WorldWideScience

Sample records for anti-jamming

  1. Electromagnetic anti-jam telemetry tool

    Science.gov (United States)

    Ganesan, Harini; Mayzenberg, Nataliya

    2008-02-12

    A mud-pulse telemetry tool includes a tool housing, a motor disposed in the tool housing, and a magnetic coupling coupled to the motor and having an inner shaft and an outer shaft. The tool may also include a stator coupled to the tool housing, a restrictor disposed proximate the stator and coupled to the magnetic coupling, so that the restrictor and the stator adapted to generate selected pulses in a drilling fluid when the restrictor is selectively rotated. The tool may also include a first anti-jam magnet coupled to the too housing, and an second anti-jam magnet disposed proximate the first anti-jam magnet and coupled to the inner shaft and/or the outer shaft, wherein at least one of the first anti-jam magnet and the second anti-jam magnet is an electromagnet, and wherein the first anti-jam magnet and the second anti-jam magnet are positioned with adjacent like poles.

  2. Studies on Novel Anti-jamming Technique of Unmanned Aerial Vehicle Data Link

    Institute of Scientific and Technical Information of China (English)

    Huang Wenzhun; Wang Yongsheng; Ye Xiangyang

    2008-01-01

    Based on the M-ary spread spectrum (M-ary-SS), direct sequence spread spectrum (DS-SS), and orthogonal frequency division multiplex (OFDM), a novel anti-jamming scheme, named orthogonal code time division multi-subchannels spread spectrum modulation (OC-TDMSCSSM), is proposed to enhance the anti-jamming ability of the unmanned aerial vehicle (UAV) data link. The anti-jamming system with its mathematical model is presented first, and then the signal formats of transmitter and receiver are derived. The receiver's bit error rate (BER) is demonstrated and anti-jamming performance analysis is carried out in an additive white Ganssian noise (AWGN) channel. Theoretical research and simulation results show the anti-jamming performance of the proposed scheme better than that of the hybrid direct sequence frequency hopping spread spectrum (DS/FH SS) system. The jamming margin of the OC-TDMSCSSM system is 5 dB higher than that of DS/FH SS system under the condition of lUcian channel and full-band jamming, and 6 dB higher under the condition of Rician channel environment and partial-band jamming.

  3. Novel anti-jamming technique for OCDMA network through FWM in SOA based wavelength converter

    Science.gov (United States)

    Jyoti, Vishav; Kaler, R. S.

    2013-06-01

    In this paper, we propose a novel anti-jamming technique for optical code division multiple access (OCDMA) network through four wave mixing (FWM) in semiconductor optical amplifier (SOA) based wavelength converter. OCDMA signal can be easily jammed with high power jamming signal. It is shown that wavelength conversion through four wave mixing in SOA has improved capability of jamming resistance. It is observed that jammer has no effect on OCDMA network even at high jamming powers by using the proposed technique.

  4. Collaborative Anti-jamming in Cognitive Radio Networks Using Minimax-Q Learning

    Directory of Open Access Journals (Sweden)

    Sangeeta Singh

    2013-10-01

    Full Text Available Cognitive radio is an efficient technique for realization of dynamic spectrum access. Since in the cognitive radio network (CRN environment, the secondary users (SUs are susceptible to the random jammers, the security issue of the SU’s channel access becomes crucial for the CRN framework. The rapidly varying spectrum dynamics of CRN along with the jammer’s actions leads to challenging scenario. Stochastic zero-sum game and Markov decision process (MDP are generally used to model the scenario concerned. To learn the channel dynamics and the jammer’s strategy the SUs use reinforcement learning (RL algorithms, like Minimax-Q learning. In this paper, we have proposed the multi-agent multi-band collaborative anti-jamming among the SUs to combat single jammer using the Minimax-Q learning algorithm. The SUs collaborate via sharing the policies or episodes. Here, we have shown that the sharing of the learned policies or episodes enhances the learning probability of SUs about the jammer’s strategies but reward reduces as the cost of communication increases. Simulation results show improvement in learning probability of SU by using collaborative anti-jamming using Minimax-Q learning over single SU fighting the jammer scenario.

  5. AntiJam: Efficient Medium Access despite Adaptive and Reactive Jamming

    CERN Document Server

    Richa, Andrea; Schmid, Stefan; Zhang, Jin

    2010-01-01

    Intentional interference constitutes a major threat for communication networks operating over a shared medium and where availability is imperative. Jamming attacks are often simple and cheap to implement. In particular, today's jammers can perform physical carrier sensing in order to disrupt communication more efficiently, specially in a network of simple wireless devices such as sensor nodes, which usually operate over a single frequency (or a limited frequency band) and which cannot benefit from the use of spread spectrum or other more advanced technologies. This paper proposes the medium access (MAC) protocol \\textsc{AntiJam} that is provably robust against a powerful reactive adversary who can jam a $(1-\\epsilon)$-portion of the time steps, where $\\epsilon$ is an arbitrary constant. The adversary uses carrier sensing to make informed decisions on when it is most harmful to disrupt communications; moreover, we allow the adversary to be adaptive and to have complete knowledge of the entire protocol history....

  6. Space-borne antenna adaptive anti-jamming method based on gradient-genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel space-borne antenna adaptive anti-jamming method based on the genetic algorithm(GA), which is combined with gradient-like reproduction operators is presented,to search for the best weight for pattern synthesis in radio frequency(RF).Combined,the GA's the capability of the whole searching is,but not limited by selection of the initial parameter,with the gradient algorithm's advantage of fast searching.The proposed method requires a smaller sized initial population and lower computational complexity.Therefore,it is flexible to implement this method in the real-time systems.By using the proposed algorithm,the designer can efficiently control both main-lobe shaping and side-lobe level.Simulation results based on the spot survey data show that the algorithm proposed is efficient and feasible.

  7. Anti-jamming of Inverse Synthetic Aperture Radar based on Slope-varying Linear Frequency Modulation Signal

    Directory of Open Access Journals (Sweden)

    Zhu Yupeng

    2009-09-01

    Full Text Available Deceptive jamming technology against inverse synthetic aperture radar is matured now, which is meaningful in military application. But the research on anti-jamming technology for inverse synthetic aperture radar (ISAR is still not a mature technology. Through the analysis on the theory of deceptive jamming technology against ISAR, a new method for anti-jamming against ISAR based on linear frequency modulation signal’s frequency slope-varying is presented. The false target echo energy is suppressed due to frequency modulation slope mis-matching. Doppler domain averaging is adopted for improving the quality of the ISAR image, which helps automatic target recognition. Simulation result based on simulating data shows the validity of the new algorithm.Defence Science Journal, 2009, 59(5, pp.537-544, DOI:http://dx.doi.org/10.14429/dsj.59.1556

  8. An SDR-Based Real-Time Testbed for GNSS Adaptive Array Anti-Jamming Algorithms Accelerated by GPU.

    Science.gov (United States)

    Xu, Hailong; Cui, Xiaowei; Lu, Mingquan

    2016-01-01

    Nowadays, software-defined radio (SDR) has become a common approach to evaluate new algorithms. However, in the field of Global Navigation Satellite System (GNSS) adaptive array anti-jamming, previous work has been limited due to the high computational power demanded by adaptive algorithms, and often lack flexibility and configurability. In this paper, the design and implementation of an SDR-based real-time testbed for GNSS adaptive array anti-jamming accelerated by a Graphics Processing Unit (GPU) are documented. This testbed highlights itself as a feature-rich and extendible platform with great flexibility and configurability, as well as high computational performance. Both Space-Time Adaptive Processing (STAP) and Space-Frequency Adaptive Processing (SFAP) are implemented with a wide range of parameters. Raw data from as many as eight antenna elements can be processed in real-time in either an adaptive nulling or beamforming mode. To fully take advantage of the parallelism resource provided by the GPU, a batched method in programming is proposed. Tests and experiments are conducted to evaluate both the computational and anti-jamming performance. This platform can be used for research and prototyping, as well as a real product in certain applications. PMID:26978363

  9. An SDR-Based Real-Time Testbed for GNSS Adaptive Array Anti-Jamming Algorithms Accelerated by GPU

    Directory of Open Access Journals (Sweden)

    Hailong Xu

    2016-03-01

    Full Text Available Nowadays, software-defined radio (SDR has become a common approach to evaluate new algorithms. However, in the field of Global Navigation Satellite System (GNSS adaptive array anti-jamming, previous work has been limited due to the high computational power demanded by adaptive algorithms, and often lack flexibility and configurability. In this paper, the design and implementation of an SDR-based real-time testbed for GNSS adaptive array anti-jamming accelerated by a Graphics Processing Unit (GPU are documented. This testbed highlights itself as a feature-rich and extendible platform with great flexibility and configurability, as well as high computational performance. Both Space-Time Adaptive Processing (STAP and Space-Frequency Adaptive Processing (SFAP are implemented with a wide range of parameters. Raw data from as many as eight antenna elements can be processed in real-time in either an adaptive nulling or beamforming mode. To fully take advantage of the parallelism resource provided by the GPU, a batched method in programming is proposed. Tests and experiments are conducted to evaluate both the computational and anti-jamming performance. This platform can be used for research and prototyping, as well as a real product in certain applications.

  10. Research on Evaluation of Netted Radar Anti-jamming Capability%雷达网抗干扰能力评估研究

    Institute of Scientific and Technical Information of China (English)

    周武; 董文锋; 许端

    2012-01-01

      为有效地评价雷达网的抗电子干扰能力,在层次分析法评估雷达抗干扰能力的基础上,综合考虑干扰条件下单部雷达的抗干扰能力以及雷达网的附加抗干扰能力,提出了评估雷达网抗干扰能力的表达式;最后给出了实例分析和评估。评估结果验证了该表达式用来度量雷达网抗干扰能力是有效的。%  In order to evaluate effectively the anti-jamming capability of netted radars, on the basis of using AHP to evaluate anti-jamming capability of radar and having an overall consideration of the single radar anti-jamming and the netted radars’additional anti-jamming capabilities, this paper presents an expression of anti-jamming capability of netted radars, and gives its example analysis and evaluation. Evaluation results show that the proposed expression can be effective in measuring the anti-jamming capability of netted radars.

  11. A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

    Directory of Open Access Journals (Sweden)

    Dennis Akos

    2011-09-01

    Full Text Available Due to their weak received signal power, Global Positioning System (GPS signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs. However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU coupled with a new generation Graphics Processing Unit (GPU having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities.

  12. A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

    Science.gov (United States)

    Seo, Jiwon; Chen, Yu-Hsuan; De Lorenzo, David S.; Lo, Sherman; Enge, Per; Akos, Dennis; Lee, Jiyun

    2011-01-01

    Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities. PMID:22164116

  13. Anti-jamming Design for Mobile Command System Communication%机动式指挥系统通信抗干扰设计

    Institute of Scientific and Technical Information of China (English)

    孔令涛; 常冬友

    2011-01-01

    为了对抗敌方的各种通信干扰,机动式指挥系统通信传输必须综合应用各种抗干扰措施,提升抗干扰能力。介绍了机动式指挥系统通信传输业务类型以及各类通信手段传榆性能,在此基础上,重点介绍了提高机动式指挥系统通信抗干扰能力的几种方法,并给出了具体实例。%To counter various jamming technologies for the enemy, a mobile command system needs to integrate different kinds of anti-jamming technology to improve its anti-jamming capability. This paper firstly introduces different operation types of mobile command system communication and the performance of each transmission method. Then, several methods for improving the anti-jamming capability of mobile command system communication are introduced and implementation cases are given.

  14. 无人机角跟踪系统抗干扰性能分析%Analysis on Anti-jamming Performance of Angle Tracking System of UAV

    Institute of Scientific and Technical Information of China (English)

    盛怀洁; 廖明飞

    2014-01-01

    The anti-jamming performance of TT&C system of UAV is mostly decided by that of its angle tracking system. In this paper,the classification of angle tracking system of UAV is studied. The qualitative analysis on the interference response of system is done.Four specifications of anti-jamming performance of system are put forward based on classification of interference response.The defi-nitions and the calculation methods of specifications are given,and their physical significance is elaborated. The method of quantitative analysis of anti-jamming performance of system is proposed.%无人机角跟踪系统的抗干扰性能很大程度上决定了无人机测控系统的抗干扰性能。研究了无人机角跟踪系统的体制分类,定性分析了系统对干扰的干扰响应,在干扰响应分类的基础上提出了4个系统抗干扰性能指标,并对各指标进行了定义。给出了指标计算方法,阐明了指标的物理意义,提出了无人机角跟踪系统抗干扰性能定量分析的方法。

  15. Research on Anti-jamming RF-EAS System%射频EAS系统的抗干扰研究

    Institute of Scientific and Technical Information of China (English)

    李威; 邓计才

    2014-01-01

    At present, the market of RF-EAS systems is still very large, accompanied by an increasingly serious electromagnetic interference the anti-jamming performance of it also faces greater challenges. This thesis takes AIO (All-In-One) type of RF-EAS systems as the object to study how to improve its anti-interference performance. Interference noise in the article is divided into two types, which are steady noise and transient noise. According to the characteristics of different interference noises, their impacts on all aspects of the system are fully analyzed, and then, we propose a series of targeted hardware and software measures. Finally, the self-adaptability of the system is studied, and we present a feasible way to improve the anti-interference ability and stability of the system.%目前,射频EAS系统的市场应用仍十分广泛,伴随着日益严重的电磁干扰,其抗干扰性能面临着更大的挑战。此文针对一体式射频EAS系统如何提高其抗干扰性能进行研究。根据不同干扰噪声的特点,对稳态干扰和瞬时干扰在系统工作的各个环节上的影响进行分析,有针对性地给出了一系列包括硬件和软件等方面的方法,提出了一种以信噪比为基础提高系统自适应能力的算法,并结合实验仿真进行了验证,结果表明,本方法提升了系统的抗干扰能力和稳定性。

  16. Overview of research on key techniques for anti-jamming of UAV data link%UAV数据链抗干扰的关键技术研究综述

    Institute of Scientific and Technical Information of China (English)

    李思佳; 毛玉泉; 郑秋容; 李波

    2011-01-01

    无人机(unmanned aerial vehicle,UAV)数据链抗干扰功能的增强是UAV实现战时信息资源共享的核心目标.在分析现有无人机数据链研究现状的基础上,重点综述了UAV数据链抗干扰功能的两类方案:一是在单链路方面,对现有UAV数据链的信道编/解码技术作了比较,并对其他抗干扰现状进行了研究;二是多链路方面,对多链路组网的抗干扰技术进行了深入分析,综述了协同通信在多链路UAV数据链中的应用.抗干扰关键技术的综述为下一代UAV数据链的研发提供一定的理论与技术基础.%The key goal of sharing martial information resources is to enhance the anti-jamming function of UAV data link.Based on analyzing actuality of UAV data link, overviewed two issues for anti-jamming of UAV data link.Firstly, made a comparison of methods for channel code of current UAV data link and performed an overview of researches on anti-jamming techniques.Secondly, analyzed a review of anti-jamming techniques using in multi-link network.Lastly, presented an overview of application research on cooperative communication in the multi-link network of the UAV data link.Provided some kinds of foundation for next generation UAV data link through the overview of research on theoretic and techniques.

  17. 某型雷达宽-限-窄电路噪声调频抗干扰措施研究%Research into Frequency Modulated Noise Anti-jamming Measure Based on WBDF Circuit for Certain Radar

    Institute of Scientific and Technical Information of China (English)

    袁佳杰; 谢乘峰

    2012-01-01

    This paper quantitatively analyzes the operational performance of pulse Doppler (PD) radar adopting the anti-jamming countermeasure based on wideband dicke-fix (WBDF) circuit in the frequency modulated noise jamming environment, compares with the operational performance of the radar without any anti-jamming measures, obtains the factors effeeting on the radar operational performance in the jamming environment,validates the validity of this anti-jamming measure.%定量分析了脉冲多普勒(PD)雷达采用宽-限-窄电路抗干扰措施后在调频噪声干扰环境中的工作性能,与该雷达未采用抗干扰措施时的工作性能进行了对比,得到了干扰环境中影响雷达工作性能的因素,验证了该抗干扰措施的有效性。

  18. 改进SDM算法在CAN总线通信卡抗干扰设计中的应用%SDM Algorithm in the Application of the Communication Card Anti-jamming Design

    Institute of Scientific and Technical Information of China (English)

    顾名宇

    2014-01-01

    提出了一种基于改进SDM通信卡抗干扰算法,分析了经典SDM算法,该种算法在有噪情况以及严重噪声干扰系统的情况下,信号分离质量大大降低,无法准确恢复有价值信号,改进后的SDM算法采用双态信道模型获取通信卡的平均误码率,实现对通信卡干扰情况下信号传递的控制,是一种有效的抗干扰算法。仿真实验结果说明,改进SDM方法下通信卡的抗干扰性远远高于经典SDM方法,是一种稳健的通信卡抗干扰方法。%This paper proposes a algorithm based on improved SDM communication card anti-interference, analyzed the classical algorithm of SDM, this kind of algorithm for noise and serious noise of signal separation quality is greatly re-duced, unable to recover valuable signal accurately, improve SDM algorithm USES binary channel model for the average ber communication card, realize the communication card interference signals under control, is a kind of effective anti-jamming algorithm. Simulation experiment results show that, to improve the anti-jamming of communication card under the SDM method is higher than classical SDM method, anti-jamming method is a robust communication card.

  19. 利用惯导信息的反舰末制导雷达抗干扰方法%The Anti-jamming Approach of the Anti-ship Terminal Radar Aided by INS Information

    Institute of Scientific and Technical Information of China (English)

    来庆福; 刘义; 赵晶; 冯德军; 王雪松

    2011-01-01

    Featured characteristic of ineitial navigation system (INS) information, as short-term accuracy, ultra stability and self-determination, cannot be disturbed by electromagnetic interference. In light of these traits, a novel information processing approach aided by INS position and velocity information for anti-jamming application was proposed,. Based on missile-to-target relative motion model, during the terminal guidance tracking phase of anti-ship missile (ASM), target position and velocity information could be obtained by extended Kalman filtering to suppress seeker random measurement errors. When the jamming was detected, one can combine target position forecast with INS navigation solution to accomplish the homing guidance of ASM, which could help achieve one's purpose of anti-jamming. Simulation was carried out in the presence of a maneuvering ship target, and it shows that this method is effective and feasible because of its preferable anti-jamming performance.%惯导信息短期精度高、稳定性好,且自主工作,不受外界电磁干扰.基于惯导的这些特点,提出了一种利用惯导位置、速度信息辅助抗舷外干扰的信息处理方法:在反舰导弹末制导跟踪阶段,建立弹目相对运动模型,通过扩展卡尔曼滤波降低雷达导引头随机测量误差,获取目标位置和速度信息,当检测到干扰,通过对目标位置的预测和惯导对导弹位置的确定,实现对导弹的制导,以达到抗干扰的目的.在考虑舰船目标机动情况下进行了仿真实验,仿真结果表明了该抗干扰方法是有效和可行的.

