针对侦察干扰一体化系统面向无人平台小型化载荷应用的场景,提出一种基于射频片上系统(radio frequency system on chip,RFSoC)的宽带侦察干扰一体化、小型化系统的设计与实现方法。重点攻克并行实时大带宽侦察干扰技术以及小型化、大...针对侦察干扰一体化系统面向无人平台小型化载荷应用的场景,提出一种基于射频片上系统(radio frequency system on chip,RFSoC)的宽带侦察干扰一体化、小型化系统的设计与实现方法。重点攻克并行实时大带宽侦察干扰技术以及小型化、大带宽侦察干扰一体化软硬件系统构建,并改善和差波束比相测角算法在宽带测角时的测角精度以及间歇采样转发干扰算法的欺骗干扰效果。最后,基于该软硬件系统完成侦察干扰算法实现,验证系统具有优越的侦察定位精度与干扰性能。展开更多
Amorphous systems undergo the jamming transition when the density increases, temperature drops, or external shear stress decreases, as described by the jamming phase diagram which was proposed to unify different proce...Amorphous systems undergo the jamming transition when the density increases, temperature drops, or external shear stress decreases, as described by the jamming phase diagram which was proposed to unify different processes such as the glass transition, random close packing, and yielding under shear stress. At zero temperature and shear stress, the jamming transition occurs at a critical density at Point J. In this paper, we review recent studies of the material properties of marginally jammed solids and the glassy dynamics in the vicinity of Point J. As the only singular point in the jamming phase diagram, Point J exhibits special criticality in both mechanical and vibrational quantities. Dynamics approaching the glass transition in the vicinity of Point J show critical scalings, suggesting that the molecular glass transition and the colloidal glass transition are equivalent in the hard sphere limit. All these studies shed light on the long-standing puzzles of the glass transition arid unusual properties of amorphous solids.展开更多
This paper investigates a power control problem in a jamming system,where a separate smart jammer is deployed to ensure the communication security of the legal user.However,due to power leakage,the smart jammer may in...This paper investigates a power control problem in a jamming system,where a separate smart jammer is deployed to ensure the communication security of the legal user.However,due to power leakage,the smart jammer may incur unintentional interference to legal users.The key is how to suppress illegal communication while limit the negative impact on legal user.A jamming counter measure Stackelberg game is formulated to model the jamming power control dynamic of the system.The smart jammer acts as a leader to sense and interfere illegal communications of the illegal user,while the illegal user acts as a follower.In the game,the impact of uncertain channel information is taken into account.According to whether illegal user considers the uncertain channel information,we investigate two scenarios,namely,illegal user can obtain statistical distribution and accurate information of interference channel gain and its own cost,respectively.This work not only proposes a jamming counter measure iterative algorithm to update parameters,but also gives two solutions to obtain the Stackelberg equilibrium(SE).The power convergence behaviours under two scenarios are analyzed and compared.Additionally,brute force is used to verify the accuracy of the SE value further.展开更多
Diversity combining technologies are analyzed for fast frequency-hopping spread spectrum systems during partial-band noise jamming to develop a novel combining receiver called an Adaptive Threshold Clipper Combining R...Diversity combining technologies are analyzed for fast frequency-hopping spread spectrum systems during partial-band noise jamming to develop a novel combining receiver called an Adaptive Threshold Clipper Combining Receiver (ATCCR). The optimal clipping level for an ATCCR is analyzed, computed, and compared with several other diversity combining technologies. Since the ATCCR can estimate the power of the jamming and the number of jammed frequency cells to adaptively adjust the clipper's threshold, the system performance using the adaptive threshold clipper combining technique can be greatly improved.展开更多
为提高合成孔径雷达(synthetic aperture radar,SAR)系统对抗转发式欺骗干扰的性能,提出一种基于非线性调频(non-linear frequency modulation,NLFM)信号的正交波形设计与优化技术,结合自主收发策略来优化波形组,使捷变发射的波形相互正...为提高合成孔径雷达(synthetic aperture radar,SAR)系统对抗转发式欺骗干扰的性能,提出一种基于非线性调频(non-linear frequency modulation,NLFM)信号的正交波形设计与优化技术,结合自主收发策略来优化波形组,使捷变发射的波形相互正交,从而达到在复杂环境下抑制转发式欺骗干扰的效果。首先,分析SAR系统转发式欺骗干扰的机理、波形捷变发射方法的合理性和有效性,提出利用正交波形设计进行抗干扰的方法;其次,采用S曲线法和分段函数法产生NLFM信号,基于拉格朗日算法,结合遗传算法对NLFM信号的波形组进行了优化设计;最后,通过仿真实验验证了本文方法设计的优化波形组在SAR系统中对抗转发式欺骗干扰的有效性。结果表明:由分段函数法产生NLFM波形后,在合适的干扰转发时延下,采用拉格朗日遗传算法优化NLFM波形的正交性,改善了波形的主瓣宽度和峰值旁瓣比,增强了捷变波形的正交性,提高了波形质量。展开更多
Multi-beam antenna and beam hopping technologies are an effective solution for scarce satellite frequency resources.One of the primary challenges accompanying with Multi-Beam Satellites(MBS)is an efficient Dynamic Res...Multi-beam antenna and beam hopping technologies are an effective solution for scarce satellite frequency resources.One of the primary challenges accompanying with Multi-Beam Satellites(MBS)is an efficient Dynamic Resource Allocation(DRA)strategy.This paper presents a learning-based Hybrid-Action Deep Q-Network(HADQN)algorithm to address the sequential decision-making optimization problem in DRA.By using a parameterized hybrid action space,HADQN makes it possible to schedule the beam pattern and allocate transmitter power more flexibly.To pursue multiple long-term QoS requirements,HADQN adopts a multi-objective optimization method to decrease system transmission delay,loss ratio of data packets and power consumption load simultaneously.Experimental results demonstrate that the proposed HADQN algorithm is feasible and greatly reduces in-orbit energy consumption without compromising QoS performance.展开更多
文摘针对侦察干扰一体化系统面向无人平台小型化载荷应用的场景,提出一种基于射频片上系统(radio frequency system on chip,RFSoC)的宽带侦察干扰一体化、小型化系统的设计与实现方法。重点攻克并行实时大带宽侦察干扰技术以及小型化、大带宽侦察干扰一体化软硬件系统构建,并改善和差波束比相测角算法在宽带测角时的测角精度以及间歇采样转发干扰算法的欺骗干扰效果。最后,基于该软硬件系统完成侦察干扰算法实现,验证系统具有优越的侦察定位精度与干扰性能。
文摘Amorphous systems undergo the jamming transition when the density increases, temperature drops, or external shear stress decreases, as described by the jamming phase diagram which was proposed to unify different processes such as the glass transition, random close packing, and yielding under shear stress. At zero temperature and shear stress, the jamming transition occurs at a critical density at Point J. In this paper, we review recent studies of the material properties of marginally jammed solids and the glassy dynamics in the vicinity of Point J. As the only singular point in the jamming phase diagram, Point J exhibits special criticality in both mechanical and vibrational quantities. Dynamics approaching the glass transition in the vicinity of Point J show critical scalings, suggesting that the molecular glass transition and the colloidal glass transition are equivalent in the hard sphere limit. All these studies shed light on the long-standing puzzles of the glass transition arid unusual properties of amorphous solids.
