基于Jamming转变理论的沥青路面车辙演化机制

沥青路面宏观车辙其实质是混合料细观结构演变的结果,为了深入理解路面车辙流变行为的发展过程,基于颗粒物质Jamming理论开展了沥青混合料车辙演化机制研究。采用图像处理技术构建了沥青混合料细观结构模型,基于时-温等效原理开展了车辙仿真测试,分析了车辙变形过程中混合料宏细观结构的变化特征,探究了沥青路面Unjamming转变行为的影响规律与车辙演化机制。结果表明:Jamming理论可以很好地解释沥青路面的车辙演变全过程,车辙深度与沥青混合料颗粒的堵塞程度密切相关;随着加载时间和作用荷载的增加,混合料Jamming堵塞程度增大,车辙深度和面积分数也逐渐增加,并最终趋于稳定,颗粒体系Jammed态的转变受到了沥青砂浆和集料骨架共同作用的影响;随着测试温度升高,试件内部颗粒位移和位移差增大,混合料Jamming堵塞程度降低。沥青路面颗粒体系由稳定的Jammed态转变为不稳定的Unjammed态,是诱导路面车辙和泛油病害发生的内因,研究结果实现了Jamming理论在非晶体系中的应用,为深入理解沥青混合料的车辙演变行为提供了一种新的研究思路。

A target parameter estimation method via atom-reconstruction in radar mainlobe jamming

Mainlobe jamming(MLJ)brings a big challenge for radar target detection,tracking,and identification.The suppression of MLJ is a hard task and an open problem in the electronic counter-counter measures(ECCM)field.Target parameters and target direction estimation is difficult in radar MLJ.A target parameter estimation method via atom-reconstruction in radar MLJ is proposed in this paper.The proposed method can suppress the MLJ and simultaneously provide high estimation accuracy of target range and angle.Precisely,the eigen-projection matrix processing(EMP)algorithm is adopted to suppress the MLJ,and the target range is estimated effectively through the beamforming and pulse compression.Then the target angle can be effectively estimated by the atom-reconstruction method.Without any prior knowledge,the MLJ can be canceled,and the angle estimation accuracy is well preserved.Furthermore,the proposed method does not have strict requirement for radar array construction,and it can be applied for linear array and planar array.Moreover,the proposed method can effectively estimate the target azimuth and elevation simultaneously when the target azimuth(or elevation)equals to the jamming azimuth(or elevation),because the MLJ is suppressed in spatial plane dimension.

Jamming Assisted Covert Wireless Communication in Multi-Channel Systems

This paper investigates the jammerassisted multi-channel covert wireless communication(CWC)by exploiting the randomness of sub-channel selection to confuse the warden.In particular,we propose two sub-channel selection transmission schemes,named random sub-channel selection(RSS)scheme and maximum sub-channel selection(MSS)scheme,to enhance communication covertness.For each proposed scheme,we first derive closed-form expressions of the transmission outage probability(TOP),the average effective rate,and the minimum average detection error probability(DEP).Then,the average effective covert rate(ECR)is maximized by jointly optimizing the transmit power at the transmitter and the number of sub-channels.Numerical results show that there is an optimal value of the number of sub-channels that maximizes the average ECR.We also find that to achieve the maximum average ECR,a larger number of subchannels are needed facing a stricter covertness constraint.

An angular blinking jamming method based on electronically controlled corner reflectors

Passive jamming is believed to have very good potential in countermeasure community.In this paper,a passive angular blinking jamming method based on electronically controlled corner reflectors is proposed.The amplitude of the incident wave can be modulated by switching the corner reflector between the penetration state and the reflection state,and the ensemble of multiple corner reflectors with towing rope can result in complex angle decoying effects.Dependency of the decoying effect on corner reflectors’radar cross section and positions are analyzed and simulated.Results show that the angle measured by a monopulse radar can be significantly interfered by this method while the automatic tracking is employed.

Optimization of jamming formation of USV offboard active decoy clusters based on an improved PSO algorithm

Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and deployment.To improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is proposed.The formation of the cluster determines the effectiveness of jamming.First,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is proposed.Then,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is designed.Finally,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific scenarios.The results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO algorithm.Compared with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources.

Intelligent recognition and information extraction of radar complex jamming based on time-frequency features

In modern war,radar countermeasure is becoming increasingly fierce,and the enemy jamming time and pattern are changing more randomly.It is challenging for the radar to efficiently identify jamming and obtain precise parameter information,particularly in low signal-to-noise ratio(SNR)situations.In this paper,an approach to intelligent recognition and complex jamming parameter estimate based on joint time-frequency distribution features is proposed to address this challenging issue.Firstly,a joint algorithm based on YOLOv5 convolutional neural networks(CNNs)is proposed,which is used to achieve the jamming signal classification and preliminary parameter estimation.Furthermore,an accurate jamming key parameters estimation algorithm is constructed by comprehensively utilizing chi-square statistical test,feature region search,position regression,spectrum interpolation,etc.,which realizes the accurate estimation of jamming carrier frequency,relative delay,Doppler frequency shift,and other parameters.Finally,the approach has improved performance for complex jamming recognition and parameter estimation under low SNR,and the recognition rate can reach 98%under−15 dB SNR,according to simulation and real data verification results.