  20. 信息化条件下短波通信抗干扰技术与应用%Technology and Application Research of HF Communication Anti-jamming under the Informatization Condition

    Institute of Scientific and Technical Information of China (English)

    王磊; 李鹤; 周音; 郝强

    2012-01-01

    HF communication is one of the most important means of communication to protect the operational command information un- der the informatization condition, to improve its anti~amming capability is the essential part to ensure the smooth flow of battle command information. This paper analyzes the characteristics of HF communication and the importance of antiamming in HF communications, taking the spread spectrum communication system for example, explains the basic theory of communication anti-jamming, analysis of the various types of interference in HF communication and the corresponding anti-jamming technology, and lists the domestic and foreign technology and equipment which have been developed. Finally, with the requirements of future information warfare and the needs of communication in war- time, the trends of the future HF communication anti-jamming technology are introduced.%短波通信是信息化条件下保障作战指挥的重要通信手段,提高其抗干扰能力是保证作战指挥信息系统稳定的必要环节。文章首先分析了短波通信的特点和短波通信抗干扰的重要性;以扩谱通信抗干扰体制为例阐述了通信抗干扰的基本理论;分析了短波通信中的各类干扰,并针对这些干扰指出了各种抗干扰技术手段,同时列举了国内外已研发的相关技术装备;最后,结合未来信息化战争的要求和战时的通信需求,阐述了未来短波通信抗干扰技术的发展趋势。

  1. 基于认知无线电的通信抗干扰应用研究%Research on the Application of Anti-jamming based on Cognitive Radio

    Institute of Scientific and Technical Information of China (English)

    余鹏

    2015-01-01

    Cognitive Radio technology are put forward to provide a kind of effective way for solving the contradiction between wireless spectrum resources increasingly tense and of the growing demand for wireless communications applications. The basic concept and the key technology of cognitive radio are introduced, focuses on the analysis of cognitive radio in communication anti jamming strategy is applied and its advantages, to promote the rapid development of communication countermeasure equipment has positive significance.%认知无线电(Cognitive Radio,CR)技术的提出,为解决不断增长的无线通信应用需求与日益紧张的无线频谱资源之间的矛盾提供了一种有效的解决途径。介绍了认知无线电的基本概念和关键技术,重点分析了认知无线电在通信抗干扰中的应用策略及其优势,对促进通信对抗装备的快速发展具有积极意义。

  2. 低压电力线载波通信与抗干扰解决途径%Solutions for low-voltage power line carrier communication and anti-jamming

    Institute of Scientific and Technical Information of China (English)

    赵新正; 姚发久; 白崇乾; 王阳

    2014-01-01

    Since the power grid is the largest,most popular and reliable network,data transmission through low-voltage power line is the most economical way to use the existing resource. The technology for low-voltage power line multi-frequency self-adaption DSSS carrier communication was created by Shaanxi Kaistar Company,in which the development of IC chip and thick film circuit were included. The jamming from low-voltage power line was completely solved on the basis of the data concentrator, data acquisition unit,data controller and anti-jamming products. The application of power line carrier communication in the energy resources measurement and monitoring platform is superior to the other technologies.%电网是最大、最普及、最可靠的供电网,利用低压电力线实现数据传输,具有利用现有资源、减少投资的现实意义。陕西凯星公司独创了低压电力线多频段自适应直接序列展频载波通信技术,从IC芯片、厚膜电路的研发,从电力线载波数据集中器、采集器、控制器及抗干扰硬件产品入手,彻底解决了低压电力线上的干扰问题。该技术应用在能源计量监控平台方面,是其他技术无法比拟的。

  3. Anti-jamming in a fungal transport network

    CERN Document Server

    Hickey, Patrick C; Foshe, Sierra; Roper, Marcus

    2016-01-01

    Congestion limits the efficiency of transport networks ranging from highways to the internet. Fungal hyphal networks are studied as an examples of optimal biological transport networks, but the scheduling and direction of traffic to avoid congestion has not been examined. We show here that the Neurospora crassa fungal network exhibits anticongestion: more densely packed nuclei flow faster along hyphal highways, and transported nuclei self-organize into fast flowing solitons. Concentrated transport by solitons may allow cells to cycle between growing and acting as transport conduits.

  4. Novel microstrip antenna array for anti-jam satellite navigation system

    OpenAIRE

    Martynyuk, Sergiy Ye.; Vasylenko, Dmytro O.; Dubrovka, Fedor F.; Laush, Anatolii G.

    2015-01-01

    We present results of theoretical and experimental investigations of a novel dual band right hand circularly polarized microstrip antenna array with adaptive space-time processing capability for terminal of GPS/GLONASS/GALILEO satellite navigation systems. The array structure is composed from 10 microstrip radiators excited independently via separate coaxial input ports. Two central radiating elements for two frequency bands (L1 and L2) have got circular shapes with slits and are stacked to p...

  5. GPS Jamming: Strengthening Anti Jam GPS System with Adaptive Phase Only Nulling Using Cuckoo Search

    Directory of Open Access Journals (Sweden)

    V. Thyagarajan

    2014-08-01

    Full Text Available Global Positioning System (GPS signals are spread spectrum, modulated with very low average power caused by background noise. Signal received is mostly 165 dB down than thermal noise level. Such signals are easily jammed either through intentional noise sources (jammer or unintentionally from broadcasting stations harmonics or other out of band sources. This study proposes to reveal how a nulling antenna with adaptive spatial filtering technique can efficiently mitigate intentional and non-intentional interference. A beam forming antenna array is an antennas set whose outputs are weighted by complex values and combined form array output. The complex valued weights effect is to steer the array pattern’s main lobes to desired directions which may be unknown and hence antenna weights are adjusted adaptively till some array performance measure is improved, revealing proper lobe or null placement. This study proposes a Cuckoo Search (CS algorithm based new optimization method for multiple interference cancellation design that increases gain to desired signal and improves jamming rejection performance.

  6. A Preliminary Study on CSAMT Anti-jamming Transmitter System%CSAMT发射系统抗干扰供电技术初步研究

    Institute of Scientific and Technical Information of China (English)

    李荡; 王珺璐; 李勇; 李建华; 林品荣

    2016-01-01

    在伪随机编码信号的相关辨识理论基础上,根据可控源音频大地电磁法(CSAM T )测量频率范围及受环境电磁干扰影响的程度,将 CSAM T 测量划分为三个频段,对易受工频及其谐波成分干扰的频段采用伪随机编码发射,高频和低频段采用单频方波发射。发射系统的人机交互和供电波形的产生基于虚拟仪器 LabVIEW(Laboratory Virtual Instrumentation Engineer‐ing Workbench ,实验室虚拟仪器工程平台)软件平台,操作方便、控制灵活。%On the basis of the relevant identification theory of pseudo‐random code signal ,the signals of CSAM T ( Con‐trolled Source Audio‐Frequency Magneto Tellurics) are divided into three parts according frequency range and the extent affect ‐ed by environmental electromagnetic interference .The signals are susceptible to 50Hz interference signal and its harmonic com‐ponents should be set by pseudo‐random code way .Others are set by single square waveform way .The human‐computer inter‐action and waveform generated software of the transmitter system is built on the advanced virtual instrument platform ,Lab‐VIEW (Laboratory Virtual Instrumentation Engineering Workbench ) .The software is easy to operation and flexible to control .

  7. Research on the Anti-jamming Capabilities for Shortwave of Frequency Hopping Radion%短波跳频电台抗干扰性能

    Institute of Scientific and Technical Information of China (English)

    李国建; 张海勇

    2004-01-01

    短波跳频电台在军事通信中占有重要的地位,它能够确保通信的抗干扰性和隐蔽性.为正确利用短波跳频电台必须对短波跳频电台的抗干扰性能进行研究,分析了短波跳频电台的特点,研究了其抗干扰性能.得出了短波跳频电台的抗干扰性能与跳频电台的跳速、跳频带宽、跳频点数之间的关系,对正确应用短波跳频电台和提高其战斗效能具有重要意义.

  8. 电路和分组交换的抗干扰能力分析%Anti-jamming Capability Analysis of Circuit-switch & Packet-switch

    Institute of Scientific and Technical Information of China (English)

    骆连合; 曹彦军; 冯晓东

    2008-01-01

    随着军事信息在现代战争中作用的不断提高,以扰乱或破坏信息传送为目的的通信干扰的作用和地位也随之不断提高.通过对电路交换网络和分组交换网络在被干扰的情况下在物理层、链路层、信令和协议,以及通信业务的影响进行了分析和对比,得出在强干扰模式下网络保障性能大体一致,但是在某些条件下反应的特性分组网络略强.最后指出通信系统本身技术体制的选取是其抗干扰能力好坏的一个重要因素.

  9. 基于二进制人工蜂群算法的通信抗干扰决策方法%Anti-Jamming Communication Decision Method based on Binary Artificial Bee Colony Algorithm

    Institute of Scientific and Technical Information of China (English)

    惠显杨; 陈建忠; 牛英滔; 齐扬阳

    2016-01-01

    为实现通信抗干扰决策引擎自主调整系统参数的功能,借鉴了一种群体智能优化算法——二进制人工蜂群(binary artificial bee colony,BABC)算法,提出了基于二进制人工蜂群算法的通信抗干扰决策方法.该算法通过模拟蜜蜂采蜜的行为在搜索域中进行寻优,来实现对通信参数的自主选择.针对现有决策算法的不足,该算法对抗干扰决策过程中的目标函数进行合理的设置,使其更加符合实际的通信场景.仿真表明,该算法能够实现通信参数的最优选择,同时能够较好的防止局部最优;与已有的基本遗传算法(genetic algorithm,GA)和粒子群算法(particle swarm optimization,PSO)相比,该算法具有较好的收敛性能.

  10. A Study of Medium-sized Group of Soccer Robots Anti-jamming System%中型组足球机器人抗干扰系统的研究

    Institute of Scientific and Technical Information of China (English)

    钱晟; 毛丽民; 张亚飞; 浦宇欢

    2012-01-01

      提出了结合RGB和HSI色彩空间的颜色算法以减少光照干扰,基于HSI颜色模型对图像进行二值处理消除噪声;根据实际现场环境,选取最佳方案消除场周围的颜色干扰。实际运行测试表明了该方法的有效性。%  The vision subsystem is one of the most important parts in the football robot system. The vision sub⁃system mainly includes real-time, accuracy and adaptability. This paper completes the anti-interference process⁃ing mainly from three aspects. The First is light interference. The paper uses a color extract algorithm which combines RGB color space and HSI color space. Using RGB color model to collect image, it is transformed into HSI color model immediately. The HSI color model is not sensitive to light, so it can be used for color calibra⁃tion. The second is the color impurity. Based on the HSI color model, the picture is dealt with to eliminate the noise by erosion and dilation. The authors of this paper select the most appropriate spatial color model conver⁃sion to reduce impurities interference effects. The third is some color interference surrounding the match field. Some solutions have been reached in this paper. According to the actual environment, the best one is selected to eliminate environmental interference. The actual running tests show the effectiveness of the image process method.

  11. Research on jamming and anti-jamming technologies in military wireless communication%军用无线通信干扰与抗干扰技术研究

    Institute of Scientific and Technical Information of China (English)

    梁涛

    2015-01-01

    Since wireless communication is the main information transmission method in war,its viability in complex elec⁃tromagnetic environment decides the ability of reliable information transmission directly. To capture information superiority in war and improve system fighting capability based on information system,jamming and anti⁃jamming technologies become the re⁃search emphasis of all military powers in the world. In this paper,the conception,principle and characteristics of jamming methods in military wireless communication are introduced,and also the main anti⁃jamming technologies are presented. The current anti⁃jamming technologies in military wireless communication are analyzed with the example of Link⁃16 tactical data link.%无线通信是战时的主要信息传输手段,其在复杂电磁环境下的生存能力直接决定了交战双方的信息可靠传送能力。因此,为了夺取战时的信息优势,提高基于信息系统的体系作战能力,干扰技术和抗干扰技术成为了世界各军事强国通信技术的研究重点。首先介绍军用无线通信主要干扰手段的概念、原理、特点等,其次介绍针对目前干扰手段的主要抗干扰技术,最后以Link⁃16战术数据链为例,对目前军用无线通信抗干扰技术进行了分析。

  12. Software Anti-jamming Technology in Application of the Design of Monolithic Integrated Circuit System%软件抗干扰技术在单片机系统设计中的应用

    Institute of Scientific and Technical Information of China (English)

    崔萃

    2009-01-01

    该文探讨了软件抗干扰技术研究的主要问题,系统分析了单片机系统设计中的软件抗干扰技术,对常用的指令冗余、拦截以及看门狗等设计方法进行了深入研究,并给出了具体的实现方法,对实际应用具有一定的指导作用.

  13. The Anti-jamming Measures of Low Voltage Power Line Carrier Communication%低压电力线载波系统中的抗干扰措施

    Institute of Scientific and Technical Information of China (English)

    马宏锋; 陈金鹏

    2001-01-01

    According to the noises and interference in low power line, thispaper takes the measures from hardware and software. And it fits very well for restraining the noises and interference. It has been applied to the low vol tage power line carrier communication system, and obtained the anticipated effect.%根据低压电力线路存在的各种噪声和干扰,从硬件和软件等方面提出了相应的解决方案,并在低压电力线载波数据传输系统中得以应用,取得了预期的效果。

  14. Tracking Launch Vehicles in Interference and Jamming Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MARK Resources proposes to develop a method for combining a set of distributed FRPAs into a network that provides high GPS anti-jam/interference capability. Like a...

  15. Satellite-borne QPSK Direct Modulator for Ka Band

    Science.gov (United States)

    Zhang, Min; Li, Changsheng

    2016-02-01

    Ka band is referred to a microwave band whose frequency range is from 24.6 GHz to 40 GHz, it shares a wide available bandwidth, high frequency reuse rate and strong ability of anti-jamming. This paper presents a novel method to design a modulator for Ka-band satellite communication. Using QPSK to improve the ability of anti-jamming, using direct modulation to reduce the weight, volume and cost of electronic equipment, using sub-harmonic mixer to cut the LO power leakage, excellent modulation results are obtained.

  16. In PT6964 Chip as Display Driver EFT Interference Measures%以PT6964芯片作为显示驱动的EFT抗干扰措施

    Institute of Scientific and Technical Information of China (English)

    廖炎光

    2014-01-01

    This paper introduces the display driver chip microcontroller with PT6964LED in the application of several anti-jamming measures.%主要介绍了单片机与PT6964LED显示驱动芯片在应用中的几种抗干扰措施。

  17. Enabling short fragments for uncoordinated spread spectrum communication

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Pöpper, Christina; Capkun, Srdjan

    2014-01-01

    Uncoordinated spread spectrum (USS) protocols have been proposed for anti-jamming communication in wireless settings without shared secrets. The existing USS protocols assume that fragments of hundreds of bits can be transmitted on different channels in order to identify fragments that belong to...

  18. A Hybrid Structured Multistage Wiener Filter for GPS Interference Suppression

    Directory of Open Access Journals (Sweden)

    Qing-Dong Huang

    2013-11-01

    Full Text Available To suppress the influence of impulsive noise spikes (outliers from the direction of arrival of the desired GPS signals, a combination of the Householder multistage Wiener filter (HMSWF and the recently introduced Minimum Module Cascaded Canceller (MMCC is employed to compose a hybrid structured HMSWF (HS-HMSWF method. The enhanced algorithm is employed by space-time anti-jamming processing in GPS receiver, with the ability of natural protection against the impulsive noise spikes influence of weights calculation. In space signal processing, it can avoid the zero pitch formed at the direction of target signal, and prevent the desired signal be diminished. Simulation results demonstrated the favorable anti-jamming performance of the proposed algorithm.  

  19. Weighing and control of bulk material in ship-lading process at harbor

    International Nuclear Information System (INIS)

    The author describes a new weighing and control system for bulk material in ship-loading process at harbor. It adopts nuclear radiation measurement, computer control and digital signal process techniques to weigh the bulk material with no-touch with the advantages of stability and anti-jamming. The measure accuracy reaches to 0.5% - 1.0%. It is was applicable in the bad condition of ship-loading spot at harbor

  20. Advancements on Radar Polarization Information Acquisition and Processing

    Directory of Open Access Journals (Sweden)

    Dai Dahai

    2016-04-01

    Full Text Available The study on radar polarization information acquisition and processing has currently been one important part of radar techniques. The development of the polarization theory is simply reviewed firstly. Subsequently, some key techniques which include polarization measurement, polarization anti-jamming, polarization recognition, imaging and parameters inversion using radar polarimetry are emphatically analyzed in this paper. The basic theories, the present states and the development trends of these key techniques are presented and some meaningful conclusions are derived.

  1. Precise Location Technology Based on Chirp Spread Spectrum

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2011-06-01

    Full Text Available This article introduces chirp spread spectrum technology (CSS for short and optimized location algorithm. Symmetric double-sided two way ranging technique (SDS–TWR for short is applied to improve accuracy and range of measurement. Linear frequency modulation ranging technology utilizes protocols combining CSMA / CA and TDMA, and adjusts dynamically transmission rate and frame length according to noise, interference and multipath to ensure optimal throughput and accurate distance information. System has anti-jamming capability and covers great distance.

  2. New Type Multielectrode Capacitance Sensor for Liquid Level

    International Nuclear Information System (INIS)

    This paper introduces the design of a new type multielectrode capacitance sensor for liquid level. The system regards electric field sensor MC33794 as the core and applies microcontroller MC9S12DJ128 to realize intelligent liquid level monitoring system, which overcomes the disadvantages of the traditional capacitance sensor, improves on the anti-jamming ability and the measurement precision and simplifies the system structure. Finally, the paper sums up the design of the system

  3. Design and Implementation of a Wireless Sensor Network-Based Remote Water-Level Monitoring System

    OpenAIRE

    Li, Xiuhong; Cheng, Xiao; Gong, Peng; Yan, Ke

    2011-01-01

    The proposed remote water-level monitoring system (RWMS) consists of a field sensor module, a base station module, adata center module and aWEB releasing module. It has advantages in real time and synchronized remote control, expandability, and anti-jamming capabilities. The RWMS can realize real-time remote monitoring, providing early warning of events and protection of the safety of monitoring personnel under certain dangerous circumstances. This system has been successfully applied in Poya...

  4. Intelligent cognitive radio jamming - a game-theoretical approach

    Science.gov (United States)

    Dabcevic, Kresimir; Betancourt, Alejandro; Marcenaro, Lucio; Regazzoni, Carlo S.

    2014-12-01

    Cognitive radio (CR) promises to be a solution for the spectrum underutilization problems. However, security issues pertaining to cognitive radio technology are still an understudied topic. One of the prevailing such issues are intelligent radio frequency (RF) jamming attacks, where adversaries are able to exploit on-the-fly reconfigurability potentials and learning mechanisms of cognitive radios in order to devise and deploy advanced jamming tactics. In this paper, we use a game-theoretical approach to analyze jamming/anti-jamming behavior between cognitive radio systems. A non-zero-sum game with incomplete information on an opponent's strategy and payoff is modelled as an extension of Markov decision process (MDP). Learning algorithms based on adaptive payoff play and fictitious play are considered. A combination of frequency hopping and power alteration is deployed as an anti-jamming scheme. A real-life software-defined radio (SDR) platform is used in order to perform measurements useful for quantifying the jamming impacts, as well as to infer relevant hardware-related properties. Results of these measurements are then used as parameters for the modelled jamming/anti-jamming game and are compared to the Nash equilibrium of the game. Simulation results indicate, among other, the benefit provided to the jammer when it is employed with the spectrum sensing algorithm in proactive frequency hopping and power alteration schemes.

