宽带DDS设计与实现

介绍了直接数字合成器(DDS)原理。针对传统DDS工作频率低,瞬时带宽窄,杂散大等缺点,讨论了基于现场可编程门阵列(FPGA)的并行处理技术设计宽带DDS,利用高速数/模转换器(DAC)和大规模现场可编程门阵列(FPGA)实现了宽带DDS模块的设计,在宽带干扰机、宽带雷达信号波型产生器设计等领域具有广泛的应用前景。     

一种基于软件无线电的电子侦察干扰机

本文叙述了一种用于干扰线性调频连续波压缩雷达的基于宽带中频带通采样软件无线电结构的电子侦察干扰机。这种干扰机在数字信号处理器中对雷达信号进行短时傅里叶变换,测量雷达信号参数,然后根据干扰策略———距离波门拖引干扰,控制DDS产生干扰信号。最后利用Matlab进行仿真实验,证明这种方法能够有效干扰线性调频连续波压缩雷达。     

弹载电子干扰机作战效能仿真评估

为评估弹载干扰机的作战效能,在干扰评估准则的基础上,建立干扰、探测模型,通过分析反导系统于目标导弹之间的关系,提出最小干扰距离指标,并对几种典型反导武器系统的探测雷达进行干扰效果仿真计算,分析其在最小干扰距离指标下的干信比,得出弹载干扰机的作战效能。该研究对现代高技术战争条件下导弹攻防对抗具有实际意义和应用价值。     

某投掷式干扰机的结构设计

以炮弹为运载平台将干扰机投掷到目标区需完成炮射、空中开舱、落地、天线展开等系列动作,才能有效地开展后续工作。文中介绍了干扰弹的组成和工作流程,通过仿真分析、优化结构设计、结构设计创新、采用灌封工艺、静态和动态试验相结合等手段,进行工程化设计。试验结果表明,干扰机能可靠有效地工作,达到了设计要求。     

噪声压制式手机干扰机设计

手机通信的失密、泄密问题无论在军事上还是在商业竞争上都显得日益严峻,同时也向保密技术和电子对抗技术提出了极大的挑战.防止通过手机的失密行为最直接的方法就是在必要时对一定空间范围内的手机进行干扰,切断其与基站的联系,从而使外界的任何通信工具和接收设备都无法获得手机的信息.为此,设计了一种结构简单的可用于小型保密会议的遮盖式噪声调频手机干扰机.详细介绍了该手机干扰机的设计原理,分析了达到阻塞手机通信所需的干扰功率,实现了样机并给出了测试结果.实验结果表明,对面积为50 m2的室内手机通信干扰,效果良好.     

基于邻频干扰的802.11干扰机设计与实现

基于无线网络交叠信道邻频间干扰及802.11 DCF机制,在合理挑选干扰频道、尽量减少网卡跳变次数的基础上,设计并实现一种高效灵活的全频道干扰机。该干扰机配置有2个网卡,网卡a进行信道监测,网卡b根据网卡a返回的信道号差值数据,跳转到预置的干扰频道发送干扰信号,通过调节干扰信号发送速率实现不同的干扰概率。实验结果表明,该干扰机具有灵活、节能,可覆盖全13个频道的特点。     

成像雷达干扰机效能验证平台的设计与实现

随着以合成孔径雷达(SAR)为代表的成像雷达技术的快速发展,成像雷达在军事上得到越来越多的广泛利用,因此对其有效的干扰措施也得到了广泛研究。由于SAR雷达应用上的特殊性,对其干扰措施的效果评估也有其独特之处。根据SAR的成像技术特点,提出了一种成像雷达干扰机效能验证平台。     

Topology control in the presence of jammers for wireless sensor networks

In this paper, the problem of ensuring packet delivery ratio and high network lifetime in wireless sensor networks in the presence of single or multiple jammers is studied using single‐leader‐multiple‐followers Stackelberg game theory. A topology control scheme is proposed, in which the sink node, which acts as the leader, identifies the set of jamming affected nodes. On the other hand, the sensor nodes, which act as followers, need to decide an optimum transmission power level, while ensuring an optimal set of neighbor nodes covered. A scheme, named TC‐JAM, for ensuring packet delivery ratio, while avoiding jammers and increasing network lifetime in wireless sensor networks, is proposed. In existing literatures, the sensor nodes are envisioned to be equipped with multiple interfaces, while having access for multiple channels. However, in TC‐JAM, the sensor nodes have simple hardware with single interface for communication, ie, the sensor nodes have single channel for communication. Additionally, in the proposed scheme, TC‐JAM, each sensor node has a provision to vary its transmission power according to the chosen strategies. Using TC‐JAM, the energy consumption of the overall network reduces by up to 62%, and the network lifetime increases by 56% to 73%.     

小型无人机机载通信干扰机控制系统设计与实现

设计了小型无人机机载通信干扰机的控制系统。主机采用ＭＣＳ－５１系列单片机,实现数据采样、实时处理、分析判断和遥控参数预置等功能。对提高系统可靠性进行了较深入的研究。所设计的系统适应无人机干扰系统灵活多变的战术要求。试飞结果证明了系统设计的正确有效     

Joint reactive jammer detection and localization in an enterprise WiFi network

The deployment of wireless networks for Internet connectivity has been rapid during the last decade. Following this trend, enterprises utilize multiple access points (APs) in order to provide wireless connectivity to authorized users within its premises. However, wireless networks are extremely vulnerable to PHY/MAC layer attacks such as jamming. A jammer transmits electromagnetic energy on the medium in order to either block the access to any legitimate transmitter or cause collisions at the receiver (or both). One of the most advanced jamming models is that of reactive jamming. A reactive jammer does not constantly transmit energy on the air, but only jams when a legitimate (target) packet is on the medium, aiming at its collision at the receiver. Previous studies have shown that reactive jamming is one of the most difficult attack models to detect. In this work, we propose a scheme that performs both detection and localization of a reactive jammer in an enterprise WiFi network. In brief, a reactive jammer can virtually increase the interference range of the target AP and thus increase the busy times of nearby APs that use the same frequency. By quantifying this effect we are able to accurately detect the presence of a reactive jammer and perform a coarse grain localization of the jammer. Our simulation results show that our scheme can achieve high true positives and low false positives simultaneously. In addition, our coarse grain localization scheme exhibits error on the order of the AP coverage area.