无线传感器网络中基于几何覆盖的Jamming攻击定位算法

提出一种基于几何覆盖理论的Jamming攻击定位(GCL,geometry-covering based localization)算法。GCL算法利用计算几何中的凸壳理论,特别是最小包容圆方法,对Jamming攻击者进行定位。理论证明了该算法的正确性和较低的时间复杂度(O(nlogn));模拟实验表明,该算法在攻击者攻击范围、网络节点密度以及攻击者位置等度量值变化的情况下,比已有算法具有更好的定位准确度。

OWE-SOJ技术及核迁移试验在香菇交配型因子鉴定中的应用

由于没有明确的形态差异 ,香菇的 3种不亲和交配反应即A =B =,A =B≠和A≠B =难以互相区别。本研究将OWE SOJ技术及核迁移试验用于香菇的交配型分析。结果表明 ,应用OWE SOJ技术 ,可以观察到 3种不同的菌落形态 :由A≠B≠配对形成的具锁状联合的绒毛状菌落 ,由A≠B =配对形成的无锁状联合的栅栏型菌落及由A =B =或A =B≠配对形成的无锁状联合的绒毛状菌落。通过一个附加的常规交配试验 ,A =B =和A=B≠反应易于互相区别开来。核迁移试验表明 ,核迁移出现于A =B≠反应中而不出现于A≠B =反应中。这一结果与OWE SOJ试验的结果是一致的。因此 ,在常规交配型分析的基础上 ,应用OWE SOJ技术及核迁移试验以准确地鉴定样本中所有单核体的交配型因子是可行的。

SOJ干扰条件下雷达网目标跟踪条件CRLB

针对雷达检测概率评估雷达网抗干扰效能方法的局限性,通过对雷达天线和检测概率模型的分析,利用单雷达检测/漏检事件,推导了干扰环境下雷达网的条件CRLB,给出了干扰条件下目标跟踪误差所能达到的一个下界,从而提出了组网雷达基于条件CRLB的效能评估方法,同时从理论上证明了雷达组网的优越性。实验仿真结果表明,SOJ干扰下,利用CRLB可以很明显地证明雷达网融合跟踪比单部雷达性能要好,能比较准确地评估干扰环境下雷达网的性能,因此所述方法具有一定的实际工程意义。

Sinusoidal FM Fuze's Channel Leak and Its Jamming Mechanism

Aim To get the theory base of designing FM fuze's jamming signal, its jamming mechanism was studied. Methods A sinusoidal FM fuze was analyzed in time domain and frequency domain and the concept of channel leak was presented. Results It was proved that information channel leak exists in FM fuze because of the nonlinear property of the mixer. The jamming signal was designed based on the channel leak and the jamming mechanism was analyzed in detail. Conclusion This kind of jamming signal can jam the sinusoidal FM fuzes effectively just depending on the jamming signal's feature itself. It's different from the traditional jamming way of simulating echo. Though the sinusoidal FM fuze was just analyzed, the principle is applicable to all FM fuzes. At the same time, it may be used as the reference for FM radar and communication countermeasures.

OWE-SOJ技术在鉴定香菇交配反应中的应用(英文)

在香菇中 ,由于没有明确的形态差别 ,3种不亲和交配反应 ,即A =B =,A =B≠andA≠B =无法彼此区别。本研究将一种称为OWE -SOJ的新技术应用于香菇单孢分离物的对峙培养。结果表明 ,A≠B≠形成具有锁状联合的绒毛状菌落 ,A≠B =形成没有锁状联合的栅栏型菌落。A =B =和A =B≠都形成无锁状联合的绒毛状菌落 ,但通过一个附加的常规交配试验 ,二者易于相互区别。因此 ,在通常的交配试验基础上 ,应用OWE -SOJ技术准确鉴定 4种不同的交配反应是可行的。

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

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 carded 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 Rician channel and full-band jamming, and 6 dB higher under the condition of Rician channel environment and partial-band jamming.