  5. 基于平均可工作概率的星间链路整网抗干扰性能评估方法%Performance evaluation method based on average availability for inter-satellite links system

    Institute of Scientific and Technical Information of China (English)

    韩其位; 聂俊伟; 刘文祥; 王飞雪

    2013-01-01

    Independent and autonomous running of the entire GNSS system in navigation warfare is one of the most important aims of building inter-satellite links.However,it is inevitable that inter-satellite links will be faced with the threats from jams in navigation warfare,which may result in performance declining,or even breaking down.Therefore,exact evaluation of anti-jamming performance is very important.Anti-jamming performance evaluation of inter-satellite links system is much more difficult than other objects,as it is related to almost every aspect of the system,such as the design of signal system,network,linking strategy,equipment performance,and so on.In order to accurately evaluate the antiinterference performance of the entire inter-satellite links network under the conditions of navigation warfare,this study firstly analyzed a variety of factors which affect the anti-jamming performance of inter-satellite links.On this basis,test scenarios for anti-jamming performance evaluation was modeled and designed.And then an evaluation method for anti-jamming performance of inter-satellite links system based on average availability was proposed,and the index system for availability evaluation was defined,which made accurate and quantitative evaluation of anti-jamming performnce of the entire inter-satellite links network possible.%导航战条件下的全系统自主导航运行是卫星导航系统星间链路建设的重要目标之一.对星间链路在导航战情况下的工作性能进行准确评估具有非常重要的意义.星间链路的整网抗干扰性能与单星抗干扰能力、星间信号体制、建链策略、网络体制等多种因素均有关系,比较复杂,从而为其准确评估带来很大困难.为准确评估导航战条件下星间链路的整网抗干扰性能,对影响星间链路整网抗干扰性能的各种因素进行分析,并在此基础上对整网抗干扰性能评估场景进行建模设计.提出了以干扰场景遍历条件

  6. A method of initial welding position guiding for arc welding robot based on visual servo control

    Institute of Scientific and Technical Information of China (English)

    郭振民; 陈善本; 邱涛; 吴林

    2003-01-01

    In order to solve the visual guiding task of initial welding position for arc welding robot, this paper presents a practice-prone image-based visual servo control strategy without calibration, and we perform validating experiments on a nine-DOF arc welding robot system. Experimental results illustrate presented method has the function to fulfill the task of welding robot initial positioning with certain anti-jamming ability. This method provides a basis for guiding welding gun to initial welding pose with real typical seam's image properties to replace flag block properties, and is a significant exploit to realize visual guiding of initial welding position and seam tracing in robot welding system.

  7. Application of the Algorithm of Fractional Dimension to Extraction Image Edge

    Institute of Scientific and Technical Information of China (English)

    Qiang Luo; Qingli Ren

    2006-01-01

    The idea of fractional dimension was stated in brief firstly. Then, adopting the fractional statistical similar principle,the method of the least square minimum error was applied to evaluate the fractional dimension of per image pixel depending on the fractional property of image. And the image edge is extracted by magnitude of fractional dimension of image pixel. We presented the algorithm of the local fractional dimension, which made the rule of window size and sentencing the fractional dimension of edge. Although this algorithm was waste time, it is better than the classical ones in extraction edge and anti-jamming.

  8. Jamming in the Internet of Things: A Game-Theoretic Perspective

    OpenAIRE

    Namvar, Nima; Saad, Walid; Bahadori, Niloofar; Kelley, Brian

    2016-01-01

    Due to its scale and largely interconnected nature, the Internet of Things (IoT) will be vulnerable to a number of security threats that range from physical layer attacks to network layer attacks. In this paper, a novel anti-jamming strategy for OFDM-based IoT systems is proposed which enables an IoT controller to protect the IoT devices against a malicious radio jammer. The interaction between the controller node and the jammer is modeled as a Colonel Blotto game with continuous and asymmetr...

  9. Controllable clock circuit design in PEM system

    International Nuclear Information System (INIS)

    A high-precision synchronized clock circuit design will be presented, which can supply steady, reliable and anti-jamming clock signal for the data acquirement (DAQ) system of Positron Emission Mammography (PEM). This circuit design is based on the Single-Chip Microcomputer and high-precision clock chip, and can achieve multiple controllable clock signals. The jamming between the clock signals can be reduced greatly with the differential transmission. Meanwhile, the adoption of CAN bus control in the clock circuit can prompt the clock signals to be transmitted or masked simultaneously when needed. (authors)

  10. Design of CAN Bus Dashboard on Mini EV%电动微型汽车的CAN总线仪表板设计

    Institute of Scientific and Technical Information of China (English)

    王秀青

    2012-01-01

    基于CAN总线技术设计完成了电动微型汽车仪表板,并针对CAN总线技术的优势进行了论述.同时简要介绍了仪表板采用的抗干扰措施。%The dashboard on mini EV has been designed based on the CAN bus technology, the advantages of that are described and the anti-jamming measures for the dashboard are briefly introduced.

  11. Design principle of integrated direct digital sensor of rotation rate and torque

    Science.gov (United States)

    Zhang, Xiaoning; Geng, Chunming; Fu, Yongling

    2006-11-01

    Based on measuring technique of ordinary sensor of rotation rate and torque, this article mainly studied the sensing element of CMF (Coriolis Mass-Flow Meter), and designed for the prototype an IDDSRT (Integrated Direct Digital Sensor of Rotation Rate and Torque) that consists of torsion-bar spring, measuring fluted disc, and photoelectric sensing device. The sensor measures with high-frequency pulse. This design reduces the factors that affect the measuring, completely realizes non-contact digital measurement, greatly improves the anti-jamming ability and the measuring stability, and therefore increases measuring accuracy.

  12. Key of Packaged Grain Quantity RECOGNITION——RESEARCH on Processing and Describing of ``FISH and Describing of ``FISH Scale Body''

    Science.gov (United States)

    Lin, Ying; Fang, Xinglin; Sun, Yueheng; Sun, Yanhong

    The key to identifying the packaged grain is the shape of package, and the key to identifying shape is processing and describing the boundary of package. Based on a lot of analysis and experiment, this article select the canny operator and chain code to process and describe the boundary of package. Aiming at the boundary is not absolute connectivity, the closure operation of Mathematical Morphology is introduced to do pretreatment on binary image of packaged grain. Finally the boundary is absolute connectivity. Experiments show that the proposed method enhances the anti-jamming and robustness of edge detection.

  13. Key of Packaged Grain Quantity Recognition - - Research on Processing and Describing of "fish and Describing of "fish Scale Body"

    Science.gov (United States)

    Lin, Ying; Fang, Xinglin; Sun, Yueheng; Sun, Yanhong

    The key to identifying the packaged grain is the shape of package, and the key to identifying shape is processing and describing the boundary of package. Based on a lot of analysis and experiment, this article select the canny operator and chain code to process and describe the boundary of package. Aiming at the boundary is not absolute connectivity, the closure operation of Mathematical Morphology is introduced to do pretreatment on binary image of packaged grain. Finally the boundary is absolute connectivity. Experiments show that the proposed method enhances the anti-jamming and robustness of edge detection.

  14. The Development of Intelligent Detector for Train Longitudinal Impact

    Institute of Scientific and Technical Information of China (English)

    TIAN E; MO Yimin; NIU Wei

    2006-01-01

    This paper introduces a new kind of train impact detecting system that detect the train impact through detecting the train running acceleration, proposes that uniting the train running acceleration and the change rate of acceleration to token the train impact. The detector takes the portable computer as platform of data processing, utilizes the database technology to process data, making instrument Pc true, and improving the data processing ability of the instrument. The detector can show the train running acceleration on-line and real-timely, indicating the train impact situation directly,and uses the method that the software and hardware unifies to strengthen the system anti-jamming ability. At present, this detector has been tryout in some locomotive depots, each design function and the performance index conforms to request of the scene; the anti-jamming ability is strong, the monitor precision is reasonable, the detector can carry out the on-line examination to the train impact and monitoring the train running condition.

  15. Communication and control technology of underwater vehicle%水下机器人通信与控制技术研究

    Institute of Scientific and Technical Information of China (English)

    杨薇

    2015-01-01

    Research the development process of underwater vehicle, this article proposed vehicle system design with a track and designed the automotive module and algorithm control. Then contrast pulse modulation, differential pulse modulation, made use of improved underwater communication DPPM. Finally, experiments show that this method improves the data transfer rate. Add white noise to simulation experiment. When the signal is superimposed, anti-jamming capability of system would first become strong, with the increase in data, anti-jamming capability was weakened.%通过调研水下机器人的发展历程,提出了带有履带机器人的系统设计方案,并对其车载模块进行设计以及算法控制。然后通过对脉冲调制、差分脉冲调制进行对比,提出利用改进的 DPPM 进行水下通信,最后通过实验说明此种方法提高了数据的传输速率,添加白噪声进行实验仿真,说明当信号因延迟为叠加时,系统抗干扰能力会先变强,然后随着叠加数据的增多,抗干扰性减弱。

  16. Cascade connection serial parallel hybrid acquisition synchronization method for DS-FHSS in air-ground data link

    Science.gov (United States)

    Wang, Feng; Zhou, Desuo

    2007-11-01

    In air-ground tactical data link system, a kind of primary anti jamming technology adopted is direct sequence - frequency hopping spread spectrum (DS-FHSS) technology. However, how to implement the quick synchronization of DS-FHSS is an important technology problem, which could influence the whole communication capability of system. Thinking of the application demand of anti jamming technology in actual, a kind of cascade connection serial parallel hybrid acquisition synchronization method is given for the DS-FHSS system. The synchronization consists of two stages. The synchronization of FH communication is adopted at the first stage, and the serial parallel hybrid structure is adopted for the DS PN code synchronization at the secondary stage. Through calculating the detect probability of the FH synchronization acquisition and the acquisition time of DS code chip synchronization, the contribution to the synchronization capability of system by this method in this paper is analyzed. Finally, through simulating on computer, the performance estimate about this cascade connection serial parallel hybrid acquisition synchronization method is given.

  17. Mathematical principle and characteristics of polarization transform

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The precise definition of polarization transform is proposed from the viewpoint of polarization domain transform for the first time. The mathematical principle,char-acteristics and physical meanings of polarization transform are analyzed. Two typical kinds of polarization transforms which are called unitary matrix polarization transform (UMPT) and diagonal matrix polarization transform (DMPT) are put for-ward. The gain property and the change property of polarization state distance are presented in detail. Thereby,the concept of serial polarization transform is pro-posed. A general polarization transform can be realized by two steps: changing the location of polarization states in polarization domain by UMPT; and expanding or compressing the density of polarization states by DMPT. The result is meaningful to many applications including polarization filtering,detection,enhancement,anti-jamming,discrimination and so on.

  18. Measurement system for high voltage pulse power supply on HL-2A

    International Nuclear Information System (INIS)

    A measurement system for the high voltage pulse power supply on HL-2A has been developed. It adopts the voltage divider based on high-frequency inductance-free glaze film resistor along with the fiber isolation technology based on voltage-frequency conversion. Moreover, a DSP chip is used in the fiber transmission, to realize A/D conversion, simplifying the circuit, enhancing the data transmission speed and anti-jamming ability of the system. The system has been applied to long-pulse (5 s) discharge experiments on HL-2A. The experimental results show that, the system realizes the potential isolation for power supply, and the measured voltage waveforms reflect the supply output faithfully, providing real-time voltage data for the feedback and protection system of the supply. (authors)

  19. Packaged silica microsphere-taper coupling system for robust thermal sensing application.

    Science.gov (United States)

    Yan, Ying-Zhan; Zou, Chang-Ling; Yan, Shu-Bin; Sun, Fang-Wen; Ji, Zhe; Liu, Jun; Zhang, Yu-Guang; Wang, Li; Xue, Chen-Yang; Zhang, Wen-Dong; Han, Zheng-Fu; Xiong, Ji-Jun

    2011-03-28

    We propose and realize a novel packaged microsphere-taper coupling structure (PMTCS) with a high quality factor (Q) up to 5×10(6) by using the low refractive index (RI) ultraviolet (UV) glue as the coating material. The optical loss of the PMTCS is analyzed experimentally and theoretically, which indicate that the Q is limited by the glue absorption and the radiation loss. Moreover, to verify the practicability of the PMTCS, thermal sensing experiments are carried out, showing the excellent convenience and anti-jamming ability of the PMTCS with a high temperature resolution of 1.1×10(-3) ◦C. The experiments also demonstrate that the PMTCS holds predominant advantages, such as the robustness, mobility, isolation, and the PMTCS can maintain the high Q for a long time. The above advantages make the PMTCS strikingly attractive and potential in the fiber-integrated sensors and laser. PMID:21451600

  20. The risk early-warning of gas hazard in coal mine based on Rough Set-neural network

    Institute of Scientific and Technical Information of China (English)

    TIAN Shui-cheng; WANG Li

    2007-01-01

    This article proposed the risk early-warning model of gas hazard based on Rough Set and neural network. The attribute quantity was reduced by Rough Set, the main characteristic attributes were withdrawn, the complexity of neural network system and the computing time was reduced, as well. Because of fault-tolerant ability, parallel processing ability, anti-jamming ability and processing non-linear problem ability of neural network system, the methods of Rough Set and neural network were combined. The examples research indicate: applying Rough Set and BP neural network to the gas hazard risk early-warning coal mines in coal mine, the BPNN structure is greatly simplified, the network computation quantity is reduced and the convergence rate is speed up.

  1. [An experimental study of the computer-controlled equipment for delivering volatile anesthetic agent].

    Science.gov (United States)

    Sun, B; Li, W Z; Yue, Y; Jiang, C W; Xiao, L Y

    2001-11-01

    Our newly-designed computer-controlled equipment for delivering volatile anesthetic agent uses the subminiature singlechip processor as the central controlling unit. The variables, such as anesthesia method, anesthetic agent, the volume of respiratory loop, age of patient, sex, height, weight, environment temperature and the grade of ASA are all input from the keyboard. The anesthetic dosage, calculated by the singlechip processor, is converted into the signals controlling the pump to accurately deliver anesthetic agent into respiratory loop. We have designed an electrocircuit for the equipment to detect the status of the pump's operation, so we can assure of the safety and the stability of the equipment. The output precision of the equipment, with a good anti-jamming capability, is 1-2% for high flow anesthesia and 1-5% for closed-circuit anesthesia and its self-detecting working is reliable. PMID:12583263

  2. Direct GPS P-Code Acquisition Method Based on FFT

    Institute of Scientific and Technical Information of China (English)

    LI Hong; LU Mingquan; FENG Zhenming

    2008-01-01

    Recently, direct acquisition of GPS P-code has received considerable attention to enhance the anti-jamming and anti-spoofing capabilities of GPS receivers. This paper describes a P-code acquisition method that uses block searches with large-scale FFT to search code phases and carrier frequency offsets in parallel. To limit memory use, especially when implemented in hardware, only the largest correlation result with its position information was preserved after searching a block of resolution cells in both the time and frequency domains. A second search was used to solve the code phase slip problem induced by the code frequency offset. Simulation results demonstrate that the probability of detection is above 0.99 for carrier-to-noise density ratios in excess of 40 dB- Hz when the predetection integration time is 0.8 ms and 6 non-coherent integrations are used in the analysis.

  3. Isothermal amplification detection of nucleic acids by a double-nicked beacon.

    Science.gov (United States)

    Shi, Chao; Zhou, Meiling; Pan, Mei; Zhong, Guilin; Ma, Cuiping

    2016-03-01

    Isothermal and rapid amplification detection of nucleic acids is an important technology in environmental monitoring, foodborne pathogen detection, and point-of-care clinical diagnostics. Here we have developed a novel method of isothermal signal amplification for single-stranded DNA (ssDNA) detection. The ssDNA target could be used as an initiator, coupled with a double-nicked molecular beacon, to originate amplification cycles, achieving cascade signal amplification. In addition, the method showed good specificity and strong anti-jamming capability. Overall, it is a one-pot and isothermal strand displacement amplification method without the requirement of a stepwise procedure, which greatly simplifies the experimental procedure and decreases the probability of contamination of samples. With its advantages, the method would be very useful to detect nucleic acids in point-of-care or field use. PMID:26706801

  4. Strategy and Consider for Hosting Type Data Center Users%托管数据中心用户的策略和考虑

    Institute of Scientific and Technical Information of China (English)

    陈宇通

    2012-01-01

    主要阐述了用户如何决策使用托管型的数据中心。并从安全性、节能、抗干扰、高效安装等几方面对布线设计和方案实施提出了合理化建议,以给数据中心用户决策提供参考。%The user to how to carry on the decision-making for use hosting type data center was mainly discussed. And some rational suggestions for wiring design and plan implementation were given, from the aspects of safety, energy saving, anti-jamming, high efficiency installation. It can provide references for users' decision making.

  5. Design of object surveillance system based on enhanced fish-eye lens

    Institute of Scientific and Technical Information of China (English)

    Jianhui Wu; Kuntao Yang; Qiaolian Xiang; Nanyang Zhang

    2009-01-01

    A new method is proposed for the object surveillance system based on the enhanced fish-eye lens and the high speed digital signal processor (DSP). The improved fish-eye lens images an ellipse picture on the charge-coupled device (CCD) surface, which increases both the utilization rate of the 4:3 rectangular CCD and the imaging resolution, and remains the view angle of 183°. The algorithm of auto-adapted renewal background subtraction (ARBS) is also explored to extract the object from the monitoring image. The experimental result shows that the ARBS algorithm has high anti-jamming ability and high resolution, leading to excellent object detecting ability from the enhanced elliptical fish-eye image under varies en-vironments. This system has potential applications in different security monitoring fields due to its wide monitoring space, simple structure, working stability, and reliability.

  6. Research on a Sort of Ultrasonic Flowmeter%一种超声流量计的设计

    Institute of Scientific and Technical Information of China (English)

    乔静

    2012-01-01

    In this paper,an ultrasonic flowmeter is designed by the use of difference method.It can measure gas flux,which can avoid the shortcoming of touching flowmeter such as short utility time and discommodious installing.It has high precision,good anti-jamming ability and bright prospects for application.%本文采用时差法设计了一种超声流量计,用于测量气体的体积流量,避免了接触式流量计寿命短、安装不方便等缺点。该设计精度高,抗干扰能力强,具有广阔的应用前景。

  7. The development of micro-gyroscope technology

    International Nuclear Information System (INIS)

    This review reports an overview and development of micro-gyroscope. The review first presents different types of micro-gyroscopes. Micro-gyroscopes in this review are categorized into Coriolis gyroscope, levitated rotor gyroscope, Sagnac gyroscope, nuclear magnetic resonance (NMR) gyroscope according to the working principle. Different principles, structures, materials, fabrications and control technologies of micro-gyroscopes are analyzed. This review compares different classes of gyroscopes in the aspects such as fabrication method, detection axis, materials, size and so on. Finally, the review evaluates the key technologies on how to improve the precision and anti-jamming ability and to extend the available applications of the gyroscopes in the market and patents as well. (topical review)

  8. Brushless DC Motor Control System Design Based on DSP2812

    Directory of Open Access Journals (Sweden)

    Wei Min

    2016-01-01

    Full Text Available By comparison various control methods currently for permanent magnet brushless DC motor, on the basis of motor principle analysis, a current smallest and most real-time all-digital rare earth permanent magnet brushless DC motor control system is designed. The high-speed digital signal processor DSP2812 is applied as the main control unit. The fuzzy PID control algorithm is used to control rectifier regulator and speed, which the speed and current is double closed loop in the system. The principle of control system, control strategy and software is analyzed in this paper. The system has some features such as less overshoot, rapid response speed, good performance of anti-jamming, simple structure, high control precision, flexible in changing control policies and so on. Validity of the design is verified by prototype test.