基金supported in part by National Key R&D Program of China under Grant 2018YFB1800800by National NSF of China under Grant 61601490,61801218,61827801,61631020+3 种基金by the open research fund of Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space(Nanjing Univ.Aeronaut.Astronaut.)(No.KF20181913)in part by State Key Laboratory of Air Traffic Management System and Technology under SKLATM201808in part by the Natural Science Foundation of Jiangsu Province under Grant BK20180420,BK20180424by the Open Foundation for Graduate Innovation of NUAA(Grant NO.kfjj20190417)。
文摘This paper investigates a power control problem in a jamming system,where a separate smart jammer is deployed to ensure the communication security of the legal user.However,due to power leakage,the smart jammer may incur unintentional interference to legal users.The key is how to suppress illegal communication while limit the negative impact on legal user.A jamming counter measure Stackelberg game is formulated to model the jamming power control dynamic of the system.The smart jammer acts as a leader to sense and interfere illegal communications of the illegal user,while the illegal user acts as a follower.In the game,the impact of uncertain channel information is taken into account.According to whether illegal user considers the uncertain channel information,we investigate two scenarios,namely,illegal user can obtain statistical distribution and accurate information of interference channel gain and its own cost,respectively.This work not only proposes a jamming counter measure iterative algorithm to update parameters,but also gives two solutions to obtain the Stackelberg equilibrium(SE).The power convergence behaviours under two scenarios are analyzed and compared.Additionally,brute force is used to verify the accuracy of the SE value further.
文摘Diversity combining technologies are analyzed for fast frequency-hopping spread spectrum systems during partial-band noise jamming to develop a novel combining receiver called an Adaptive Threshold Clipper Combining Receiver (ATCCR). The optimal clipping level for an ATCCR is analyzed, computed, and compared with several other diversity combining technologies. Since the ATCCR can estimate the power of the jamming and the number of jammed frequency cells to adaptively adjust the clipper's threshold, the system performance using the adaptive threshold clipper combining technique can be greatly improved.
文摘为提高合成孔径雷达(synthetic aperture radar,SAR)系统对抗转发式欺骗干扰的性能,提出一种基于非线性调频(non-linear frequency modulation,NLFM)信号的正交波形设计与优化技术,结合自主收发策略来优化波形组,使捷变发射的波形相互正交,从而达到在复杂环境下抑制转发式欺骗干扰的效果。首先,分析SAR系统转发式欺骗干扰的机理、波形捷变发射方法的合理性和有效性,提出利用正交波形设计进行抗干扰的方法;其次,采用S曲线法和分段函数法产生NLFM信号,基于拉格朗日算法,结合遗传算法对NLFM信号的波形组进行了优化设计;最后,通过仿真实验验证了本文方法设计的优化波形组在SAR系统中对抗转发式欺骗干扰的有效性。结果表明:由分段函数法产生NLFM波形后,在合适的干扰转发时延下,采用拉格朗日遗传算法优化NLFM波形的正交性,改善了波形的主瓣宽度和峰值旁瓣比,增强了捷变波形的正交性,提高了波形质量。
基金co-supported by the National Natural Science Foundation of China(No.U20B2056)the Office of Military and Civilian Integration Development Committee of Shanghai,China(No.2020-jmrh1-kj25).
文摘Multi-beam antenna and beam hopping technologies are an effective solution for scarce satellite frequency resources.One of the primary challenges accompanying with Multi-Beam Satellites(MBS)is an efficient Dynamic Resource Allocation(DRA)strategy.This paper presents a learning-based Hybrid-Action Deep Q-Network(HADQN)algorithm to address the sequential decision-making optimization problem in DRA.By using a parameterized hybrid action space,HADQN makes it possible to schedule the beam pattern and allocate transmitter power more flexibly.To pursue multiple long-term QoS requirements,HADQN adopts a multi-objective optimization method to decrease system transmission delay,loss ratio of data packets and power consumption load simultaneously.Experimental results demonstrate that the proposed HADQN algorithm is feasible and greatly reduces in-orbit energy consumption without compromising QoS performance.
