Turbo均衡的误码率性能分析及应用

对Turbo均衡系统中的分量编码器、约束长度、交织长度、迭代次数、码率等参数进行了系统分析,在log-MAP算法基础上,仿真出了这些参数与误码率之间的定量关系,并分析了Turbo均衡在高斯白噪声信道和瑞利信道中的不同表现,为Turbo均衡的具体应用提供了可靠的参数选择依据。针对短波信道不稳定,短波电台数传误码率高的情况,设计了以Turbo均衡为核心的无线增强解决方案,并通过仿真验证了其在不同信噪比条件下降低误码率的效果。     

舰舰协同防空的舰空导弹杀伤区分析

针对舰艇编队协同防空时的耦合杀伤区形状及纵深等问题进行了研究,以定量地对编队耦合杀伤区进行简化描述。分析了单舰对典型目标的杀伤区特性,探讨了舰艇编队的典型防空队形,研究了纵向上递阶多层次、横向上同阶耦合的"递阶封闭圈原理"。以一阶耦合杀伤区为重点,依据攻击目标的不同,将其分成相对航路捷径为零和相对航路捷径均非零两类情况建立了耦合杀伤区纵深的计算模型,并扩展到了高阶耦合的情况。研究了耦合杀伤区与舰舰间距和来袭目标进攻舷角等参数的相互关系以及灵敏度。结果表明建立的模型符合实际,具有一定的指导意义。     

小载荷无人机无源定位技术研究

近年来,电子战设备和信号情报系统更加高效小型化,无人机可以携带的载荷种类不断增多.随着无人机的研究、设计和制造水平得到前所未有的提高,在无源定位领域开始发挥越来越重要的作用.从无源定位技术的分类入手,重点研究无人机无源定位的方式、对象和关键技术;以雷达辐射源为例,构建了小载荷无人机虚拟到达时间差(Virtual time differences of arrival,VTDOA)无源定位模型,讨论了对应的定位算法,并给出了仿真试验结论;最后根据最新研究成果展望了无人机无源定位技术的发展趋势.     

基于改进粒子群算法的火炮内弹道多参数符合计算

为了研究火炮在发射过程中膛内火药燃烧规律以及弹丸运动规律,需要建立火炮内弹道数学模型并进行数值求解,在此过程中对部分内弹道参数进行符合计算是优化内弹道模型的重要途经之一.在经典内弹道方程组的基础上,阐述了经典内弹道计算原理,并对基本粒子群算法进行了改进,使改进后的粒子群算法在迭代初期有较大的惯性权重ω和学习因子c1以及较小的学习因子c2,而在迭代后期有较小的惯性权重ω和学习因子c1以及较大的学习因子c2,从而有效地避免粒子群陷入局部最优而导致收敛精度低的缺陷.将改进后的粒子群算法应用于火炮内弹道多参数符合计算,算例结果表明该方法完全满足工程实际要求,具有收敛速度快、符合精度高的特性,是火炮内弹道多参数符合计算的理想算法之一.     

Mechanical behavior and failure mechanism of polyurea nanocomposites under quasi-static and dynamic compressive loading

Polyurea is an elastomeric material that can be applied to enhance the protection ability of structures under blast and impact loading.In order to study the compressive mechanical properties of SiC/polyurea nanocomposites under quasi-static and dynamic loading,a universal testing machine and split Hop-kinson pressure bar(SHPB)apparatus were used respectively.The stress-strain curves were obtained on polyurea and its composites at strain rates of 0.001-8000 s-1.The results of the experiment suggested that increase in the strain rates led to the rise of the flow stress,compressive strength,strain rate sensitivity and strain energy.This indicates that all of the presented materials were dependent on strain rate.Moreover,these mechanical characters were enhanced by incorporating a small amount of SiC into polyurea matrix.The relation between yield stress and strain rates were established using the power law functions.Finally,in order to investigate the fracture surfaces and inside information of failed specimens,scanning electron microscopy(SEM)and micro X-ray computed tomography(micro-CT)were used respectively.Multiple voids,crazes,micro-cracks and cracking were observed in fracture surfaces.On the other hand,the cracking propagation was found in the micro-CT slice images.It is essential to understand the deformation and failure mechanisms in all the polyurea materials.     

Repeater jamming suppression method for pulse Doppler fuze based on identity recognition and chaotic encryption

Pulse Doppler (PD) fuze is widely used in current battlefield. However, with the threat of repeater jamming, especially digital radio frequency memory technology, the deficiency in the anti-repeater jamming of a traditional PD fuze increasingly emerges. Therefore, a repeater jamming suppression method for a PD fuze based on identity (ID) recognition and chaotic encryption is proposed. Every fuze has its own ID which is encrypted with different chaotic binary sequences in every pulse period of the transmitted signal. The thumbtack-shaped ambiguity function shows a good resolution and distance cut-off characteristic. The ability of anti-repeater jamming is emphatically analyzed, and the results at different signal-to-noise ratio (SNR) show a strong anti-repeater jamming ability and range resolution that the proposed method possesses. Furthermore, the anti-repeater jamming ability is influenced by processing gain, bit error rate (BER) and correlation function. The simulation result validates the theo-retical analysis, it shows the proposed method can significantly improve the anti-repeater jamming ability of a PD fuze.     

半导体量子点光吸收谱线亚结构的PLE谱分析

用半导体量子点的PLE谱分析了光吸收谱的亚结构.用光吸收谱,光致发光谱(PL)和光致发光激发光谱(PLE)对半导体CdSeS量子点玻璃进行了测量.光吸收谱线有明显的量子尺寸效应.PL谱中出现2个发光峰.用PLE谱在光吸收谱的低能侧峰附近探测,发现光吸收谱的低能侧峰附近存在2个峰,其能量间距随着量子点半径的增大而减小,说明了光吸收谱的低能侧峰存在亚结构.证明了PL谱中低能侧峰为缺陷态发光,该峰的PLE谱线说明了该峰的发光来源于1S3/2-1se和2S3/2-1se2能态的电子,甚至更高能态电子的弛豫.     

论信息化条件下战场空间的嬗变

随着信息技术在战争中的广泛应用,战场空间正在由传统的陆、海、空三维空间向自然空间、非自然空间和认知空间拓展,并且已经初步形成了七维一体作战空间的雏形,战场空间也呈现出与以往不同的宏观化、微观化、虚拟化和无序化的新特点;在分析各作战空间辩证关系的基础上,提出了对未来我军现代化建设的几点启示.     

一种跳码直扩通信技术体制探讨

针对传统直扩通信技术体制在军事通信应用中存在的不足,提出了一种新型跳码直扩通信技术体制及其扩展型跳码/跳频混合扩谱通信技术体制,分析了其基本性能,该体制可望解决常规直扩通信技术体制中的一些难题,提高军事通信中直扩通信系统的反侦察能力。     

基于ABA处理和幅度加权的频率捷变单脉冲雷达角闪烁抑制技术

针对频率捷变幅度加权角闪烁抑制方法进行改进,提出了一种基于ABA(amplitude-based angle)处理的幅度加权角闪烁抑制方法。首先将单个脉冲测角的结果限制在一定范围内,然后对多个脉冲测角的结果进行幅度加权,仿真表明这种方法在各种信噪比条件下的角闪烁抑制性能都要大大优于常规的幅度加权方法。