  9. Power Transformer Intelligence Monitor System

    Institute of Scientific and Technical Information of China (English)

    Sun Jianshe; Shi Lei

    2006-01-01

    An auto-monitoring system has been created that could monitor the main parameter of power transformers. It reads data of V&I by precision rectifier circuit and amplifier, and converted electric energy into pulse signal by means of sensor technique and pulse converter circuit, it is sent into microcomputer to process, completed monitoring to power transformer parameters and running state by software system. It can register all kinds of key data, and provide all kinds of virtual technical data for managing sections and can auto-form all kinds of electric annual reports and monthly reports analysis graphs such as managing graphs. It notably improves the safety and reliability of transformer, with strong anti-jamming technique and unique function, it can be used on the transformers in railway' s self-closing lines and all kinds of transformer stations.

  10. Circular object recognition based on shape parameters

    Institute of Scientific and Technical Information of China (English)

    Chen Aijun; Li Jinzong; Zhu Bing

    2007-01-01

    To recognize circular objects rapidly in satellite remote sensing imagery, an approach using their geometry properties is presented.The original image is segmented to be a binary one by one dimension maximum entropy threshold algorithm and the binary image is labeled with an algorithm based on recursion technique.Then, shape parameters of all labeled regions are calculated and those regions with shape parameters satisfying certain conditions are recognized as circular objects.The algorithm is described in detail, and comparison experiments with the randomized Hough transformation (RHT) are also provided.The experimental results on synthetic images and real images show that the proposed method has the merits of fast recognition rate, high recognition efficiency and the ability of anti-noise and anti-jamming.In addition, the method performs well when some circular objects are little deformed and partly misshapen.

  11. Reed Solomon Coding for Frequency Hopping Spread Spectrum in Jamming Environment

    Directory of Open Access Journals (Sweden)

    Othman Sidek

    2008-01-01

    Full Text Available Frequency hopping spread spectrum with noncoherent M-ary frequency shift keying system is considered. In this study Reed Solomon codes RS (255, 223 are employed in a standard error correction role to provide some Anti-Jamming (AJ capability with 8-bit symbols. Noise has been added to RS encoded data, which is demodulated at RS decoder perfectly. Matlab simulations have been implemented for numerical results. Graphical results have been plotted between the probability of an erasure versus ρ using RS (255, 223 code for 1 and 2 kHz frequencies. The simulation results have proved that system having RS (255, 223 code with M = 32 require substantially less signal to jammer power ratio to achieve the same bit error probability.

  12. Guiding the welding robot to the initial welding position with visual method

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhenyou; Lin Tao; Chen Shanben

    2008-01-01

    Using step pattern match technology with variational resolution can recognize the position and orientation of the weld seam in the image. According to using the image segmentation method based on pattern match, not only advanced the speed and anti-jamming capability, but also captured the edge information of the weld seam and the edge of the workpiece, and the image coordinate of the initial welding position can be obtained. The matrix for hand-eye relationship of the robot can be calculated by adopting the rapid calculation method. According to the depth calculating principle with the special point matching using binocular stereovision, the initial welding position can be confirmed by calculating the middle point of the perpendicular line of two radials in the space, and the function to guide the welding robot to the initial welding position can be realized.

  13. Design of new seismometer based on laser Doppler effect

    Institute of Scientific and Technical Information of China (English)

    Zhenhui Du(杜振辉); Fuxiang Huang(黄福祥); Chengzhi Jiang(蒋诚志); Zhifei Tao(陶知非); Hua Gao(高华); Lina Lü(吕丽娜)

    2004-01-01

    In order to improve the resolution of seismic acquisition, a new seismic acquisition system based on tangential laser Doppler effect with an optimized differential optical configuration is proposed. The relative movement of the inertia object and the immobile frame is measured by laser Doppler effect, which can avoid the electromagnetic and thermometric interference, and the adoption of frequency-modulated (FM)transmission can improve the ability of anti-jamming. The frequency bandwidth is properly determined by analyzing the frequency of the Doppler signal. The velocity, displacement, acceleration, and frequency to be measured can be real-time acquired by frequency/velocity (F/V) converting the FM Doppler signal.A 100-dB dynamic range and the linear frequency range of 1.0 to 1000 Hz are realized.

  14. Research and application of visual location technology for solder paste printing based on machine vision

    Institute of Scientific and Technical Information of China (English)

    Luosi WEI; Zongxia JIAO

    2009-01-01

    A location system is very important for solder paste printing in the process of surface mount technology (SMT). Using machine vision technology to complete the location mission is new and very efficient. This paper presents an integrated visual location system for solder paste printing based on machine vision. The working principle of solder paste printing is introduced and then the design and implementation of the visual location system are described. In the system, two key techniques are completed by secondary development based on VisionPro.One is accurate image location solved by the pattern-based location algorithms of PatMax. The other one is camera calibration that is achieved by image warping technology through the checkerboard plate. Moreover, the system can provide good performances such as high image locating accuracy with 1/40 sub-pixels, high anti-jamming, and high-speed location of objects whose appearance is rotated, scaled, and/or stretched.

  15. A New Method to Improve the Precision of SO2Measurement in Atmosphere

    Science.gov (United States)

    Gong, R. K.; Chen, L.; Nian, S. P.

    2006-10-01

    The thesis discusses the status quo and existent problems of SO2 measurement, explores sensor mechanism of measurement precision of SO2, and deduces the mathematical measurement model of SO2 according to Lambert-Beer Law. Aiming at the nonlinearity problem existing in the mathematical model, it employs Taylor's series expansion to resolve the problem. In addition, it designs the gas room of double optical paths to measure SO2 by infrared, which utilizes four detectors to eliminate the impact of CO2 and disturbed noise by receiving signals. Finally, through the analysis of the experimental data, it proves that this method has such features as easy implementation, high precision, strong anti-jamming capability, and real-time and on-line measurement of SO2required in the industry field.

  16. Resilience of LTE networks against smart jamming attacks

    KAUST Repository

    Aziz, Farhan M.

    2014-12-08

    Commercial LTE networks are being studied for mission-critical applications, such as public safety and smart grid communications. In this paper, LTE networks are shown vulnerable to Denial-of-Service (DOS) and loss of service attacks from smart jammers, who may employ simple narrowband jamming techniques to attack without any need to hack the network or its users. We modeled the utilities of jamming and anti-jamming actions played by the jammer and the network under the framework of single-shot and repeated Bayesian games. In a single-shot game formulation the only Nash Equilibria (NE) are pure strategy equilibria at which network utility is severely compromised. We propose a repeated-game learning and strategy algorithm for the network that outperforms single-shot games by a significant margin. Furthermore, all of our proposed actions and algorithms can be implemented with current technology.

  17. Simulation of pulse modulated infrared air-to-air missile%脉冲调制式红外空空导弹仿真

    Institute of Scientific and Technical Information of China (English)

    黄鹤松; 童中翔; 李建勋; 王超哲; 柴世杰; 李慎波

    2014-01-01

    红外空空导弹仿真是空战效能评估的重点和难点。根据红外空空导弹的识别、制导、运动机理,建立了导弹模型,同时也建立了诱饵模型,对红外空空导弹进行仿真和抗干扰分析。该导弹模型主要由导引头制导方程组、导弹运动方程组、抗干扰方法等组成。根据建立的导弹模型仿真出了导弹的攻击区、导弹和靶机运动轨迹以及导弹的抗干扰性能,通过与真实导弹进行对比表明,仿真的红外空空导弹与真实的导弹性能指标基本吻合。%Infrared air-to-air missile simulation is an important and difficult part of air war performance evaluation.Based on identification,guidance,motion mechanism of infrared air-to-air missile,missile and infrared decoy model were established to simulation and anti-jamming analysis for infrared air-to-air missile.Missile model was composed by seeker guided equations,missile motion equations,anti-interference methods etc.Missile attack zone,missile and drone aircraft trajectories and anti-jamming performance were simulated according to the model.Contrasted with real missile,the calculation results are in good agreement with the experimental results.

  18. Performance analysis of DS/FH signals based on wideband ambiguity function%基于宽带模糊函数的DS/FH信号性能分析

    Institute of Scientific and Technical Information of China (English)

    孟生云; 杨文革

    2012-01-01

    The introduction of the hybrid DS/FH spread spectrum technology could enhance TTC systems electronic countermeasure capability.The expression of the wideband ambiguity function(WAF) is derived.It is known that,with carrier frequency increase,the difference between wideband and narrowband ambiguity function decrease for weakened signal duration impact on ambiguity function.However,signal duration change should be matched in the receiving signal processing.On the basis of the WAF expression,the performance of waveforms with various spreading gain assignment such as resolution,accuracy,sidelobe suppression and anti-jamming are simulated numerically and analyzed.Simulation results show that DS/FH signals possess almost ideal thumbtack AF plot with certain spreading gain assignment,and better resolution and anti-jamming performances would be obtained with relatively large FH spreading gain.%引入直扩/跳频(DS/FH)混合扩频技术可以增强航天测控系统的电子对抗能力。推导了DS/FH混合扩频信号的宽带模糊函数表达式。通过分析得知,随着载波频率的增加,信号时长的变化对模糊值的影响减弱,宽带和窄带模糊函数间的差异减小,但在接收信号的处理中仍需考虑对信号时长变化的匹配。数值仿真分析了DS/FH信号波形在不同增益分配下的分辨率、精度、旁瓣抑制及抗干扰等性能。结果表明在一定的增益分配下,该波形具有接近理想的图钉型模糊图,适当增加跳频增益可以获得更好的分辨率和抗干扰性能。

  19. Monitoring technique for seepage line of tailings dam

    Institute of Scientific and Technical Information of China (English)

    李夕兵; 蒋卫东

    2003-01-01

    An automatic monitoring technique of the seepage line, including the monitoring design, the automatic monitoring system and the backfill technique of the measuring probe of pore-water pressure, was used in a tailings dam, and a shallow refractive seismic method was investigated for obtaining the seepage line of those areas outside the monitoring zone. The results show that the automatic monitoring has the error within ± 3 % relative to piezometric tube method and improves monitoring efficiency greatly, and the shallow refractive seismic method has the error within ± 10% but expands the area of monitoring. Both of them can be used for a daily measurement in monitoring the seepage line. The result of the automatic monitoring also shows that not only the design of the survey line and the backfill technique of the measuring probe of pore-water pressure are reasonable and economic but also the reliability and safety of the automatic monitoring system are better. Testing result by the shallow refractive seismic method in tailings reveals that the energy excited by hammering iron sheet-pole is strong enough and safe, and that the character of anti-jamming by the detectors with long tailcone is better.

  20. A Real Orthogonal Space-Time Coded UWB Scheme for Wireless Secure Communications

    Directory of Open Access Journals (Sweden)

    Zhang Yanbing

    2009-01-01

    Full Text Available Recent research reveals that information security and information-hiding capabilities can be enhanced by proper exploitation of space-time techniques. Meanwhile, intrinsic properties of ultra-wideband (UWB signals make it an outstanding candidate for secure applications. In this paper, we propose a space-time coding scheme for impulse radio UWB systems. A novel real orthogonal group code is designed for multi-antenna UWB signals to exploit the full spatial diversity gain and achieve the perfect communication secrecy. Its performance in a frequency-selective fading channel is analyzed. The transmission secrecy, including low probability of detection (LPD, low probability of intercept (LPI, and anti-jamming performance, is investigated, and some fundamental tradeoffs between these secrecy metrics are also addressed. A comparison of the proposed scheme with the direct sequence spread spectrum (DSSS technique is carried out, which demonstrates that proper combination of UWB and space-time coding can provide substantial enhancement to wireless secure communications over other concurrent systems.

  1. Models in frequency-hopping-based proactive jamming mitigation for space communication networks

    Science.gov (United States)

    Shen, Dan; Chen, Genshe; Pham, Khanh; Blasch, Erik; Tian, Zhi

    2012-06-01

    In this paper, we consider a cognitive radio based space communication system in a game-theoretical framework, where players dynamically interact through wireless channels to utilize the wideband spectrum for their objectives. The performance indices include data rate, covertness, jamming, and anti-jamming; each of which relate to an effective signal-nose-ratio (SNR). The game players have different intents and asymmetric and hierarchical information about the frequency spectrum which are modeled as three different types of players: primary users, secondary users, and hostile active jammers. We consider the informational asymmetry in two situations: (1) different information sets for friendly users and jammers and (2) even among the friendly sensors; some sensors may only have partial or little information about others due to jammed observations. Such an asymmetric information pattern naturally partitions the sensors into leaders and followers. In our hierarchical anti-jammer approach, a two level approach includes a pursuit-evasion game and a Stackelberg game. At the higher-level, a non-cooperative pursuit-evasion game is constructed to model the interactions between jammer and primary users in the frequency-location domains. At the lower level, primary and secondary users play a dynamic Stackelberg game in the presence of jammers. Theoretical game solutions are provided to demonstrate the proposed proactive jamming mitigation strategy.

  2. [Study on polarization spectral feature of suspended sediment in the water body].

    Science.gov (United States)

    Zhu, Jin; Wang, Xian-Hua; Pan, Bang-Long

    2012-07-01

    Remote sensing of lake water based on water-leaving radiance is to retrieve the concentrations of suspended sediment, phytoplankton and yellow substance which have great impacts on spectrum to assess the water quality. Howerver, because of the complexity of the lake water compositons and the interference between the different components, it is of great difficulty to get accurate results with the reflectance spectrum method developed recently. In the present paper, the authors firstly discussed the reflectance and polarization spectral feature of suspended sediment water body, found out the relations of the reflectance and the degree of polarization of water-leaving radiance and the concentration of suspended sediment at the sensitive bands. The authors also compared the effectiveness of the retrieval approaches based on reflectance and polarization in laboratory water body and Chaohu water body respectively. The results show that in the lake water body where the constituents are very complex, the polarization information has greater capacity of anti-jamming, therefore it will have great potential applictions in lake water quality remote sensing. PMID:23016352

  3. 红外对抗及其半实物仿真试验研究%Research on Infrared Countermeasure and Hardware-in-the-loop Simulation

    Institute of Scientific and Technical Information of China (English)

    陈敏; 李龙

    2013-01-01

      随着红外探测技术的不断发展,红外干扰与抗干扰技术也不断更新、发展。介绍了红外对抗的原理,方法,着重介绍了模拟红外对抗的红外半实物仿真试验,分析了仿真系统中的关键技术及各种可供选择的场景模拟和运动平台特点,最后提出了一种切实可行的红外半实物仿真试验方案。%  With the development of infrared technology, infrared jamming and anti-jamming technologies are constantly updating and developing. The principle of infrared countermeasure method is introduced, with a particular emphasis on infrared hardware-in-the-loop simulation experiment of IR countermeasure. The scene simulation, the motion platform, and key technical characteristics are analyzed. Finally, a viable infrared hardware-in-the-loop method is presented.

  4. A hierarchical model for structure learning based on the physiological characteristics of neurons

    Institute of Scientific and Technical Information of China (English)

    WEI Hui

    2007-01-01

    Almost all applications of Artificial Neural Networks (ANNs) depend mainly on their memory ability.The characteristics of typical ANN models are fixed connections,with evolved weights,globalized representations,and globalized optimizations,all based on a mathematical approach.This makes those models to be deficient in robustness,efficiency of learning,capacity,anti-jamming between training sets,and correlativity of samples,etc.In this paper,we attempt to address these problems by adopting the characteristics of biological neurons in morphology and signal processing.A hierarchical neural network was designed and realized to implement structure learning and representations based on connected structures.The basic characteristics of this model are localized and random connections,field limitations of neuron fan-in and fan-out,dynamic behavior of neurons,and samples represented through different sub-circuits of neurons specialized into different response patterns.At the end of this paper,some important aspects of error correction,capacity,learning efficiency,and soundness of structural representation are analyzed theoretically.This paper has demonstrated the feasibility and advantages of structure learning and representation.This model can serve as a fundamental element of cognitive systems such as perception and associative memory.Key-words structure learning,representation,associative memory,computational neuroscience

  5. Design of Stress-Strain Measuring System for Bulldozing Plate Based on Virtual Instrument Technology

    International Nuclear Information System (INIS)

    Soil is a kind of discrete, multiphase compound that is composed of soil particles, liquid and air. When soil is disturbed by bulldozing plate, the mechanical behavior of the soil will become very complex. Based on the law of action and reaction, the dynamic mechanical behavior of disturbed soil was indirectly analyzed by measuring and studying the forces on the bulldozing plate by soil currently, so a stress-strain virtual measuring system for bulldozing plate, which was designed by the graphical programming language DASYLab, was used to measure the horizontal force Fz acting on the bulldozing plate. In addition, during the course of design, the experimental complexities and the interferential factors influencing on signal logging were analyzed when bulldozing plate worked, so the anti-jamming methods of hardware and software technology were adopted correlatively. In the end, the horizontal force Fz was analyzed with Error Theory, the result shown that the quantificational analysis of Fz were identical to the qualitative results of soil well, and the error of the whole test system is under 5 percent, so the tress-strain virtual measuring system was stable and credible

  6. Coupled Integration of CSAC, MIMU, and GNSS for Improved PNT Performance.

    Science.gov (United States)

    Ma, Lin; You, Zheng; Liu, Tianyi; Shi, Shuai

    2016-01-01

    Positioning, navigation, and timing (PNT) is a strategic key technology widely used in military and civilian applications. Global navigation satellite systems (GNSS) are the most important PNT techniques. However, the vulnerability of GNSS threatens PNT service quality, and integrations with other information are necessary. A chip scale atomic clock (CSAC) provides high-precision frequency and high-accuracy time information in a short time. A micro inertial measurement unit (MIMU) provides a strap-down inertial navigation system (SINS) with rich navigation information, better real-time feed, anti-jamming, and error accumulation. This study explores the coupled integration of CSAC, MIMU, and GNSS to enhance PNT performance. The architecture of coupled integration is designed and degraded when any subsystem fails. A mathematical model for a precise time aiding navigation filter is derived rigorously. The CSAC aids positioning by weighted linear optimization when the visible satellite number is four or larger. By contrast, CSAC converts the GNSS observations to range measurements by "clock coasting" when the visible satellite number is less than four, thereby constraining the error divergence of micro inertial navigation and improving the availability of GNSS signals and the positioning accuracy of the integration. Field vehicle experiments, both in open-sky area and in a harsh environment, show that the integration can improve the positioning probability and accuracy. PMID:27187399

  7. Research on the measurement of belt speed by video in coal mine based on improved template matching algorithm

    Institute of Scientific and Technical Information of China (English)

    ZHU Ai-chun; HUA Wei; WANG Chun; WANG Yong-xing

    2011-01-01

    In order to improve the intelligence of video monitoring system of belt and make up the deficiency of higher failure rate and bad real-time performance in the traditional systems of measurement of belt speed,according to the fact that the light of coal mine is uneven,the strength of light changes greatly,the direction of belt movement is constant,and the position of camera was fixed,various algorithms of speed measurement by video were studied,and algorithm for template matching based on sum of absolute differences(SAD)and correlation coefficient was proposed and improved,besides,the tracking of feature regions was realized.Then,a camera calibration method using the invariance of the cross-ratio was adopted and the real-time measurement of belt speed by the hardware platform based on DM642 was realized.Finally,experiment results show that this method not only has advantages of high precision and strong anti-jamming capability but also can real-time reflect the changes of belt speed,so it has a comprehensive applicability.

