献   

14.
Software-Defined Network(SDN)empowers the evolution of Internet with the OpenFlow,Network Virtualization and Service Slicing strategies.With the fast increasing requirements of Mobile Internet services,the Internet and Mobile Networks go to the convergence.Mobile Networks can also get benefits from the SDN evolution to fulfill the Sth Generation(5G) capacity booming.The article implements SDN into Frameless Network Architecture(FNA) for5G Mobile Network evolution with proposed Mobile-oriented OpenFlow Protocol(MOFP).The Control Plane/User Plane(CP/UP)separation and adaptation strategy is proposed to support the User-Centric scenario in FNA.The traditional Base Station is separated with Central Processing Entity(CPE) and Antenna Element(AE) to perform the OpenFlow and Network Virtualization.The AEs are released as new resources for serving users.The mobile-oriented Service Slicing with different Quality of Service(QoS) classification is proposed and Resource Pooling based Virtualized Radio Resource Management(VRRM) is optimized for the Service Slicing strategy with resource-limited feature in Mobile Networks.The capacity gains are provided to show the merits of SDN based FNA.And the MiniNet based Trial Network with Service Slicing is implemented with experimental results.  相似文献   

15.
Introducing multiple-input multiple-output (MIMO) relay channel could offer significant capacity gain.And it is of great importance to develop effective power allocation strategies to achieve power efficiency and improve channel capacity in amplify-and-forward relay system.This article investigates a two-hop MIMO relay system with multiple antennas in relay node (RN) and receiver (RX).Maximizing capacity with antenna selection (MCAS) and maximizing capacity with eigen-decomposition (MCED) schemes are proposed to efficiently allocate power among antennas in RN under first and second hop limited scenarios.The analysis and simulation results show that both MCED and MCAS can improve the channel capacity compared with uniform power allocation (UPA) scheme in most of the studied areas.The MCAS bears comparison with MCED with an acceptable capacity loss, but lowers the complexity by saving channel state information (CSI) feedback to the transmitter (TX).Moreover, when the RN is close to RX, the performance of UPA is also close to the upper bound as the performance of first hop is limited.  相似文献   

16.
Trace N, N-dimethylformamide(DMF) containing composite polymer electrolytes (CPEs) has attracted much attention owing to the dramatically increased Li+-conductivity. But the amount of DMF is critical and needs to be clarified for the interfacial stability, since DMF is easily reduced by Li-metal. Herein, the influences of DMF in poly(ethylene oxide) (PEO) and poly(vinylidene fluoride) (PVDF) based CPEs are studied on the Li+-conductivity and interfacial stability. In PEO-based CPEs, owing to a stronger interaction of lithium bis(trifluoromethanesulfon)imide (LiTFSI) with PEO than DMF, DMF can not be confined and be easily evaporated off. Only ≈0.25wt.% DMF is absorbed on ceramic electrolyte fillers, giving two times increased Li+-conductivity compared with the DMF-free counterparts and generating stable interface with Li-metal; but over much DMF (≥2.2 wt.%) leads to serious interfacial reactions with Li-metal. While in PVDF-based CPEs, ≈8wt.% DMF is confined by LiTFSI owing to a stronger interaction of LiTFSI with DMF than with PVDF. Short-term stable interface with Li-metal can be obtained, but longer-term cycling or higher current density leads to the gradually aggravated reactions with Li-metal. Thanks to the high-voltage stability of PVDF based CPEs, better cycling performance is obtained when they are used as catholytes to match high-voltage cathodes.  相似文献   

