Aiming at applications as a projectile-borne video reconnaissance system, the overall design and prototype in principle of a mortar video reconnaissance system bomb were developed. Mortar launched test results show th...Aiming at applications as a projectile-borne video reconnaissance system, the overall design and prototype in principle of a mortar video reconnaissance system bomb were developed. Mortar launched test results show that the initial integrated system was capable of transmitting images through tens of kilometers with the image resolution identifying effectively tactical targets such as roads, hills, caverns, trees and rivers. The projectile-borne video reconnaissance system is able to meet the needs of tactical target identification and battle damage assessment for tactical operations. The study will provide significant technological support for further independent development.展开更多
瞬时测频(instantaneous frequency measurement,IFM)接收机是电子侦察中非常重要的测频资源,其结构简单、灵敏度高、侦察频带宽、分辨率高,可以快速测定被测信号的频率,在现代电子战中得到广泛应用。基于IFM微波鉴相器在某一瞬间只能...瞬时测频(instantaneous frequency measurement,IFM)接收机是电子侦察中非常重要的测频资源,其结构简单、灵敏度高、侦察频带宽、分辨率高,可以快速测定被测信号的频率,在现代电子战中得到广泛应用。基于IFM微波鉴相器在某一瞬间只能响应一个信号的特性,结合IFM工作原理,研究了一种新的(超过2个信号)对IFM干扰策略,并分析了干扰机理,通过模拟仿真对IFM的干扰效果进行了评估。仿真结果表明:多信号交叠可以对IFM系统产生明显的干扰效果,可以使得其无法测得正确频率,并错误地输出同时到达信号指示。展开更多
低截获概率(low probability of intercept,LPI)雷达已成为新时代雷达装备中关键的技术体制或工作模式,针对LPI雷达信号调制识别及参数估计方法的研究是当前雷达对抗侦察领域的热点。首先,分析了几种典型LPI雷达信号的脉内特征,梳理了LP...低截获概率(low probability of intercept,LPI)雷达已成为新时代雷达装备中关键的技术体制或工作模式,针对LPI雷达信号调制识别及参数估计方法的研究是当前雷达对抗侦察领域的热点。首先,分析了几种典型LPI雷达信号的脉内特征,梳理了LPI雷达信号调制识别及参数估计的传统和主流方法,并说明其原理、优缺点和研究现状。最后,总结了现有LPI雷达信号调制识别及参数估计方法尚存的问题,并指出其未来发展趋势,旨在为今后的研究提供参考。展开更多
In order to solve the problem of carrier frequency blind estimation of PSK signals in electronic reconnaissance, a new estimation method was proposed. The phase shift keying（PSK） signal was divided into several over...In order to solve the problem of carrier frequency blind estimation of PSK signals in electronic reconnaissance, a new estimation method was proposed. The phase shift keying（PSK） signal was divided into several overlapping intervals which had equal length, and the spectrum concentration measures of every interval were extracted by the FFT. And then, using the grid-density clustering, the spectrum concentration measures were classified into two categories, the narrowband spectrum interval and the wideband spectrum interval. The narrowband spectrum interval was regarded as the characteristic class. The spectrums of the characteristic class were accumulated to estimate the carrier frequency of PSK signal. The proposed method had avoided the non linear operation in the traditional PSK signal carrier frequency estimation algorithm. Thus, the signal to noise ratio （SNR） threshold was remarkably decreased. Moreover, the proposed method did not need the prior knowledge of the signal, which was suitable to the electronic reconnaissance occasion. Experimental results had verified the validity of the proposed estimation method in low SNR.展开更多
This paper introduces a new theory and algorithm that can be used in blind detection of the carrier wave signal and the pseudo-random sequence of the direct sequence spread spectrum （DS/SS） signal with negative SNR....This paper introduces a new theory and algorithm that can be used in blind detection of the carrier wave signal and the pseudo-random sequence of the direct sequence spread spectrum （DS/SS） signal with negative SNR. First, without any a priori knowledge of the DS/SS signal, the carrier wave signal can be detected from DS/SS signal with negative SNR by using stochastic differential equations and energy detection method. Based on this, the pseudo-random sequence can also be blindly detected in DS/SS signal with negative SNR by reducing noise of the nonlinear signal and the algorithm of wavelet multiscale decomposition algorithm. Finally, the computer simulation shows that we can detect the carrier wave signal with SNR=-27 dB and the pseudo-random sequence under error code ratio 10^-4with SNR =-10 dB.展开更多