  8. Design of Stress-Strain Measuring System for Bulldozing Plate Based on Virtual Instrument Technology

    Science.gov (United States)

    Xu, S. C.; Li, J. Q.; Zhang, R.

    2006-10-01

    Soil is a kind of discrete, multiphase compound that is composed of soil particles, liquid and air. When soil is disturbed by bulldozing plate, the mechanical behavior of the soil will become very complex. Based on the law of action and reaction, the dynamic mechanical behavior of disturbed soil was indirectly analyzed by measuring and studying the forces on the bulldozing plate by soil currently, so a stress-strain virtual measuring system for bulldozing plate, which was designed by the graphical programming language DASYLab, was used to measure the horizontal force Fz acting on the bulldozing plate. In addition, during the course of design, the experimental complexities and the interferential factors influencing on signal logging were analyzed when bulldozing plate worked, so the anti-jamming methods of hardware and software technology were adopted correlatively. In the end, the horizontal force Fz was analyzed with Error Theory, the result shown that the quantificational analysis of Fz were identical to the qualitative results of soil well, and the error of the whole test system is under 5 percent, so the tress-strain virtual measuring system was stable and credible.

  9. CCD video information acquisition technology based on image pattern%基于图象模式的CCD视频信息采集技术

    Institute of Scientific and Technical Information of China (English)

    王汉兵; 黄涛; 雷磊; 周永平; 陈世纯

    2011-01-01

    以某型反坦克导弹CCD观测器测试系统的研制为背景,结合典型CCD观测器的性能及工作原理,对观测器的核心输出信号即视频信息的提取及关键软硬件设计进行了较为深入的研究,运用数字处理和视频采集技术,给出测角精度、抗干扰能力和灵敏度的分析处理方法.系统技术先进,操作界面友好,分析直观,工作可靠,很好地满足使用要求.%This study is one department of CCD observer test system development for a certain type of anti -tank missile. According to the performance and working principle of typical CCD observer, the authors deeply researched the extraction of core output signals, namely video information, and the key software and hardware design of observer. A method for processing and analyzing angle measurement accuracy, anti -jamming capability and sensitivity was provided through digital processing and video capture technology. Such system commendably satisfies the requirements for application with advanced technology, user-friendly interface, intiutive analysis and reliable function.

  10. Multifunction Capacitive Sensor Measuring System Based on USB%USB接口的多功能容栅传感器测量系统

    Institute of Scientific and Technical Information of China (English)

    李孝超; 严高师

    2011-01-01

    According to the principle of capacitive sensors and the C8052F321 MCU with USB module,a measurement system based on USB interface is designed. The system can track the maximum and the minimum counting, hold the display and clear, and uses USB interface to exchange data with the host computer. The system uses LM393 chip to convert the signal level of the sensor to the CMOS level,and also uses opto isolation technology to enhance system's anti-jamming capability.%根据容栅传感器的原理与带USB模块的C8051F321单片机,设计了一套基于USB接口的测量系统。该系统能实现最大数跟踪、最小数跟踪、示值保持和清零等功能,通过USB接口与上位机交换数据。系统中采用LM393芯片将传感器信号电平转换为CMOS电平,采用光耦隔离技术等增强系统的抗干扰能力。

  11. Multifunction Displacement Measurement System Based on Short-range Wireless Technology%基于短距离无线技术的多功能位移测量系统

    Institute of Scientific and Technical Information of China (English)

    李孝超; 严高师

    2012-01-01

    根据容栅传感器的原理和具有高灵敏度的A7102射频芯片加低功耗的STM8L101F3单片机,设计了一套多功能无线位移测量系统.该系统能实现最大数跟踪、最小数跟踪、示值保持和清零等功能.系统中采用专用芯片将传感器信号电平转换为CMOS电平,还采用光耦隔离技术等增强系统的抗干扰能力.%According to the principle of capacitive sensors and the A7102 RF chip with a high sensitivity and the STM8L101F3 MCU with low-power consumption,this paper designed a multifunction wireless measurement system. This system can track the maximum and the minimum, keep count and clear. The system used a special chip to convert the signal level of the sensor to the CMOS level, and it used opto isolation technology to enhance the system's anti-jamming capability.

  12. A Unified Multi-Functional Dynamic Spectrum Access Framework: Tutorial, Theory and Multi-GHz Wideband Testbed

    Directory of Open Access Journals (Sweden)

    Zhe Chen

    2009-08-01

    Full Text Available Dynamic spectrum access is a must-have ingredient for future sensors that are ideally cognitive. The goal of this paper is a tutorial treatment of wideband cognitive radio and radar—a convergence of (1 algorithms survey, (2 hardware platforms survey, (3 challenges for multi-function (radar/communications multi-GHz front end, (4 compressed sensing for multi-GHz waveforms—revolutionary A/D, (5 machine learning for cognitive radio/radar, (6 quickest detection, and (7 overlay/underlay cognitive radio waveforms. One focus of this paper is to address the multi-GHz front end, which is the challenge for the next-generation cognitive sensors. The unifying theme of this paper is to spell out the convergence for cognitive radio, radar, and anti-jamming. Moore’s law drives the system functions into digital parts.From a system viewpoint, this paper gives the first comprehensive treatment for the functions and the challenges of this multi-function (wideband system. This paper brings together the inter-disciplinary knowledge.

  13. Carrier Sense Random Packet CDMA Protocol in Dual-Channel Networks

    Directory of Open Access Journals (Sweden)

    C. Du

    2015-06-01

    Full Text Available Code resource wastage is caused by the reason that many hopping frequency (FH sequences are unused, which occurs under the condition that the number of the actual subnets needed for the tactical network is far smaller than the networking capacity of code division net¬working. Dual-channel network (DCN, consisting of one single control channel and multiple data channels, can solve the code resource wastage effectively. To improve the anti-jamming capability of the control channel of DCN, code division multiple access (CDMA technology was introduced, and a carrier sense random packet (CSRP CDMA protocol based on random packet CDMA (RP-CDMA was proposed. In CSRP-CDMA, we provide a carrier sensing random packet mechanism and a packet-segment acknowledgement policy. Furthermore, an analytical model was developed to evaluate the performance of CSRP-CDMA networks. In this model, the impacts of multi-access interference from both inter-clusters and intra-clusters were analyzed, and the mathematical expressions of packet transmission success probability, normalized network throughput and signal interference to noise ratio, were also derived. Analytical and simulation results demonstrate that the normalized network throughput of CSRP-CDMA outperforms traditional RP-CDMA by 10%, which can guarantee the resource utilization efficiency of the control channel in DCNs.

  14. Research progress in SAW filter banks

    Institute of Scientific and Technical Information of China (English)

    HE Shi-tang

    2005-01-01

    SAW (Surface Acoustic Wave) filter bank is a single input, single or multi-output device consisting of multi-SAW-filters with input interconnection network or switch circuits, and can be divided into two categories: channelizer (multi-output) and switchable (programmable, single output). The former is mainly used in military channelized receiver for spectrum analysis;the latter has wide application in frequency synthesizer and frequency-hopping radar and communication system receiver as anti-jamming filter, and has been widely used in various military electronic equipments ever since the 1970s.Research abroad was done mainly by Americans, few documents on related work done by Japan and Russia are available. Domestic research started in the 1980s, mainly by No. 26 Research Institute, China Electronics Technology Group Co., Institute of Acoustics, Chinese Academy of Sciences, No. 23 and No. 25 Research Institute, China Spaceflight Tech. Group Co. This paper first briefly introduces Chinese and foreign research on SAW filter banks;then discusses research progress in device design, the input interconnection network or switch circuit and miniaturization;and ends in a brief perspective of developing trends in future.

  15. Test results judgment method based on BIT faults

    Institute of Scientific and Technical Information of China (English)

    Wang Gang; Qiu Jing; Liu Guanjun; Lyu Kehong

    2015-01-01

    Built-in-test (BIT) is responsible for equipment fault detection, so the test data correct-ness directly influences diagnosis results. Equipment suffers all kinds of environment stresses, such as temperature, vibration, and electromagnetic stress. As embedded testing facility, BIT also suffers from these stresses and the interferences/faults are caused, so that the test course is influenced, resulting in incredible results. Therefore it is necessary to monitor test data and judge test failures. Stress monitor and BIT self-diagnosis would redound to BIT reliability, but the existing anti-jamming researches are mainly safeguard design and signal process. This paper focuses on test results monitor and BIT equipment (BITE) failure judge, and a series of improved approaches is proposed. Firstly the stress influences on components are illustrated and the effects on the diagnosis results are summarized. Secondly a composite BIT program is proposed with information integra-tion, and a stress monitor program is given. Thirdly, based on the detailed analysis of system faults and forms of BIT results, the test sequence control method is proposed. It assists BITE failure judge and reduces error probability. Finally the validation cases prove that these approaches enhance credibility.

  16. Electromagnetic Compatibility about Backpack Type Inverter & Motor Structure%背包式变频器与电机集成结构的电磁兼容探讨

    Institute of Scientific and Technical Information of China (English)

    秦立新; 刘洋

    2012-01-01

    变频器与电机的集成结构——背包式的电磁兼容问题是个技术问题.由于采用了背包式结构,变频器和电机型式试验将作为一台电机整体来进行考核.变频器的使用,提高了电机系统效率,但是,变频器背包却带来了较为复杂的电磁兼容问题.介绍了背包式变频器+电机的原理和结构,分析了此结构的电磁兼容问题,并提出了系统抗干扰的实际办法.%In the integration structure of the inverter and motor, the electromagnetic compatibility of backpack type is a technical problem. Because of the backpack type structure, type test assessment of motor & inverter will be as a motor overall. Backpack type inverter improves the efficiency of motor system, but brings complex electromagnetic compatibility problems . The principle and structure about backpack type inverter & motor was introduced, the electromagnetic compatibility problems was analyzed, and practical measures of anti-jamming system was put forward.

  17. A Novel Monopulse Angle Estimation Method for Wideband LFM Radars

    Directory of Open Access Journals (Sweden)

    Yi-Xiong Zhang

    2016-06-01

    Full Text Available Traditional monopulse angle estimations are mainly based on phase comparison and amplitude comparison methods, which are commonly adopted in narrowband radars. In modern radar systems, wideband radars are becoming more and more important, while the angle estimation for wideband signals is little studied in previous works. As noise in wideband radars has larger bandwidth than narrowband radars, the challenge lies in the accumulation of energy from the high resolution range profile (HRRP of monopulse. In wideband radars, linear frequency modulated (LFM signals are frequently utilized. In this paper, we investigate the monopulse angle estimation problem for wideband LFM signals. To accumulate the energy of the received echo signals from different scatterers of a target, we propose utilizing a cross-correlation operation, which can achieve a good performance in low signal-to-noise ratio (SNR conditions. In the proposed algorithm, the problem of angle estimation is converted to estimating the frequency of the cross-correlation function (CCF. Experimental results demonstrate the similar performance of the proposed algorithm compared with the traditional amplitude comparison method. It means that the proposed method for angle estimation can be adopted. When adopting the proposed method, future radars may only need wideband signals for both tracking and imaging, which can greatly increase the data rate and strengthen the capability of anti-jamming. More importantly, the estimated angle will not become ambiguous under an arbitrary angle, which can significantly extend the estimated angle range in wideband radars.

  18. High Speed Dim Air Target Detection Using Airborne Radar under Clutter and Jamming Effects

    Directory of Open Access Journals (Sweden)

    A. E. Almslmany

    2015-06-01

    Full Text Available The challenging potential problems associated with using airborne radar in detection of high Speed Maneuvering Dim Target (HSMDT are the highly noise, jamming and clutter effects. The problem is not only how to remove clutter and jamming as well as the range migration and Doppler ambiguity estimation problems due to high relative speed between the targets and airborne radar. Some of the recently published works ignored the range migration problems, while the others ignored the Doppler ambiguity estimation. In this paper a new hybrid technique using Optimum Space Time Adaptive Processing (OSTAP, Second Order Keystone Transform (SOKT, and the Improved Fractional Radon Transform (IFrRT was proposed. The OSTAP was applied as anti-jamming and clutter rejection method, the SOKT corrects the range curvature and part of the range walk, then the IFrRT estimates the target’ radial acceleration and corrects the residual range walk. The simulation demonstrates the validity and effectiveness of the proposed technique, and its advantages over the previous researches by comparing its probability of detection with the traditional methods. The new approach increases the probability of detection, and also overcomes the limitation of Doppler frequency ambiguity.

  19. A Novel Monopulse Angle Estimation Method for Wideband LFM Radars.

    Science.gov (United States)

    Zhang, Yi-Xiong; Liu, Qi-Fan; Hong, Ru-Jia; Pan, Ping-Ping; Deng, Zhen-Miao

    2016-01-01

    Traditional monopulse angle estimations are mainly based on phase comparison and amplitude comparison methods, which are commonly adopted in narrowband radars. In modern radar systems, wideband radars are becoming more and more important, while the angle estimation for wideband signals is little studied in previous works. As noise in wideband radars has larger bandwidth than narrowband radars, the challenge lies in the accumulation of energy from the high resolution range profile (HRRP) of monopulse. In wideband radars, linear frequency modulated (LFM) signals are frequently utilized. In this paper, we investigate the monopulse angle estimation problem for wideband LFM signals. To accumulate the energy of the received echo signals from different scatterers of a target, we propose utilizing a cross-correlation operation, which can achieve a good performance in low signal-to-noise ratio (SNR) conditions. In the proposed algorithm, the problem of angle estimation is converted to estimating the frequency of the cross-correlation function (CCF). Experimental results demonstrate the similar performance of the proposed algorithm compared with the traditional amplitude comparison method. It means that the proposed method for angle estimation can be adopted. When adopting the proposed method, future radars may only need wideband signals for both tracking and imaging, which can greatly increase the data rate and strengthen the capability of anti-jamming. More importantly, the estimated angle will not become ambiguous under an arbitrary angle, which can significantly extend the estimated angle range in wideband radars. PMID:27271629

  20. Bistatic weak target detection method using non-cooperative air surveillance radar

    Institute of Scientific and Technical Information of China (English)

    Zengping Chen

    2015-01-01

    At present, most of the passive radar system re-searches utilize FM radios, TV broadcasts, navigation satel ites, etc. as il uminators. The transmitted signals are not specifical y de-signed radar waveforms. In this work, the frequency agile, phased array air surveil ance radar (ASR) is used as the il uminator of opportunity to detect the weak target. The phased array tech-nology can help realize beam agility to track targets from diffe-rent aspects simultaneously. The frequency agility technology is widely employed in radar system design to increase the ability of anti-jamming and increase the detection probability. While the fre-quency bandwidth of radar signals is usual y wide and the range resolution is high, the range cel migration effect is obvious during the long time integration of non-cooperative bistatic radar. In this context, coherent integration methods are not applicable. In this work, a parametric non-coherent integration algorithm based on task de-interweaving is proposed. Numerical experiments verify that this is effective in weak target detection.

  1. Detection and Cancellation of Jamming Signal Noise Using Digital Filters for Radar Applications

    Directory of Open Access Journals (Sweden)

    Ch. Anoosha

    2013-09-01

    Full Text Available This paper considers the problem of detecting and classifying a radar target signal from a jamming signal produced from a target jammer source. Jamming is intentional emission of radio frequency signals to interfere with the operation of a radar by saturating its receiver with noise or false information. In order to distill the features of radar echo-signal affected by strong jamming noise, the adaptive filters are used to remove the noise and recover the radar echo-signal. An Adaptive filter which has self adjusting characteristics and it adapts automatically to change in its input signal. Adaptive filters are used when there is spectral overlap between the signal and noise. The proposed method uses Wiener filter, Least Mean Squares(LMS algorithm and Recursive Least Mean(RLS algorithm in order to detect the radar echo signal affected by jamming noise and results of all the filters are compared with the Signal-to-noise ratio, range of convergence and number of iterations. The simulation results show that the RLS algorithm is effective for anti-jamming of radar signal

  2. Blocking junctional adhesion molecule C enhances dendritic cell migration and boosts the immune responses against Leishmania major.

    Directory of Open Access Journals (Sweden)

    Romain Ballet

    2014-12-01

    Full Text Available The recruitment of dendritic cells to sites of infections and their migration to lymph nodes is fundamental for antigen processing and presentation to T cells. In the present study, we showed that antibody blockade of junctional adhesion molecule C (JAM-C on endothelial cells removed JAM-C away from junctions and increased vascular permeability after L. major infection. This has multiple consequences on the output of the immune response. In resistant C57BL/6 and susceptible BALB/c mice, we found higher numbers of innate immune cells migrating from blood to the site of infection. The subsequent migration of dendritic cells (DCs from the skin to the draining lymph node was also improved, thereby boosting the induction of the adaptive immune response. In C57BL/6 mice, JAM-C blockade after L. major injection led to an enhanced IFN-γ dominated T helper 1 (Th1 response with reduced skin lesions and parasite burden. Conversely, anti JAM-C treatment increased the IL-4-driven T helper 2 (Th2 response in BALB/c mice with disease exacerbation. Overall, our results show that JAM-C blockade can finely-tune the innate cell migration and accelerate the consequent immune response to L. major without changing the type of the T helper cell response.

  3. Fuzzy clustering of infrared images applied in air leak localization

    Science.gov (United States)

    Ge, Nan; Peng, Guang-zheng; Jiang, Mu-zhou

    2009-07-01

    Most current research into the localization of leaks is focused on leaks of petroleum and natural gas pipelines, while there is very little new work being done on the leakage of vessels. A novel air-leak diagnosis and localization method based on infrared thermography is described in this paper, which is developed in an attempt to overcome the disadvantages of low efficiency and poor anti-jamming ability associated with the traditional approaches to localization of leaks from a vessel. The method achieves leak positioning through a factor θ based kernelized fuzzy clustering segmentation done to weighted differential thermal images of the test objects. The temperature difference factor θ is inventively built as a parameter changed with temperature range of the target region, in order to enhance the robustness and the interference proof ability of the algorithm. Heat transfer simulation with air-leak flow is addressed by the finite element analysis. The experimental results indicate that the method proposed is effective and sensitive. The purpose of air-leak localization has been reached.