SOJ与虚假目标复合干扰下目标跟踪技术

在远距离支援干扰下,由于目标检测概率降低,雷达容易出现检测不到目标真实回波的现象,如果此时再施放虚假目标干扰,由于虚假目标回波比目标回波幅度强,雷达更容易误将虚假目标干扰回波当成真实目标的回波。针对上述特点,提出了采用卡方检验,SNR检验鉴别虚假目标,采用集中式雷达网数据处理方法对目标进行跟踪。仿真实验表明,此种方法降低了虚假目标的误鉴别概率,同时也可以较好地实现了干扰下目标的跟踪,具有一定的实际工程意义。

SOJ对无线电指令制导系统性能的影响与对策研究

无线电指令制导是世界上中低空近程地空导弹武器系统中采用最多的制导体制,SOJ是电子战主要的电子攻击方式之一。文中在分析SOJ对无线电指令制导导弹武器系统中各子系统影响的基础上,着重分析了SOJ对目标探测与指示雷达探测性能和制导雷达测角误差的影响,并以外军专用电子战飞机装备的战术干扰系统与低空近程地空导弹武器系统为例进行了定量研究,在此基础上提出了改进措施,为提高无线电指令制导系统的作战性能指明了方向。

SOJ干扰下雷达网检测性能分析

通过建立SOJ干扰时雷达的检测概率分布模型,研究了雷达网在秩K准则和Neym an-Pearson准则时检测概率分布,仿真了不同准则时雷达网的检测概率分布图,分析比较了以上2种融合准则的融合性能。通过仿真发现,雷达网检测概率分布图克服了传统方法利用单个空间位置检测概率描述雷达网性能的局限性,并且为干扰下雷达网融合准则的选取提供了一个更全面、更直观的参考。

利用OWE-SOJ技术鉴定香菇单核体重组型交配型的研究

本研究探讨了利用 OWE-SOQD技术对香菇 (L etinula edodesa)单核体重组型交配型的鉴定。结果表明 ,利用OU VE-SOJ技术能够准确地鉴定出香菇单核体重组型交配型 A x By和 Ay Bx。

SOJ与RGPO复合干扰下目标跟踪技术

SOJ干扰下目标检测概率降低,容易出现检测不到目标真实回波,如果此时再施放RGPO干扰,由于RGPO回波比目标回波幅度强,雷达更容易误将RGPO干扰回波当成真实目标的回波。针对上述特点,提出了采用检测门限自适应与卡方检验相结合的方法实现了对RGPO的鉴别,同时采用多假设跟踪实现了此种复合干扰下的目标跟踪方法。仿真实验表明,此方法具有较高的RGPO鉴别概率同时也可以较好地实现干扰下目标的跟踪,具有一定的实际工程意义。

Cross-eye gain distribution of multiple-element retrodirective cross-eye jamming

The total cross-eye gain of multiple-element retrodirective cross-eye jamming(MRCJ) in the presence of the platform skin return is a distribution rather than a constant value, due to the random variation in the phase of the skin return. Although the median value of the total cross-eye gain distribution had been analyzed in previous studies, the extreme values providing useful indications of the upper and lower bounds of the total cross-eye gain have not been analyzed until now. In this paper, the cumulative distribution function and the extreme values of the total cross-eye gain of MRCJ are derived. The angular error induced in threat monopulse radar as a figure of merit is used to analyze the performance of MRCJ system. Simulation results demonstrate the variation of the angular error and discuss the proper value of jamming-to-signal ratio(JSR) making the MRCJ system more effective in consideration of the whole distribution of the total cross-eye gain.

Deceptive jamming suppression in multistatic radar based on coherent clustering

This paper proposes a suppression method of the deceptive false target(FT) produced by digital radio frequency memory(DRFM) in a multistatic radar system. The simulated deceptive false targets from DRFM cannot be easily discriminated and suppressed with traditional radar systems. Therefore, multistatic radar has attracted considerable interest as it provides improved performance against deception jamming due to several separated receivers. This paper first investigates the received signal model in the presence of multiple false targets in all receivers of the multistatic radar. Then, obtain the propagation time delays of the false targets based on the cross-correlation test of the received signals in different receivers. In doing so, local-density-based spatial clustering of applications with noise(LDBSCAN) is proposed to discriminate the FTs from the physical targets(PTs) after compensating the FTs time delays, where the FTs are approximately coincident with one position, while PTs possess small dispersion.Numerical simulations are carried out to demonstrate the feasibility and validness of the proposed method.

A jamming method against bistatic SAR based on modulation theory

This paper focuses on the jamming problem of bistatic synthetic aperture radar (BiSAR), and a jamming method against BiSAR based on modulation theory is proposed. The proposed jamming method modulates the BiSAR signal with the cosinusoidal phase to generate multi-false targets in range, and further rotates the jammer to generate multi-false targets in azimuth. The range multi-false targets and azimuth multi-false targets form the two-dimensional cover jamming or deception jamming, which can protect the important targets efficiently. The number of false targets, the interval of false targets, and the jamming square can be adjusted flexibly by setting different range jamming parameters and azimuth jamming parameters. The jamming performance and the choosing criteria of jamming parameters are also discussed. Finally, the simulated data verify the effectiveness of the jamming method.