【摘 要】
：
Due to the rapid development of electronic countermeasures (ECMs), the corresponding means of electronic counter countermeasures (ECCMs) are urgently needed. In this paper, an act-ive anti-jamming method based on frequency diverse array radar is proposed.
【机 构】
：
Air and Missile Defense College, Air Force Engineering University, Xi’an 710051, China
论文部分内容阅读
Due to the rapid development of electronic countermeasures (ECMs), the corresponding means of electronic counter countermeasures (ECCMs) are urgently needed. In this paper, an act-ive anti-jamming method based on frequency diverse array radar is proposed. By deriving the closed form of the phase center in a uniform line array FDA, we establish a model of the FDA signal based on adaptive weights and derive the effect of active anti-jamming in this regime. The pro-posed active anti-jamming method makes it difficult for jammers to detect or locate our radar. Fur-thermore, the effectiveness of the two frequency increment schemes in terms of anti-jamming is ana-lyzed by comparing the deviation of phase center. Finally, the simulation results verify the effective-ness and superiority of the proposed method.
其他文献
钢中夹杂物的去除一直是洁净钢研究的热点,对于提高钢材质量、保障产品性能具有重要意义.?钢液中夹杂物主要通过上浮至顶渣被吸收而去除,这个过程可细分为夹杂物在钢液中长大上浮、在钢?渣界面穿越分离、在熔渣中被吸附溶解3个步骤.?钢?渣两相的物性差异及界面特性导致不符合条件的夹杂物无法穿过界面与钢液分离,这使得该步骤成为夹杂物去除的决定性环节,且由于钢?渣两相周围快速的物性过渡、并行的物理化学现象以及高温、不透明等特性影响,使该步骤研究难度增大.?近年来,随着数值模拟技术和高温实验设备的进步,夹杂物穿越钢?渣界面
为研究压下对连铸坯内部裂纹产生的影响,利用ABAQUS有限元软件建立了230 mm×280 mm断面大方坯压下数学模型.通过压下模型对重轨钢连铸坯压下过程进行热力耦合模拟计算,对压下过程中产生的内部裂纹进行了预测.首先,对连铸坯不同中心固相率为0.3～0.7的温度场进行计算;然后,利用压下模型计算了连铸坯中心固相率0.3～0.7时凝固前沿的等效塑性应变.研究结果表明,在连铸坯中心固相率为0.3～0.7的位置处分别施加7 mm压下量进行压下,连铸坯凝固前沿等效塑性应变未超过临界等效塑性应变(0.4％),连铸
在现有工艺条件下,校验和完善二冷区铸坯凝固传热计算数学模型,开发三维二冷配水模型,解决目前设备状况下冷却水分布不均匀对铸坯温度的影响,从而控制铸坯表面质量,特别是铸坯的角部裂纹,同时对板坯连铸二冷配水制度进行改进和优化,使之满足高效连铸生产条件和改善铸坯质量的需要.提出压下参数计算公式,结合所开发三维二冷配水模型,优化现有压下工艺,提出并应用精准可控单段压下、非稳态压下控制,集中解决连铸板坯中心偏析、中心疏松和缩孔等内部质量问题.同时优化模型数据库,使之数据更加完备,模型计算更加准确,同时模型具备异钢种混
为研究古塔子结构的受力性能,设计制作了3件不同楼层的子结构缩尺模型试件,进行低周反复加载试验,观察试件的开裂、变形及破坏现象;建立数值模型进行计算,得到了试验荷载作用下各试件的等效塑性应变、荷载?位移曲线,将计算结果与试验结果进行对比,分析竖向压应力对古塔砌体抗震性能的影响.?结果表明,特征荷载的计算值相对试验值的误差均小于21％,等效塑性应变的分布与试件开裂破坏区域一致;当竖向压力保持恒定时,随着水平荷载的增大,塔体沿砌筑缝逐渐开裂破坏,裂缝宽度亦随之增大,在塔体洞口周围的破坏更为明显,且试件残余变形增
Direction of arrival (DOA) estimation for unfolded coprime array (UFCA) is discussed, and a method based on subspace compensation is proposed. Conventional DOA estimation meth-ods partition the UFCA into two subarrays for separate estimations, which are t
Long-time coherent integration (LTCI) can remarkably improve the detection ability of radar for moving target. To increase the processing efficiency, this paper proposes a novel LTCI method based on segment time reversing transform (STRT) and chirp z-tran
Efficiently performing high-resolution direction of arrival (DOA) estimation under low signal-to-noise ratio (SNR) conditions has always been a challenge task in the literatures. Obvi-ously, in order to address this problem, the key is how to mine or reve
基于K均值聚类法对转炉出钢过程的合金损耗进行了研究,分析了影响合金损耗的关键因素,并将其分为3个聚类,得到转炉出钢合金损耗最低的工艺模式.在此基础上,开发了基于PCA-BP神经网络和混合整数线性规划的合金减量化智能控制系统,并以某炼钢厂为例进行了实际应用.通过对模型进行在线运行,验证了模型的准确性和实用性.使用该模型后,提高了合金化钢液成分准确度,减少由传统人工经验计算配料造成的成本浪费和成分超标等情况,优化了合金配料方案,降低了炼钢合金化成本,不同钢种铁合金加入总成本降低5.95％～14.74％,平均降
Usually, the problem of direction-of-arrival (DOA) estimation is performed based on the assumption of uniform noise. In many applications, however, the noise across the array may be nonuniform. In this situation, the performance of DOA estimators may be d
基于建立的连铸中间包及结晶器内钢液混合过程的物理模型,开发了板坯连铸异钢种连浇过程混浇坯长度及成分变化模型.?以某钢厂单流板坯连铸机220?mm×1560?mm断面Q235与Q335Ti钢的混浇过程为研究对象,采用水模型试验结合数值模拟确定模型的关键参数,并通过开展现场试验对混浇坯取样验证模型的准确性.?结果证明:混浇坯成分取样与模型预测的成分偏差小于5％,且模型预测的混浇坯长度与人工确定的一致.?故采用该模型可跟踪不同混浇工况下中间包内及铸流上钢液的混合行为,准确预测混浇坯的长度以及成分变化规律.?采用