  4. ECCM Effectiveness Measure for SAR Noise Jamming%SAR有源压制干扰抑制效果评估方法研究

    Institute of Scientific and Technical Information of China (English)

    于春锐; 张永胜; 董臻; 梁甸农

    2012-01-01

    合成孔径雷达(SAR)是对地观测和军事侦察的重要手段,但SAR非常容易受电子干扰的影响.SAR干扰技术的发展也促进了抗干扰技术的发展,现代SAR系统往往采用多种抗干扰技术.干扰抑制效果的评估是衡量一种抗干扰方法有效性以及SAR系统抗干扰性能的一项综合性指标.本文针对有源压制干扰,将干扰抑制效果评估方法划分为主观评估方法和客观评估方法.对于主观评估方法,引入了图像质量等级改善因子的概念,提出了基于图像质量等级评估标准的主观评估法,该方法可以在一定程度上降低主观评估结果的随机性和主观性.对于客观评估方法,研究了基于回波能量的评估方法和基于图像质量指标的评估方法,给出了具体的评价指标,可以客观、定量的对干扰抑制效果进行评估.最后分别采用点目标和面目标对客观评估方法进行了仿真验证,结果表明了方法的可行性和有效性.%Synthetic aperture radar ( SAR) plays an important role in earth observation and military reconnaissance fields, but the SAR systems are susceptible to electronic counter measures (ECM). The development of SAR ECM also promoted the SAR electronic counter-countermeasures(ECCM) , generally, modern SAR systems typically can use a variety of antijamming technology. ECCM effectiveness measure is a method to verify the effectiveness of an anti-jamming technology as well as to measure the anti-jamming performance of the SAR system. In this paper,the methods for ECCM effectiveness measure were divided into subjective evaluation methods and objective evaluation methods. For the subjective evaluation, the improvement factor of image quality grade was introduced, and an image quality grade evaluation criteria based method was proposed, which could be subjective to reduce the randomness and subjectivity. For the objective evaluation, the methods based on echo and based on image quality index

  5. 促凝剂对乙型肝炎病毒实时荧光定量检测影响的评估%Assessment of coagulant on hepatitis B virus by real-time fluorescent quantitative detection*

    Institute of Scientific and Technical Information of China (English)

    姜立茹; 马莹

    2013-01-01

    目的评估促凝剂对乙型肝炎病毒实时荧光定量检测的影响。方法随机采集2011年10月至2012年3月到西安市中心医院门诊的41例患者每人2管血样,分别为无添加剂普通管和促凝剂管,检测分离血清时间及效果。采用实时荧光定量聚合酶链反应检测乙型肝炎病毒DNA ,结果对数值采用SPSS11.5统计软件进行处理,并对促凝剂管标本进行精密度和抗干扰性能评价。结果促凝剂管分离血清平均时间为(4.73±0.86)min ,普通管为(14.46±2.27)min ,两组数据经配对 t检验,差异有统计学意义(P<0.01);促凝剂管乙型肝炎病毒DNA结果对数平均值为(3.86±2.99),普通管组对数平均值为(3.85±2.96),两组经配对 t检验,差异无统计学意义(P>0.05),促凝剂管具有高精密度和抗干扰性能。结论促凝剂对乙型肝炎病毒实时荧光定量检测结果准确性没有影响,可减少报告周转时间,值得临床推广和应用。%Objective To evaluate effect of the coagulant on hepatitis B virus by real-time fluorescent quantita-tive detection .Methods From October 2011 to March 2012 were randomly collected in Xi'an city central hospital of 41 patients with each of 2 tubes of blood samples .which were without additives common tube and the coagulant tube . To detected the serum separation time and effect ,using real-time fluorescence quantitative PCR for detection of hepa-titis B virus DNA ,logarithmic mean was performed by SPSS11 .5 statistical analysis ,and the coagulant tube speci-mens for precision and anti-jamming performance evaluation .Results Coagulant group separation of serum average time was (4 .73 ± 0 .86)min ,common tube group was (14 .46 ± 2 .27)min ,data from the two groups were paired t test ,the difference was statistically significant (P0 .05) .coagulant tube had the advantages of high precision and anti-jamming performance .Conclusion

  6. 小波滤波与QRS波检测%Wave fiitering and QRS detection.

    Institute of Scientific and Technical Information of China (English)

    杨思军; 郝继飞; 闫文杰; 丁小平

    2011-01-01

    利用双正交样条小波等效滤波器,实现了 ECG 信号的小波分解和重建.分析心电信号奇异点与其小波变换模极大值对的零交叉点的关系,提出了心电信号 QRS 波检测的算法.在检测算法中还使用了一系列策略来提高算法的抗干扰能力和 QPS检测的准确性.经 MIT/BIH 心律失常数据库验证,QRS 波的正确检测率达 99.506%.最后将该算法应用到 Windows Mobile 智能手机上的心电监护系统中,达到令人满意的效果.%ECG signal's decomposer and reconstruction have been achieved by using a biorthogonal filter bank based on quadratic spline wavelet. Analyzing the relationship between the signal singularity and the zero-crossing point of the modulus maximum pair of its wavelet trausform, QRS complexes detected arithmetic is proposed. Some strategies are applied to improve the arithmetic anti-jamming ability against noise and to increase the QRS detection veracity. The correctness of QRS complexes detection rate can be up to 99.506%,which has been validated by MIT/BIH ECG signal database. Finally,this arithmetic is applied to the ECG monitoring system based on the Windows Mobile smart phones and achieves satisfactory results.

  7. 髋关节股骨近端CT序列图像外轮廓提取研究%Extern contour extraction research for proximal femur in CT ;images of hip joint

    Institute of Scientific and Technical Information of China (English)

    罗三定; 刘倩兰; 陈远兵; 邹峥

    2014-01-01

    In order to segment the extern contours of hip joint correctly and effectively, a kind of extraction method for extern contour of proximal femur is presented based on the best segmentation curve. The proposed method can find a closed seg-mentation curve which segments target femur part against remaining femur part by the virtue of frame similarity for bottom up CT image sequences, so as to locate the position of the target femur accurately, and search for the edge point by the vir-tue of the segmentation carve. The result of the experiments show that the proposed method can extract the extern contour of proximal femur from CT images accurately with strong adaptivity and good anti-jamming.%为正确有效地分割出髋关节的外轮廓,提出了一种基于最佳分割线的股骨近端外轮廓的提取方法。该方法利用自底向上CT序列图像的帧间相似性找到一条分割目标股骨与其他骨骼的闭合分割线,从而利用该分割线来精确定位目标骨骼的位置,并搜索边缘点。实验结果表明,该方法能够准确地识别出股骨近端的外轮廓,自适应强,抗干扰性好。

  8. Intelligent Vehicle System Based on Embedded Systems%嵌入式技术的智能车系统设计与实现研究

    Institute of Scientific and Technical Information of China (English)

    任肖丽; 黄婉刁; 卢孙平; 王骥

    2014-01-01

    基于 MC9 S12 XS128的智能车,通过对道路图像进行采集和处理,再利用算法控制策略、PID控制原理和 PWM控制技术对智能车转向和速度进行控制,使小车能够自主行驶,通过使用 CodeWarrior 软件编程和 BDM调试实现小车行驶控制。本文基于 PID算法提出了改进的算法,经实物验证,所设计的智能车系统能有效循迹,保持在道路中间快速行驶,可以实现提前转弯,且系统具有较好的抗干扰能力。%The intelligent vehicle based on MC9S12XS128 collects and processes image information by the camera,and then uses algo-rithm control strategy,PID control principle and PWM control technology to control the steering and speed of intelligent vehicle,so that the car is capable of road self-identification,independent drive,and finally the car driving control using CodeWarrior software program-ming and BDM debugging.In this paper,an improved algorithm based on the PID algorithm is proposed.By physical verification,the design of the intelligent vehicle system can effectively track,keep moving fast in the middle of the road,turn in advance,and the system has better anti-jamming capability.

  9. 循环流化床锅炉主蒸汽压力模型预测控制%Model predictive control based main steam pressure control system for CFB boilers

    Institute of Scientific and Technical Information of China (English)

    钱虹; 杨祖魁; 金蔚霄; 房振鲁

    2015-01-01

    Due to large time delay of the main steam pressure control system in CFB boilers,the convention-al PID and PI control methods are unable to obtain well control effect.Thus,a method based on the model predictive control (MPC)algorithm was proposed.The MPC algorithm was applied in the main steam pres-sure control regulator,and load disturbance simulation test was carried out to further verify the model pre-dictive control result.The simulation results show that,compared with the conventional PID and PI control systems,the MPC algorithm based main steam pressure control system has better stability,adaptability,ro-bustness and stronger anti-jamming performance.%由于循环流化床(CFB)锅炉主蒸汽压力控制系统的大延时性,使得常规 PID,PI 控制方法难以取得较好的调节效果。对此,提出了一种基于模型预测控制(MPC)的主蒸汽压力控制方法,将该算法运用于主蒸汽压力控制系统,并对系统进行负荷扰动仿真试验,以验证控制效果。结果表明,基于 MPC 的主蒸汽压力控制系统稳定性、适应性、鲁棒性和抗干扰能力均优于常规 PID,PI 控制。

  10. Study on the determination of molybdate content in industrial circulating cooling water%工业循环冷却水中钼酸盐含量测定研究

    Institute of Scientific and Technical Information of China (English)

    白莹; 邵宏谦; 杨裴; 李琳

    2012-01-01

    A method for determinating the molybdate content in industrial circulating cooling water,i.e. thiocyanate spectrometry,is introduced. The molybdate is reduced to Mo5+ by adding 6.0 mL of sulfuric acid solution, 1.0 mL of ferrous ammonium sulphate solution, 10.0 mL of ammonium thiocyanate solution and 1.0 mL ascorbic acid solution, and forms orange complex with thiocyanate. The absorbency of the complex is determined at 460 run and the molybdate content is figured out by the calibration curve. This method is scientific and stable,and having strong capacity of anti-jamming. Its determination range is suitable for circulating cooling water.%介绍了一种测定工业循环冷却水中钼酸盐含量的方法——硫氰酸盐分光光度法.在待测水样中加入6.0 mL硫酸溶液,1.0 mL硫酸亚铁铵溶液,10.0 mL硫氰酸铵溶液以及1.0 mL抗坏血酸溶液,此时钼酸盐被还原成Mo5+,并与硫氰酸盐形成橙色络合物,在460m波长处测定该络合物的吸光度并通过标准曲线计算出钼酸盐含量.该方法科学、稳定,抗干扰能力强,测定范围适用于循环冷却水中钼酸盐含量的测定.

  11. 磁悬浮开关磁阻球体电机的数学模型及其仿真%Spherical switched reluctance motor with magnetic levitation

    Institute of Scientific and Technical Information of China (English)

    戴敏; 曾励

    2011-01-01

    针对双绕组无轴承开关磁阻电机的绕组结构复杂、绝缘程度要求高及加工成本高的缺陷,结合悬浮原理和磁阻最小原理,提出一种磁悬浮开关磁阻球体电机.分析了磁悬浮开关磁阻球体电机的基本组成和运行机理,采用磁路分割法对各部分磁路进行推导与计算,建立了球体电机的数学模型.利用Matalab/simunik软件进行仿真,结果表明电机能够实现动子快速稳定悬浮和旋转,并且具有良好的抗干扰性能.%In view of the bearingless switched reluctance motor with double windings, which has a complicated structure, an absolute insulation, and expensive manufacture cost, the paper presents a spherical switched reluctance motor with magnetic levitation on the basis of suspension theory and minimum reluctance principle. It analyses elements and machanism of the spherical switched reluctance motor with magnetic levitation, deduces and calculates the magnetic conduction of the gap by means of the magnetic segmentation. It obtaines a model building of spherical electric machines.With the Matalab/simunik model, simulation results show that the rotor realizes quick stable suspension and rotation, it has excellent anti-jamming performance as well.

  12. A low-temperature bridge-input CMOS circuit for low-impedance detector

    Science.gov (United States)

    Yuan, HongHui; Chen, YongPing

    2014-09-01

    Low-impedance long-wave infrared detectors (the wavelength longer than 10 microns) have very important applications in cryogenic aim detection, super-distance detection, anti-jamming target identify and so on. Therefore the research in the field of infrared detector technology is of importance. At present, no low-impedance photoconductive detectors are integrated with CMOS circuit. To design low-temperature CMOS circuit being fit for low impedance infrared photoconductive detector and realize high performance IR imaging, using differential amplifier with symmetrical positive and negative power is necessary, the low-resist detector is connected between an input and grounding, the corresponding low resistance is connected between another input and grounding, a larger feedback resistor is used between negative input and output, this structure can effectively solve the matching problem of low-impedance and high-impedance CMOS. In addition, the noise voltage from VBIAS terminal can be effectively reduced by increasing the ratio of the bias resistor and the detector resistance. The whole circuit is designed two grade. The first grade is adopted bridge input structure, this structure is fit for low impedance detector. The positive amplifying method is applied in second grade . The first grade feedback resistance is designed 1M ohm, the circuit is supplied by +/-1.5V. The testing showed that the circuit can work well when it connects with low-impedance infrared photoconductive detector at the liquid nitrogen low temperature. The magnification is up to 30000 times, 3dB bandwidth is more than 4kHz, the equivalent input noise is near 1.5 micron volts. This circuit has perfectly solved the matching problem between high impedance CMOS circuit and low impedance detector.

  13. Implementation of Particle Filter Tracking Algorithm Resisting to Laser Speckle Jamming%抗激光散斑干扰的粒子滤波跟踪算法硬件实现

    Institute of Scientific and Technical Information of China (English)

    程玉宝; 蒋斐; 倪家正

    2012-01-01

    针对传统的电视跟踪系统在激光散斑干扰下跟踪效果不佳的问题,对抗干扰性较强的粒子滤波跟踪算法进行了硬件实现并改进.首先基于“DSP+ ARM”技术架构设计了电视跟踪仿真平台;然后对裂变自举粒子滤波跟踪算法进行了研究,并结合仿真平台进行了工程化改进、优化和实现,提高了运算速度,满足了高效性和实时性的跟踪要求.实验结果表明,该仿真平台能够运行改进的裂变自举粒子滤波算法,达到实时稳定的跟踪要求,具备一定的抗激光散斑干扰的能力.%To solve the problem that the traditional TV-guided system may fail to track the object under laser speckle jamming,the particle filter tracking algorithm,which has stronger jamming resisting capability, was implemented and improved. Firstly, a TV-tracking platform was designed by "DSP + ARM" technology framework. Then,the Fission Bootstrap Particle Filtering (FBPF) was studied,improved and implemented on the platform, the operating speed was improved, which could meet the high-efficiency and real-time tracking demands. Simulation experiment result proved that the platform can implement the improved fission bootstrap particle filter algorithm, meet the real-time and stable tracking demand, and have certain anti-jamming capability.

  14. Multi-Channel Two-Photon Coding Design of Network Transmission Key Distribution Scheme%多信道双光子编码网络传输密钥分配方案设计

    Institute of Scientific and Technical Information of China (English)

    王亚子

    2014-01-01

    Noise impact, improved quantum communication to improve the anti-jamming capability and safety, to avoid the random changes in the polarization state of the photon optical birefringence effect caused a new type of quantum key distribution scheme, the program generates two-photon entangled statekey, can be a probability test control information transmission, and able to resist the the collective polarization rotation in optical fiber transmission noise and dependent polarization loss, has obvious advantages in the communication efficiency under the same anti-noise characteristics. Concludes with a discussion of this program channel, the decoder implementation problems described improved program in the prior art under the conditions of the feasibility.%为提高量子网络通信的抗干扰能力和安全性,避免光纤双折射效应引起的光子偏振态的随机改变而产生的噪声影响,改进了量子密钥分配方案,新的方案可生成双光子纠缠态密钥,并可在验证过程中进行概率检验,从而控制信息传输,新方案可抵抗光纤传输中集体偏振噪声和偏振损失的影响,在同样抗噪特性下通信效率得到很大的提升。最后分析了新方案的信道、解码器的实现方法,说明了改进后方案于现有技术条件下具有可行性。

  15. 基于自抗扰控制器的重力稳定平台控制系统研究%Gravity Stabilized Platform Control System Based on Active Disturbance Rejection Controller

    Institute of Scientific and Technical Information of China (English)

    郭斌; 许江宁; 何泓洋; 郭士荦

    2016-01-01

    Gravity stabilized platform is a kind of complex uncertain movement system which is difficult to get accurate models .It can be affected by mechanical resonance ,torque coupling ,load change and electrical parameters fluctuations ,and requires quick response speed ,strong anti-jamming capability ,and high steady state accuracy .However ,the influences and requirements are contradictory .Therefore ,an active disturbance rejection controller based on gravity stabilized platform is designed .The Simulink simulation results show that the controller possesses good response speed ,adaptivity ,fast speed , high steady accuracy ,strong robustness and anti-interference capability and isn't sensitive to the parameter change .%重力稳定平台系统是一类难以获得精确模型的复杂非线性不确定的运动系统,由于存在机械谐振、力矩耦合负载变化及电气参数波动等因素的影响,并且稳定平台系统要求具有响应速度快,抗干扰能力强,稳态精度高等优良特性。但这些性能指标之间是有矛盾的。针对这一问题,设计了基于重力稳定平台控制系统的自抗扰控制器,并进行了 Simulink仿真。仿真结果表明,该系统具有很好的响应特性、自适应性和速度快,具有很高的稳态精度,而且系统对参数变化不敏感,鲁棒性和抗干扰性都很强。

  16. Research on intelligent algorithms DC brushless speed control system cutting machine%应用于裁断机中无刷直流电机调速系统的智能算法研究

    Institute of Scientific and Technical Information of China (English)

    王法龙; 郑明辉

    2015-01-01

    针对常规PI在无刷电机调速中控制精度低及动态性能差,无法满足裁断机对动力辊电机速度控制要求,本文提出了一种自适应模糊PI控制方法。该方法应用于无刷直流电机双闭环控制的速度外环控制,提高了无刷直流电机的控制精度和动态响应性能。通过Matlab进行仿真,仿真结果表明,采用自适应模糊PI控制相对常规PI控制,无刷直流电机的调速系统具有很好的动态和静态性能,快速响应,超调量小,抗干扰能力强,鲁棒性好。%In the conventional PI control of brushless motor speed low precision and dynamic performance is poor, unable to meet the power roller cutting machine for motor speed control requirements, we propose an adaptive fuzzy PI control method. The method is applied to double-loop control of brushless DC motor speed outer control, improved control accuracy and dynamic response performance brushless DC motor. Through Matlab simulation results show that the adaptive fuzzy PI speed control system to control relative to conventional PI control, brushless DC motor has a good dynamic and static performance, fast response, small overshoot, and strong anti-jamming capability, robustness.

  17. Design and Implement of System the Electromagnetic Launcher Based on DSP%基于DSP电磁轨道炮控制系统设计与实现

    Institute of Scientific and Technical Information of China (English)

    牛颖蓓

    2012-01-01

    In order to achieve autocontroL This report designs hardware and software about control system of electromagnetism rail gun with corresponding data analysis during emitting. The system adopts time sequence control mode of synchronization triggering and collects discharging current waves. Then this report analyzes the whole system performance with comparisons between electromagnetism rail guns with different lengths. The result shows that with different charging voltage the electromagnetism rail is longer and the discharging pulse is wider, the system efficiency is better. The system with DSP autocontrol has high response speed, high anti-jamming and high accuracy of test data.%在电磁轨道炮发射过程中,为了实现自动控制并结合相应数据分析电磁发射过程中各系统的运行状态和整体系统性能;从硬件和软件两个部分设计实现了电磁轨道炮控制系统,采用同步触发时序控制方式,进行放电电流波形采集;通过对比轨道炮的不同长度分析整个系统性能;实验结果表明,电磁轨道炮充电电压变化时,电磁轨道越长,放电脉宽增加,系统的整体效率得到提高;采用DSP控制系统对电磁轨道炮进行自动控制,具有反应速度快、抗干扰能力强、试验数据精度高等优点.