对移动通信终端进行侦察与管控是维护正常通信秩序和电磁空间安全的应有之义。通信系统的行为模式是其重要的特征之一,传统的仅限于信号参数获取的侦察方法无法对移动通信系统的行为模式进行精准分析。针对这一问题,以终端与基站交互过...对移动通信终端进行侦察与管控是维护正常通信秩序和电磁空间安全的应有之义。通信系统的行为模式是其重要的特征之一,传统的仅限于信号参数获取的侦察方法无法对移动通信系统的行为模式进行精准分析。针对这一问题,以终端与基站交互过程中寻呼(Paging)信号与接入(Access)信号为突破口,充分利用该类信号特有的时频特征和明文传输特点,在对其进行有效截获的基础上,经过解调、解扰、解码得到其携带的信息比特。通过对信息比特实施解析,获得交互信令的含义,完成对移动通信终端行为模式的综合分析,揭示了寻呼与接入信号之间通信信息交互的时序逻辑关系,为信息对抗中的灵巧干扰提供了时间与信息字段上的侦察引导,是后续灵巧干扰的基础与前提。最后利用通信侦察接收机对第五代移动通信(5th Generation mobile communication,5G)信号进行实地侦收与分析,实验结果验证了所提方法的正确性与有效性,为移动通信终端的精准侦察与管控奠定了技术基础。展开更多
Airborne passive electronic reconnaissance equipment has developed rapidly during recent years.However,because of its expensive and unavailable military features,the simulation realization of these equipment needs to ...Airborne passive electronic reconnaissance equipment has developed rapidly during recent years.However,because of its expensive and unavailable military features,the simulation realization of these equipment needs to be solved.And the smaller the simulation particle is,the better the simulation system will be.In this study,a signal-level airborne electronic reconnaissance simulation system was built.Mathematical model and simulation realization of each part are introduced in this study.Focusing on the shortness of traditional signal sorting methods,we creatively proposed a presorting method based on the Euclidean distance inside signal flows.Simulation results show that the presorting method based on Euclidean distance successfully reduced the pressure on main sorting and appeared good for signal sorting.Simulation test results of each model built in this study are also shown in the study.This study provides a new thought on the realization of airborne electronic reconnaissance equipment and benefits the development of electronic countermeasure.展开更多
Most blind source separation algorithms are only applicable to real signals,while in communication reconnaissance processed signals are complex.To solve this problem,a blind source separation algorithm for communicati...Most blind source separation algorithms are only applicable to real signals,while in communication reconnaissance processed signals are complex.To solve this problem,a blind source separation algorithm for communication complex signals is deduced,which is obtained by adopting the Kullback-Leibler divergence to measure the signals’independence.On the other hand,the performance of natural gradient is better than that of stochastic gradient,thus the natural gradient of the cost function is used to optimize the algorithm.According to the conclusion that the signal’s mixing matrix after whitening is orthogonal,we deduce the iterative algorithm by constraining the separating matrix to an orthogonal matrix.Simulation results show that this algorithm can efficiently separate the source signals even in noise circumstances.展开更多
文摘Aiming at applications as a projectile-borne video reconnaissance system, the overall design and prototype in principle of a mortar video reconnaissance system bomb were developed. Mortar launched test results show that the initial integrated system was capable of transmitting images through tens of kilometers with the image resolution identifying effectively tactical targets such as roads, hills, caverns, trees and rivers. The projectile-borne video reconnaissance system is able to meet the needs of tactical target identification and battle damage assessment for tactical operations. The study will provide significant technological support for further independent development.