17.
The next generation wireless access technology highly relies on nonorthogonal multiple access (NOMA) technique. This paper proposes a novel power domain cyclic spread multiple access (PDCSMA) scheme for the design of NOMA system with power domain superposition coding (SC) and cyclic spreading at the transmitter concurrent with symbol level successive interference cancellation (SL‐SIC) at the receiver. Based on acceptable difference in channel gain, the users are grouped together to form PDCSMA clusters, and the unique power is allotted to each user in a cluster. The user with good channel condition is allotted less power, and the user with poor channel condition is allotted more power. Each PDCSMA cluster has its own spreading code, and the data of every user in a cluster are cyclic spread with the same code. Each cluster supports the number of multipath components equivalent to the length of the spreading code. The use of cyclic spreading makes the signal suffered by multipath fading less prone to intra cluster interference. The user signal is decoded by minimum mean square error‐frequency domain equalization (MMSE‐FDE) or maximal ratio combining (MRC)–based receiver in which weak user is detected with hard decision, and strong user is detected with SIC. Compared with conventional power domain NOMA (PDNOMA) and interleaved NOMA, the proposed PDCSMA achieves better bit error rate (BER) performance and assures guaranteed detection.  相似文献   

18.
ABSTRACT

Orthogonal Frequency Division Multiplexing (OFDM) is a widely used technique for wireless communications. But uncoded OFDM is not sufficient by itself, that is why channel coding is included to increase the system performance. In this study, concatenated Bose Chaudhuri Hocquenghem (BCH) and Convolutional Coded (CC) OFDM system is investigated for multipath fading channel with Additive White Gaussian Noise (AWGN). The simulation results show that the proposed concatenated code needs lower Signal-to-Noise Ratio (SNR) when compared with single BCH code, single convolutional code and even with other concatenated systems. Throughout the simulations BCH coding is performed with 128, 256, 512 Fast Fourier Transform (FFT) lengths; whereas convolutional coding is performed with 1/2, 1/3 coding rates. Furthermore, interleavers are added to the system to prevent the burst errors that occur over the channel. With the proposed system, the best result is obtained by using BCH(511,340) and CC(3,1,7) concatenation which is 8.2 dB SNR value for 10?3 Bit Error Rate (BER). This result is very close to ideal AWGN channel value, which is 8 dB for 10?3 BER.  相似文献   

19.
This paper describes the fabrication of a nanostructured heterojunction of two conjugated polymers by a three‐step process: i) spin‐coating a multilayered film of the two polymers, ii) rolling the film into a cylinder (a “jelly roll”) and iii) sectioning the film perpendicular to the axis of the roll with an ultramicrotome (nanoskiving). The conjugated polymers are poly(benzimidazobenzophenanthroline ladder) (BBL, n‐type) and poly(2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene) (MEH‐PPV, p‐type). The procedure produces sections with an interdigitated junction of the two polymers. The spacing between the phases is determined by spin‐coating (~15 nm to 100 nm) and the thickness of each section is determined by the ultramicrotome (100 to 1000 nm). The minimum width of the MEH‐PPV layers accessible with this technique (~15 nm) is close to reported exciton diffusion lengths for the polymer. When placed in a junction between two electrodes with asymmetric work functions (tin‐doped indium oxide (ITO) coated with poly(3,4‐ethylenedioxythiophene:poly(styrenesulfonate) (PEDOT:PSS), and eutectic gallium‐indium, EGaIn) the heterostructures exhibit a photovoltaic response under white light, although the efficiency of conversion of optical to electrical energy is low. Selective excitation of BBL with red light confirms that the photovoltaic effect is the result of photoinduced charge transfer between BBL and MEH‐PPV.  相似文献   

20.
提出了一种高速、低功耗、高分辨率的新型Sigma-Delta模数转换器(ADC)结构。该结构选择过采样率(OSR)为32的4阶调制器设计以缓解输出速率和通带宽度的压力,采用级联和双量化的方法进行优化,并利用SIMSIDES工具(基于Simulink的Sigma-Delta仿真器)进行仿真。数字抽取滤波器部分由级联积分梳状(CIC)滤波器、有限长单位冲激响应(FIR)滤波器和半带(HB)滤波器组成,并且三级滤波器都采用了多相分解结构,以降低动态功耗。使用0.18μm的标准CMOS工艺实现数字抽取滤波器版图。仿真结果表明,在250 kHz带宽下,有效位宽(ENOB)为19 bit。  相似文献   

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