  18. Design of Power Conditioning System in Superconducting Magnetic Energy System Based on Voltage Source Converter%基于VSC的超导储能装置中功率调节系统的设计

    Institute of Scientific and Technical Information of China (English)

    张金良; 周博曦; 卞秋野

    2013-01-01

      针对超导储能装置中基于电压源型变流器的功率调节系统,给出了基于电压源型变流器(VSC)和斩波器(Chopper)的超导储能(SMES)装置功率调节系统(PCS)的主电路拓扑结构和使用占空比表达的PCS低频数学模型,提出了使用非线性变换实现状态方程线性化的方法,通过状态方程的线性化实现有功功率、无功功率及直流侧电压解耦控制的系统设计。Matlab/Simulink环境下系统仿真结果表明,设计的PCS系统控制器对阶跃和正弦波功率指令具有很强的跟踪能力,且直流侧电压有很强的抗干扰能力。%Aiming at the power conditioning system (PCS) in the superconducting magnetic energy system (SMES) based on volt-age source converter (VSC), this paper gave the main circuit structure of PCS in the SMES based on the VSC and Chopper, as well as the low-frequency mathematical model of PCS which is expressed in the functions of duty ratio. The non-linear transformation was used to linearize state equations to realize the decoupled control between active power, reactive power and DC voltage. The simulated results in Simulink of Matlab showed that the designed PCS has perfect performance in tracing power orders in the form of step and sine waves with strong anti-jamming ability for voltage at DC side.

  19. 基于噪声卷积的灵巧噪声伪码调相引信干扰%Smart noise j amming based on noise convolution modulation countering pseudo-random code phase modulation fuze

    Institute of Scientific and Technical Information of China (English)

    隋鉴; 李国林; 王凌

    2014-01-01

    Pseudo-random code phase modulation fuze has become the key point of fuze countermeasure study,because of its strong anti-jamming ability.Smart noise jamming based on noise convolution modulation is proposed to counter this fuze.The mechanism of generating smart noise based on convolution modulation is stat-ed,and the output signals of the pseudo-random code phase modulation fuze is analyzed under the smart noise jamming.It is proved theoretically that the smart noise jamming could form deceptive jamming and blanket jam-ming effect on the pseudo-random code phase modulation fuze.Simulations demonstrate that the theoretical analysis is valid and the smart noise jamming is more efficient than the traditional jamming methods.%伪码调相引信的良好抗干扰能力,使其成为引信对抗研究的重点。提出了基于噪声卷积的灵巧噪声对伪码调相引信进行干扰。阐述了灵巧噪声的产生机理,推导了灵巧噪声作用于伪码调相引信时,引信输出信号的形式,理论分析证明了灵巧噪声可以对伪码调相引信形成欺骗干扰和压制干扰效果。仿真验证了理论分析的正确性,与传统干扰相比,灵巧噪声干扰的干扰效率更高。

  20. The design of an ultra-wideband miniaturized GPR antenna%一种超宽带小型化探地雷达天线的设计

    Institute of Scientific and Technical Information of China (English)

    彭宇; 王蕾; 郭福强; 胡通海

    2014-01-01

    通过对蝶形偶极子天线复合加载的方式形成一种小型化的探地雷达天线,多种加载方式的引入不但使天线具有宽频带的性能,而且设计的天线尺寸与理论计算尺寸相比也大大减小。在天线后方引入背腔设计,增加了天线的方向性和抗干扰能力。所设计的天线具有1.5~4 GHz的频带宽度,且天线的方向性良好。设计的天线已成功应用于LTD探地雷达2.2 GHz天线系统和3 GHz的液态危险品检测天线系统中。%A kind of miniaturized GPR antenna was designed through complex loading to the bow-tie dipole. The introduction of multi-ple loading methods not only makes the antenna acquire the performance of broadband but also greatly decreases the size of antenna compared with the theoretical calculation size. By introducing back cavity behind the antenna, the directivity and anti-jamming capabili-ty of the antenna are enhanced. The designed antenna possesses a 1.5 GHz~4 GHz frequency band width and a good direction. The de-signed antenna is successfully applied to the antenna system of 2.2 GHz LTD series of GPR. This designed antenna can be also used in the dangerous liquid goods inspection system of 3 GHz LTD series of GPR.

  1. A Novel Approach to Beam Steering Using Arrays Composed of Multiple Unique Radiating Modes

    Science.gov (United States)

    Labadie, Nathan Richard

    Phased array antennas have found wide application in both radar and wireless communications systems particularly as implementation costs continue to decrease. The primary advantages of electronically scanned arrays are speed of beam scan and versatility of beamforming compared to mechanically scanned fixed beam antennas. These benefits come at the cost of a few well known design issues including element pattern rolloff and mutual coupling between elements. Our primary contribution to the field of research is the demonstration of significant improvement in phased array scan performance using multiple unique radiating modes. In short, orthogonal radiating modes have minimal coupling by definition and can also be generated with reduced rolloff at wide scan angles. In this dissertation, we present a combination of analysis, full-wave electromagnetic simulation and measured data to support our claims. The novel folded ring resonator (FRR) antenna is introduced as a wideband and multi-band element embedded in a grounded dielectric substrate. Multiple radiating modes of a small ground plane excited by a four element FRR array were also investigated. A novel hemispherical null steering antenna composed of two collocated radiating elements, each supporting a unique radiating mode, is presented in the context of an anti-jam GPS receiver application. Both the antenna aperture and active feed network were fabricated and measured showing excellent agreement with analytical and simulated data. The concept of using an antenna supporting multiple radiating modes for beam steering is also explored. A 16 element hybrid linear phased array was fabricated and measured demonstrating significantly improved scan range and scanned gain compared to a conventional phased array. This idea is expanded to 2 dimensional scanning arrays by analysis and simulation of a hybrid phased array composed of novel multiple mode monopole on patch antenna sub-arrays. Finally, we fabricated and

  2. Measurement and Control System for Ratory Balance Equipment in Wind Tunnel Test%风洞旋转天平试验装置测控系统

    Institute of Scientific and Technical Information of China (English)

    宋晋; 孙棣华; 赵敏; 刘赟; 马军

    2016-01-01

    The rotary balance is used for simulating spin state in wind tunnel, and getting aerodynamic force data at the same time. In order to make the measurement and control system have the characteristics of high automation, high precision and strong anti-jamming ability, the paper designs and realizes the system for wind tunnel. It includes 3 subsystems, which are the test management, the data acquisition and the motion control. The test result shows, the system can run automatically under the control of test management subsystem, achieve kinds of motion control and get data in complex electromagnetic environment. The system is simple, stable and reliable. The design idea and the techniques have a certain reference value.%旋转天平是一种用来模拟飞机尾旋并获取气动力的试验装置,为使该装置的测控系统具有自动化程度高、测试精度高和抗干扰能力强的特点,设计并实现了一套应用于风洞旋转天平的测控系统。该系统包括了试验管理、天平数据采集和旋转运动控制3个子系统。测试结果表明:该系统可在试验管理子系统的调度下自动化运行,能够实现试验所需的多种运动控制,并能在复杂电磁环境下完成数据采集。该系统操作简单、稳定可靠,设计思路及所采用的技术具有一定的参考意义。

  3. [Research on lateral shearing interferometer for field monitoring of natural gas pipeline leak].

    Science.gov (United States)

    Zhang, Xue-Feng; Gao, Yu-Bin

    2012-09-01

    Aimed at the mechanical scanning spectroscopy equipment with poor anti-interference and anti-jamming ability, which affects the accuracy of its natural gas pipeline leak detection in the wild, a new type of lateral shearing interferometer system was designed. The system uses a beam splitter to get optical path difference by a mechanical scanning part, and it cancel the introduction of external vibration interference through the linkage between the two beam splitterw. The interference intensity of interference fringes produced was calculated, and analysis of a rotating beam splitter corresponds to the angle of the optical path difference function, solving for the maximum angle of the forward rotation and reverse rotation, which is the maximum optical path range. Experiments using the gas tank deflated simulated natural gas pipeline leak process, in the interference conditions, and the test data of the type WQF530 spectrometer and the new type of lateral shearing interferometer system were comparedt. The experimental results show that the relative error of both systems is about 1% in indoor conditions without interference. However, in interference environment, the error of WQF530 type spectrometer becomes larger, more than 10%, but the error of the new type of lateral shearing interferometer system is still below 5%. The detection accuracy of the type WQF530 spectrometer decreased significantly due to the environment. Therefore, the seismic design of the system can effectively offset power deviation and half-width increases of center wavelength caused by external interference, and compared to conventional mechanical scanning interferometer devices the new system is more suitable for field detection. PMID:23240445

  4. On the Control Scheme of Each Digital and Analog Quantity of the Reactor%反应器各数字量与模拟量的控制方案研究

    Institute of Scientific and Technical Information of China (English)

    唐令怡

    2015-01-01

    With the continuous development of science and technology, the demands of industrial production process for automation are higher and higher. In order to achieve the optimal control effect and control accuracy, this paper uses Siemens PCS7, WinCC software and PLC400 controller to design the control scheme of the reactor. Through analyzing the different control requirements and characteristics of the different control variables, the most suitable control scheme is gotten. Then, the proportional control, cascade control, PID control and fuzzy PID control are adopted to realize the effective control of the temperature, liquid level, reactant concentration, pressure and product concentration for the reactor. At the same time, the good anti-jamming ability of the system is ensured. Finally, the configuration of communications, hardware and monitoring picture is implemented by Siemens PCS7 and WinCC software, and a set of complete, available plan of control system is accomplished.%随科技的不断发展,工业生产过程对自动化的需求越来越高。为了达到最优的控制效果与控制精度,本文采用基于西门子PCS7、WinCC软件和PLC400控制器的对反应器的控制方案设计。控制方案的确定是通过对不同控制变量不同的控制需求和控制特点的分析,得到最适合的控制方案。最终采用了比例控制、串级控制、PID控制和模糊PID控制,实现了对反应器的温度、液面、反应物浓度、压力以及产物浓度的有效控制。同时,也保证了系统具有良好的抗干扰能力。最后,利用西门子PCS7和WinCC软件,实现了通讯、硬件和监控画面的组态,最终成为一套完整、可用的控制系统方案。

  5. Imitation modeling of ice dams (case study of Tom’ River, Western Siberia

    Directory of Open Access Journals (Sweden)

    V. A. Zemtsov

    2014-01-01

    Full Text Available The factors of ice jam formations in the lower flow of the Tom River (Siberia are investigated. A length of the main channel under investigation is about 120 km. Approaches to solution of the problem of the jam formation control and, as a consequence, the jam induced floods are considered on the basis of the imitative computer modeling of stream dynamics and ice jams. The simulation makes it possible to analyze different scenarios of initial forcing and to predict reactions of the river bed system to the effects. On the basis of 1D models developed in the HEC-RAS 4.0 modeling system for the Tom River at the city of Tomsk we investigated a possibility of the ice jam localization, probability of which at different parts of river flow varies in time according to change of the river water discharge, stream hydraulics, and ice cover thickness. The 2D hydrodynamic model of the Tom River channel system in the SMS 9.2 modeling system has been developed. It allows simulating effects of ice jams located in different sections of the river flow on the run-off redistribution between the main channel and other river branches. It makes possible to estimate hazards and risks of ice jam floods and probable effects of ice jams on formation of the river channel system. As a result it becomes possible to regulate the safe spring ice transit through populated areas.Analysis of factors of the ice jam formations has demonstrated that due to increasing anthropogenic influence changes of hydro-meteorological and geomorphologic conditions lead to more frequent occurrence of jam floods for the last 25 years as compared to previous 40-year period. The imitative computer models are proposed to be used for planning anti-jam measures since they make possible to create a whole system of the channel structure, a relief of channel and floodplain, a flow velocity field including dangerous hydrologic processes. Similar system would allow predicting both consequences of local

  6. A Calculation Method of Burst Height of Ballistic Missile Based on Radar Seeker%一种基于雷达导引头的弹道导弹爆高解算方法

    Institute of Scientific and Technical Information of China (English)

    郑宗贵; 王继平; 林红斌; 解静

    2014-01-01

    目前弹道导弹主要通过无线电引信测高来进行战斗部爆高控制,但弹头的再入环境对无线电引信测高装置的要求非常高,且引信存在着易被干扰的问题。为此,该文针对采用雷达景象匹配末制导的弹道导弹,提出一种基于雷达导引头的弹道导弹爆高控制方法,通过雷达导引头测高数据与惯性导航数据的融合处理,实时计算弹头飞行高程,来实现爆高控制,既保证了精度,又增强了抗干扰能力。仿真算例证明了该方法的有效性和爆高解算精度。%At present the height of the warhead of ballistic missile is measured by the radio fuze for the burst height control of the warhead, but the reentry environment of the warhead has very high requirement for the measure set of the radio fuze, and there exists the issue of the radio fuze to be jammed. In the paper, for the ballistic missile adopting the radar scene matching terminal guidance, a calculation method of burst height of ballistic missile based on radar seeker is put forward, by fusing the height measure data of the scene matching radar seeker and the inertial navigation data, the height of the warhead is calculated in real time to realize the burst height control, which ensures the precision and improves anti-jamming capability. The validity of the method and the calculation precision of the burst height are proved by simulation and calculation.

  7. 一种陀螺稳定平台自适应模糊-PID复合控制方法%Adaptive fuzzy-PID hybrid control method of gyro stabilized platform

    Institute of Scientific and Technical Information of China (English)

    朱倚娴; 陆源; 许江宁; 程向红

    2014-01-01

    机械摩擦、器件工作饱和区等不确定因素会导致陀螺稳定平台系统参数的波动和非线性特性,为解决非线性因素对稳定平台控制系统性能的影响,提出了一种自适应模糊-PID复合控制方法。引入自适应因子δ实现模糊控制和PID控制的复合,误差较大时增强模糊控制的作用以加快系统响应,误差较小时增强PID控制的作用以实现无静差调节。采用自调整量化因子ker(er)、kec(ec)实现基本论域的在线调整,提高了模糊控制器的灵敏度。仿真结果表明,在干扰冲击和短时常值干扰情况下,自适应模糊-PID复合控制与常规模糊控制相比,抗干扰能力显著增强,平台稳定精度提高0.4'左右。%System parameters of gyro stabilized platform are unpredictable because of the uncertainty factors such as mechanical friction, the saturation characteristic of the driver module, etc. To suppress the error caused by the nonlinear characteristics, an adaptive fuzzy-PID hybrid control method is proposed. The adaptive factorδis set up to combine fuzzy control and PID control. When the large attitude error of the platform is detected, the effect of fuzzy control is enhanced to decrease the system response time. And the conventional PID control effect is enhanced to eliminate the static error when the attitude error is small. Self-adjusting quantitative factors ker(er) andkec(ec) are proposed to adjust the basic domain of the fuzzy controller online, which improves the sensitivity of the control loop. The simulation results show that, in both cases of pulse and step interference,theadaptive fuzzy-PID hybrid control can improve the accuracy of platform attitude about 0.4 arc min and enhance its capability of anti-jamming compared to ordinary fuzzy control.

  8. Study on Polarization Spectral Feature of Suspended Sediment in the Water Body%水体悬浮泥沙的偏振光谱特性研究

    Institute of Scientific and Technical Information of China (English)

    朱进; 王先华; 潘邦龙

    2012-01-01

    Remote sensing of lake water based on water-leaving radiance is to retrieve the concentrations of suspended sediment, phytoplankton and yellow substance which have great impacts on spectrum to assess the water quality. Howerver, because of the complexity of the lake water compositons and the interference between the different components, it is of great difficulty to get accurate results with the reflectance spectrum method developed recently. In the present paper, the authors firstly discussed the reflectance and polarization spectral feature of suspended sediment water body, found out the relations of the reflectance and the degree of polarization of water-leaving radiance and the concentration of suspended sediment at the sensitive bands. The authors also compared the effectiveness of the retrieval approaches based on reflectance and polarization in laboratory water body and Chaohu water body respectively. The results show that in the lake water body where the constituents are very complex, the polarization information has greater capacity of anti-jamming, therefore it will have great potential applictions in lake water quality remote sensing.%基于离水辐射的湖泊水体遥感通过反演与光谱关系密切的悬浮泥沙、浮游植物和黄色物质等要素的浓度来实现对水质状况的评估,然而由于湖泊水体的复杂性以及不同要素间的相互干扰,现有的基于反射率光谱的分析方法难以准确反演这些要素.从悬浮泥沙水体离水辐射的反射率、偏振光谱特性出发,给出敏感波段处悬浮泥沙浓度与反射率、偏振度之间的关系,比对了基于反射率以及基于偏振度的两种反演方法在实验室水体、巢湖水体中的应用效果.研究结果表明,在湖泊复杂水体条件下,水体的偏振信息具有比反射率更加良好的抗干扰能力,显示偏振度信息在湖泊水质遥感上存在着重要的应用潜力.

  9. Application of Metamaterials to the Optimization of Smart Antenna Systems

    Science.gov (United States)

    Allen, Jeffery Wayne

    Recent developments in engineered electromagnetic materials called metamaterials have opened the door to a whole new class of devices and improved performance in existing systems using electromagnetic properties that are beyond those found in nature. These materials can be designed to have spatially varying anisotropic electromagnetic properties which include positive and negative permeability and permittivity values. The objective of this research was to explore how these newly available degrees of freedom in material parameters can be exploited to improve the performance of smart antenna systems. In this dissertation, we examined adaptive null/beam forming phased array systems in the presence of metamaterial superstrates. While these systems have been studied extensively from a system engineering point-of-view, understanding the system from a material engineering prospective will help define the role that these new materials can play in these systems and how they maybe designed to enhance the overall system performance. One specific area further explored is how to steer the available performance of these systems, preferentially to regions of the scan space where interferers/jammers are most likely to occur, thus improving the system's anti-jamming or interference mitigation capabilities. New performance gains can also be suggested by including the behavior of sources and accompanying material properties in the transformations optics methodology to modify space through material design. This can be achieved using source transformations. Chapter 1 introduces the basic theory of phased array systems and radomes, background of previous work carried out, Controlled Radiation Pattern Antennas, Global Position Systems and a short overview of transformation optics and metamaterials. In Chapter 2, we present analytical, ray tracing and full-wave electromagnetic simulation models to analyze the effect of a quasi-optical element on the array performance. We use these models

  10. 水下重力异常相关极值匹配算法%Correlative Extremum Matching Algorithm Using Underwater Gravity Anomalies

    Institute of Scientific and Technical Information of China (English)

    李姗姗; 吴晓平; 马彪

    2011-01-01

    Gravity-aided inertial navigation is a technique that makes use of gravity to correct inertial navigation error of underwater vehicles.Matching algorithm is vital in the process of gravity-aided inertial navigation.An object function model of differential descending weight-correlation was put forward based on the principle of mean square deviation.Because of the influence of random errors,there are multi-available positions determined by the object function model which are around the real position with different probabilities.Then,a probabilistic data association filter(PDAF) algorithm was proposed.Navigation position determined by PDAF is much closer to the actual one than that chosen by the nearest neighbor method,the reliability and the anti-jamming of the algorithm are improved.Then,the effect of the serial sampling intervals on the matching precision was discussed.Through simulations in the experimental area,the results showed that navigation errors were corrected effectively with proper sampling intervals and sampling lengths based on the algorithm.%重力辅助惯性导航是利用地球物理特征信息——重力来修正水下潜器惯性导航误差,其关键技术是匹配算法。基于平均平方差最小准则构造差分降权相关目标函数模型,针对受干扰误差随机影响,基于目标函数模型搜索得到的多个有效位置,均有可能以不同概率密度源于正确位置这一问题,提出概率数据关联滤波重力匹配算法,与最近邻法相比,该算法确定的航迹更接近于真实位置,提高算法的可靠性与抗干扰性;分析探讨序列采样间隔对匹配精度的影响。通过试验区仿真匹配,结果表明,当选择适当的采样间隔与采样长度,该算法能有效修正导航误差。

  11. 基于改进Otsu的室外道路实时检测与跟踪算法%Real-time Detection and Tracking of Road Information for Outdoor Vision-based Robot Based on Improved Otsu

    Institute of Scientific and Technical Information of China (English)

    陆培源; 王建中; 罗涛

    2011-01-01

    The detection and tracking of road infornmtion, are the basis and prerequisite of environmental exploration anti autonomous navigation ],y mobile robot. In view of the complexity of the ouldoor working environment of the robot and the variety of the outdoor illumination conditions, a suitable and novel way of real-time detection and tracking for outdoor robot is presented. First, the video images obtained from CCD camera are preprocessed. Then the Region of Interest (ROI) is extracted and transformed into the HSV color space. The edge information of the road image is obtained from the ROI by using the improved Otsu algorithm. With the anti-jamming ability of the Hough transform, the regiom where robot can pass through is shown. Finally the weighted Mahalanobis distance discrimination method is used to track the passing area. Experiment results show that this algorithm enjoys a good performance in the detection and tracking of road information in outdoor environment in real-lime.%室外道路检测与跟踪是移动机器人完成室外环境探索和自主导航的基础和前提.针对室外机器人工作环境复杂、光照多变等特点,提出了一种适用于室外道路实时检测与跟踪的算法.首先将CCD摄像头获得的画面通过预处理,提取视频画面的感兴趣区域(ROI)并转化为HSV颜色空间下的图像,然后通过改进的自适应阈值分割法(Otsu)获得道路图像的边缘信息,采用抗干扰能力较强的霍夫(Hough)变换得出画面中的可通行区域,最后采用加权马氏距离判别法跟踪可通行区域.实验表明,该算法在室外环境下具有较好的道路识别跟踪能力和实时性.