文摘瞬时测频(instantaneous frequency measurement,IFM)接收机是电子侦察中非常重要的测频资源,其结构简单、灵敏度高、侦察频带宽、分辨率高,可以快速测定被测信号的频率,在现代电子战中得到广泛应用。基于IFM微波鉴相器在某一瞬间只能响应一个信号的特性,结合IFM工作原理,研究了一种新的(超过2个信号)对IFM干扰策略,并分析了干扰机理,通过模拟仿真对IFM的干扰效果进行了评估。仿真结果表明:多信号交叠可以对IFM系统产生明显的干扰效果,可以使得其无法测得正确频率,并错误地输出同时到达信号指示。
文摘低截获概率(low probability of intercept,LPI)雷达已成为新时代雷达装备中关键的技术体制或工作模式,针对LPI雷达信号调制识别及参数估计方法的研究是当前雷达对抗侦察领域的热点。首先,分析了几种典型LPI雷达信号的脉内特征,梳理了LPI雷达信号调制识别及参数估计的传统和主流方法,并说明其原理、优缺点和研究现状。最后,总结了现有LPI雷达信号调制识别及参数估计方法尚存的问题,并指出其未来发展趋势,旨在为今后的研究提供参考。
文摘In order to solve the problem of carrier frequency blind estimation of PSK signals in electronic reconnaissance, a new estimation method was proposed. The phase shift keying（PSK） signal was divided into several overlapping intervals which had equal length, and the spectrum concentration measures of every interval were extracted by the FFT. And then, using the grid-density clustering, the spectrum concentration measures were classified into two categories, the narrowband spectrum interval and the wideband spectrum interval. The narrowband spectrum interval was regarded as the characteristic class. The spectrums of the characteristic class were accumulated to estimate the carrier frequency of PSK signal. The proposed method had avoided the non linear operation in the traditional PSK signal carrier frequency estimation algorithm. Thus, the signal to noise ratio （SNR） threshold was remarkably decreased. Moreover, the proposed method did not need the prior knowledge of the signal, which was suitable to the electronic reconnaissance occasion. Experimental results had verified the validity of the proposed estimation method in low SNR.
基金the National Defence Key Foundation of China (Grant No. 614144)
文摘This paper introduces a new theory and algorithm that can be used in blind detection of the carrier wave signal and the pseudo-random sequence of the direct sequence spread spectrum （DS/SS） signal with negative SNR. First, without any a priori knowledge of the DS/SS signal, the carrier wave signal can be detected from DS/SS signal with negative SNR by using stochastic differential equations and energy detection method. Based on this, the pseudo-random sequence can also be blindly detected in DS/SS signal with negative SNR by reducing noise of the nonlinear signal and the algorithm of wavelet multiscale decomposition algorithm. Finally, the computer simulation shows that we can detect the carrier wave signal with SNR=-27 dB and the pseudo-random sequence under error code ratio 10^-4with SNR =-10 dB.
文摘对移动通信终端进行侦察与管控是维护正常通信秩序和电磁空间安全的应有之义。通信系统的行为模式是其重要的特征之一,传统的仅限于信号参数获取的侦察方法无法对移动通信系统的行为模式进行精准分析。针对这一问题,以终端与基站交互过程中寻呼(Paging)信号与接入(Access)信号为突破口,充分利用该类信号特有的时频特征和明文传输特点,在对其进行有效截获的基础上,经过解调、解扰、解码得到其携带的信息比特。通过对信息比特实施解析,获得交互信令的含义,完成对移动通信终端行为模式的综合分析,揭示了寻呼与接入信号之间通信信息交互的时序逻辑关系,为信息对抗中的灵巧干扰提供了时间与信息字段上的侦察引导,是后续灵巧干扰的基础与前提。最后利用通信侦察接收机对第五代移动通信(5th Generation mobile communication,5G)信号进行实地侦收与分析,实验结果验证了所提方法的正确性与有效性,为移动通信终端的精准侦察与管控奠定了技术基础。
文摘Airborne passive electronic reconnaissance equipment has developed rapidly during recent years.However,because of its expensive and unavailable military features,the simulation realization of these equipment needs to be solved.And the smaller the simulation particle is,the better the simulation system will be.In this study,a signal-level airborne electronic reconnaissance simulation system was built.Mathematical model and simulation realization of each part are introduced in this study.Focusing on the shortness of traditional signal sorting methods,we creatively proposed a presorting method based on the Euclidean distance inside signal flows.Simulation results show that the presorting method based on Euclidean distance successfully reduced the pressure on main sorting and appeared good for signal sorting.Simulation test results of each model built in this study are also shown in the study.This study provides a new thought on the realization of airborne electronic reconnaissance equipment and benefits the development of electronic countermeasure.
基金supported by the National Natural Science Foundation of China (Grant No.60672038).
文摘Most blind source separation algorithms are only applicable to real signals,while in communication reconnaissance processed signals are complex.To solve this problem,a blind source separation algorithm for communication complex signals is deduced,which is obtained by adopting the Kullback-Leibler divergence to measure the signals’independence.On the other hand,the performance of natural gradient is better than that of stochastic gradient,thus the natural gradient of the cost function is used to optimize the algorithm.According to the conclusion that the signal’s mixing matrix after whitening is orthogonal,we deduce the iterative algorithm by constraining the separating matrix to an orthogonal matrix.Simulation results show that this algorithm can efficiently separate the source signals even in noise circumstances.