  12. Study of Fuzzy Adaptive PID Control of Brushless DC Motor%无刷直流电机模糊自适应PID控制的研究

    Institute of Scientific and Technical Information of China (English)

    潘晓磊; 赵川; 吕海立

    2016-01-01

    为了提高无刷直流电机控制系统的动、静态性能,将模糊控制结合PID控制算法应用到无刷直流电机速度控制系统中。在分析了无刷直流电机速度控制系统的基础上,利用PSIM与MATLAB/Simulink共同建立了无刷直流电动机模糊自适应PID控制的仿真模型,充分发挥了PSIM和MATLAB/Simulink各自在仿真方面的优势,简化了建立仿真模型的过程。仿真结果表明,采用模糊PID集成控制算法能够使无刷直流电机速度控制系统具有更快的响应速度和更强的抗干扰能力,对无刷直流电机控制系统的设计具有一定的指导意义。%In order to improve the static and dynamic performance of brushless DC motor control system, fuzzy control combined with PID control algorithm is applied to the brushless DC motor speed control system, the integration of fuzzy PID control algorithm. On the analysis of the brushless dc motor speed control system, using the MATLAB/Simulink to establish brushless DC motor speed control system simulation model. Among them, the control system of brushless DC motor drive model and control algorithm were established in PSIM and MATLAB/Simulink environment, give full play to their advantages, the PSIM and MATLAB simplifies the process of establishing simulation model. The simulation results show that the integration of fuzzy PID control algorithm can make the brushless DC motor speed control system has better dynamic and static performance and strong anti-jamming capability, the design of brushless DC motor control system has a certain guiding significance.

  13. Research progress of automatic navigation technology for orchard mobile robot%移动机器人自动导航技术研究进展

    Institute of Scientific and Technical Information of China (English)

    蒋浩然; 陈军; 王虎; 雷王利; 袁池

    2011-01-01

    针对目前果园移动机器人自动导航技术研究现状,综合分析现有的有关文献,依据环境感知方式的不同,分别讨论了以激光、视觉、机械、电磁、GPS、超声波为感知系统的导航方法的研究进展,分析了现有几种导航方法在精度、实时性、抗干扰能力及系统适应性等方面的优缺点,认为多传感器融合技术可为果园移动机器人的导航提供更高的精度和稳定性。在此基础上,提出了未来果园移动机器人自动导航技术的发展趋势,即多传感器融合技术是果园移动机器人感知环境的主要手段,满足果园移动机器人精度和稳定性要求的导航系统将是今后研究的重点。%The existing related literatures were analyzed based on the current research progress of the orchard mobile robot's automatic navigation technology.According to the different environmental perception methods,the current research status of the navigation methods with perception systems based on laser,vision,machinery,electromagnetism,ultrasonic and GPS were discussed respectively;the advantages and disadvantages of each method in terms of navigation accuracy,real time,anti-jamming capability and the flexibility of the system were also discussed.Then we believe that the multi-sensor fusion technology could provide higher precision and stability for the orchard mobile robots' automatic navigation.On that basis,this paper proposed the development tendency of automatic navigation technology for orchard mobile robot in the future,multi-sensor fusion technology would become the main method of the environment perception for orchard mobile robot.Therefore,the development of the navigation system with required accuracy and stability for the orchard mobile robot would be the emphasis of the future research.

  14. 基于多水质参数融合的锅炉连排复合控制%Compound ControI of BoiIer Continuous BIowdown Based on MuItipIe Water QuaIity Parameters

    Institute of Scientific and Technical Information of China (English)

    王恭; 周晓东; 张腾宇; 赵鑫岩; 王冰礁; 曹生现

    2015-01-01

    Aiming at the difficulty in rational control over the continuous blowdown’s flow of the power plant boiler,the feed forward-feedback control system based on the boiler water’s quality parameters was designed. In its feed forward control,the system makes use of the data fusion algorithm to associate the water quality pa-rameters (pH,conductivity,phosphate ions,silica dioxide)with the continuous sewage flux so as to eliminate the influence of both multivariable and large time delay;in its feedback control,the self-tuning PID control employed can improve the system’s anti-jamming capability and tackle time variation.The simulation results show that the system overshoot can be controlled at 10.5% and the adjusting time can be shortened by nearly 79s in normal operating condition so as to improve the system’s dynamic and static traceability.%针对电厂锅炉连续排污过程中连排流量难以合理控制的特点,设计了基于炉水多水质参数的前馈-反馈控制系统。该系统在前馈环节利用数据融合算法,将炉水水质参数(pH 值、电导率、磷酸根离子、二氧化硅)与连排流量进行关联,以克服多变量及大迟延等特点的影响;反馈环节利用模糊自整定PID 控制,提升系统的抗干扰能力,解决时变性问题。控制系统仿真结果表明:在机组正常运行条件下,该系统可将系统超调量控制在10.5%,调节时间缩短近79s,提升了系统的动静态跟踪能力。

  15. Temperature field reconstruction based on Gaussian radial basis function with subarea optimization%基于高斯径向基的子区域优化温度场重建算法

    Institute of Scientific and Technical Information of China (English)

    柳丹; 石为人; 熊庆宇; 石欣

    2015-01-01

    In the application environment where measuring the temperature in the process of industrial heating,the reconstruc-tion algorithm is the key to realize the measurement of temperature field by using ultrasonic.In order to solve the problem,this paper developed a reconstruction optimization algorithm without changing the number of effective ultrasonic wave.It used the perfect function approximation ability of Gaussian radial basis function to implement the mapping relations between the sound wave propagation velocity and the temperature distribution,then reconstructed the measured temperature field through the ma-trix singular value decomposition.The algorithm had reconstructed four kinds of typical model of temperature field:unimodal skewed,unimodal symmetric,bimodal deflection and bimodal symmetrical under different Gaussian noise interference in the simulation experiments.The simulation results have proved that the algorithm has the advantages of high reconstruction preci-sion,strong anti-jamming capability and fast response speed.%在采用超声波进行工业加热过程中的温度场测量时,重建算法是实现被测温度场重建的关键。针对这一问题,提出一种基于高斯径向基函数的子区域优化温度场重建算法,不改变有效声线数,细化子区域,运用高斯径向基函数,逼近超声波传播速度与温度分布的映射关系,通过矩阵奇异值分解重建被测温度场。针对单峰偏斜/对称、双峰偏斜/对称四种典型模型温度场,在不同高斯噪声干扰下进行温度场重建仿真实验,结果表明:该算法重建精度高、抗干扰能力强、响应速度快。

  16. Measurement Method for Leakage Current of Insulator String Applying LED Optical Fiber Sensor%采用LED光纤传感器的绝缘子串泄漏电流测量方法

    Institute of Scientific and Technical Information of China (English)

    姚陈果; 王建; 冉启华; 李成祥; 米彦

    2012-01-01

    Measuring the leakage current of insulator strings is currently one of the principal means to monitor the contamination level of transmission lines insulator surface;however,due to the complex environment of transmission lines,a large amount of electromagnetic interference will produce much noise at the time of collecting leakage current.Therefore,in order to improve the anti-jamming and accuracy when sensors were used to measure insulator leakage current,an optical fiber sensor was employed to measure leakage current of the insulator strings,in which light emitting diode(LED) was used to detect the current signal as the photoelectric conversion and light signal stability.Taking three-piece XP-160 insulator strings as examples when ρESDD was 0.05~0.2 mg/cm2 and humidity was 85%,we increased the voltage gradually to obtain the leakage current.Results reveal that the optical fiber sensor can achieve selective measurement of leakage current,the positive half cycle or negative half cycle,and the full cycle current can be monitored after differential circuit is improved.Its zero-extinct period is less than 1 ms and response time is limited in 0.1 ms,and its sensitivity reaches 40 V/A.The pertinence coefficients of linear fitting are all higher than 99.94%,and its frequency response is 1~10 kHz,which can meet the basic requirements of the leakage current measurement.%测量绝缘子串的泄漏电流是目前监测输电线路绝缘子串表面污秽状态的主要手段之一,然而由于输电线路环境的复杂性,常常会伴生出大量的电磁干扰,会在泄漏电流的采集源头产生噪声从而导致采集失真。为提高传感器测量绝缘子泄漏电流的抗干扰能力和准确度,采用廉价稳定的光学器件—发光二极管(light emitting diode,LED)设计并制作了1套光纤传感器装置,利用光电转换和光信号的稳定性,以3片XP-160绝缘子串为试验对象,取盐密为0.05~0.2mg/cm2,

  17. Study on APD real time compensation methods of laser Detection system

    International Nuclear Information System (INIS)

    With the monochromatic and the directional capability of the laser, laser detection system is confidential in anti-jamming. Detection accuracy is improved significantly as the result of laser's good orientation ability. Sensitivity is enhanced as laser's high-brightness characteristic. With the development of laser technology and laser devices, laser detections are developed both in civilian and military areas. In the military field, laser detection system has been widely applied in various types of tactical missiles, the technique is more mature. Because photo detectors receive the backscattering echo signal of target in laser detection system, they are required sensitive enough to weak signal. With APD's salient features of high sensitivity, rapid response speed, high response frequency and low noise equivalent power, etc.; PIN is replaced by APD to improve sensitivity of laser detection system in recent years. The signal magnification is inadequate in laser detection system, the detector output is usually amplified by multistage amplifiers. And then the system noise includes detector noise and latter amplifiers noise. With its high internal gain, APD becomes the primary noise source of receiving system. This point can be attested by analyzing the transfer function of laser detection system receiver. To ensure the system detecting ability, APD noise must be mitigated as low as possible. According to a large number of experiments, the power signal-to-noise (SNR) and the best multiplication factor of APD are mostly affected by background radiation and temperature. In order to make APD operate at state of the best multiplication factor, the optimum bias must be selected due to the actual operating circumstance. Therefore, APD realtime compensation must be adopted. The existing APD compensation includes the constant false alarm rate compensation, the noise compensation and the temperature compensation. The features of these compensations are obtained by analyzing

  18. Spherical Reluctance Driving Joint with Magnetic Levitation Modeling and Inverse System Decoupling Control%磁悬浮球形磁阻主动关节的建模与逆系统解耦控制

    Institute of Scientific and Technical Information of China (English)

    曾励; 王军; 徐媛媛

    2011-01-01

    active joint system dynamics model and inverse model. The inverse system model is as a decoupling controller, decoupling the prototype system and get pseudo-linear system. The systems controlled by the pseudo-linear state feedback closed-loop, and its simulation study. Simulation results show that the system has good dynamic response and robust anti-jamming features.

  19. Algorithm Design of Trust Aware Recommender Based on Network Dynamic Interference Monitoring%网络动态干扰监控的信任感知推荐算法设计

    Institute of Scientific and Technical Information of China (English)

    张远红; 苗放

    2014-01-01

    网络用户信任感知推荐的准确性设计是提高用户间的社交网络辅助信息信任度的重要依据。传统的网络用户信任感知推荐算法采用的是基于社交网络服务和用户评分的推荐系统,主观性较大,协同过滤效果不好。提出一种基于网络动态干扰监控的信任感知推荐算法设计新方法,设计自适应神经模糊系统网络动态干扰监测算法,构建基于向量空间模型的信任度评价指标体系结构,通过调整网络拓扑权重向量设置信任度周期响应加权变量自适应函数,有效降低迭代算法的运算成本,避免了自适应神经模糊系统网络动态干扰监测加权权重成固化状态,提高抗干扰性能。实验结果表明,算法能使社交网络感知推荐模型的预测误差减少,推荐可靠性优于传统方法。%The accuracy design of network user trust aware recommender is key to improve social network auxiliary informa-tion between the user trust degree. The network user perceived trust traditional recommendation algorithm is used in the recommendation system, social network services and user ratings based on subjectivity, collaborative filtering effect is not good. A new method of algorithm design of recommendation trust is propsoed based on aware network dynamic interference monitoring and adaptive neural fuzzy dynamic interference, the design of monitoring system network construction algorithm, vector space model of trust evaluation index system based on trust, set the periodic response variable weighted adaptive function to adjust the network topology by weight, reduce the iterative algorithm cost, it avoids the adaptive neural fuzzy net-work dynamic interference monitoring weight into curing condition, the anti jamming capability is improved. The experi-mental results show that it can reduce the prediction error, and make social network aware recommendation model is superi-or to the traditional method, the

  20. 痕量N2O气体检测系统的设计与实现%Design and implementation of trace N2O detection system

    Institute of Scientific and Technical Information of China (English)

    郑守国; 李淼; 张健; 张浩东; 胡泽林

    2012-01-01

    A measurement system based on the spectral absorption was established to measure the N2O concentration accurately. First, the relationship of the second-harmonic, the first-harmonic with N2O gas concentration was demonstrated in theory. Then, a N2O detection system for trace concentration was designed based on a Distribute Feedback Laser(DFB). By using the light modulation and lock-in amplifier technologies, weak gas concentration signals in the strong clutter background were analyzed. Finally, the detection performance, anti-jamming capability and the repeatability of test results were verified through experiments. Test results indicate that the system can offer the measuring range from 0 to 1 % , detection limit of 5. 0×10-5 ,and the relative detection error of 0. 11 %. Furthermore, the linear equation is Y=192. 699 09X-0. 006 24, the linearity is 0. 998 07,and the relative standard deviation is 0. 137%. It also proves that the CO2, O2, water vapor, et al. Have no effect on the experimental results. By changing the centre wavelength of the laser,the system can be used in the detection of other greenhouse gases, such as CO2 and CH4.%建立了基于光谱吸收技术的检测系统,用于快速、准确地测量N2O气体浓度.首先,从理论上证明了二次谐波、一次谐波与N2O气体浓度之间的关系;然后,设计了痕量N2O气体浓度检测系统,利用光源调制、锁相放大等技术,实现了强杂波背景下气体浓度弱信号的解析;最后,实验测试了系统的检测性能、抗干扰能力及检测结果的可重复性.测试结果表明,系统能够在0~1%有效检测N2O气体浓度,检测下限为5.0×10-5,相对检测误差为0.11%,检测结果线性方程为Y=192.699 09X-0.00624,线性度为0.99807.多次检测实验表明,系统相对标准偏差为0.137%,CO2、O2、水蒸气等常见气体对检测结果无影响.改变激光器的中心波长,该方法亦可用于CO2,CH4等其它温室气体的检测.

  1. Research on Lateral Shearing Interferometer for Field Monitoring of Natural Gas Pipeline Leak%新式横向剪切干涉系统对天然气管道泄漏野外监测的研究

    Institute of Scientific and Technical Information of China (English)

    张学锋; 高玉斌

    2012-01-01

    Aimed at the mechanical scanning spectroscopy equipment with poor anti-interference and anti-jamming ability, which affects the accuracy of its natural gas pipeline leak detection in the wild, a new type of lateral shearing interferometer system was designed The system uses a beam splitter to get optical path difference by a mechanical scanning part, and it cancel the introduction of external vibration interference through the linkage between the two beam splitterw. The interference intensity of interference fringes produced was calculated, and analysis of a rotating beam splitter corresponds to the angle of the optical path difference function, solving for the maximum angle of the forward rotation and reverse rotation, which is the maximum optical path range. Experiments using the gas tank deflated simulated natural gas pipeline leak process, in the interference conditions, and the test data of the type WQF530 spectrometer and the new type of lateral shearing interferometer system were comparedt The experimental results show that the relative error of both systems is about 1 % in indoor conditions without interference. However, in interference environment, the error of WQF530 type spectrometer becomes larger, more than 10%, but the error of the new type of lateral shearing interferometer system is still below 5%. The detection accuracy of the type WQF530 spectrometer decreased significantly due to the environment. Therefore, the seismic design of the system can effectively offset power deviation and half-width increases of center wavelength caused by external interference, and compared to conventional mechanical scanning interferometer devices the new system is more suitable for field detection.%针对机械扫描式光谱分析设备抗震、抗干扰能力差等问题影响其在野外检测天然气管道泄露的精确度,设计了一种新式的抗震型横向剪切干涉系统.将分束镜作为机械扫描部分产生光程差,通过两个分束镜之间

  2. 3D numerical simulation of the flow field with push-pull hoods containing barriers between them%罩间存在障碍物的吹吸罩流场三维数值模拟

    Institute of Scientific and Technical Information of China (English)

    胡鸿; 易灿南; 廖可兵

    2013-01-01

    为了使吹吸罩达到对污染物的最佳控制,以某企业电镀生产线上行车行进过程中由于镀件表面黏附高浓度槽液而造成室内环境污染为实物模型,建立吹吸罩口间存在障碍物的三维数学模型,利用Fluent计算动力学软件对不同吹风口风速和吸风口风速下的排风罩流场进行数值模拟,经比较确定最佳联合速度,并将模拟结果与经典吹吸速度分布图及试验条件下所测得的污染气体质量分数进行对比分析.结果表明,所建立数学模型是合理的,所确定的最佳效果时的相关参数与经典理论基本一致,可用于工程实际.%This paper attempts to proposo a 3D numerical simulation model of the flow field with push-pull hoods containing barriers between them in hoping to solve the problem of the dispersion of contaminants.As is known,the dispersion of contaminants in different sections of an apparatus can be controlled effectively via a pull-push hood powered by a jet flow.Actually,such device has already been widely used in places where contaminants are serious but can not be eliminated.The said push-pullhoods are usually armed with the following features:minute air volume,perfect pollution control,powerful anti-jam behavior,free from the impact of the process operations.Although no barriers were considered in the former design between the push hood and pull hood in the regular production process according to the processing demands,we still feel it necessary to stress the demand for them,for it is necessary to choose the best velocity of push hood and pull hood to control the containments.Based on the above starting point,we have chosen the computational fluid dynamics (CFD) model to solve the problem.First of all,we have taken the contaminants accumulated in the painted work-pieces with very harmful content adhered in them as a physical model,while assuming that geometrical models are set by the GAMBIT code.Along with it,let the appropriate