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61.
陈先福 《国防科技大学学报》1994,16(1):23-31
本文分析了跟踪干扰对跳频系统中码跟踪环性能的影响。它使参考码与接收码之间的相位误差均值偏移,相位误差方差增大,环路失锁慨率增加,以及间接地使误码率上升。 相似文献
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针对广义信道下伪码测距偏差与各部分通道测距偏差叠加值的等效性问题,研究星地叠加通道和部分通道特性对伪码测距偏差的影响,并对实际通道中伪距"分层"现象的成因展开分析。通道非理想特性会对导航信号伪码跟踪性能产生影响,综合考虑星地两端通道的非理想特性,通过对导航信号伪码跟踪函数和不同类型通道建模,研究了星地叠加通道和部分通道特性对伪码测距偏差的影响。结合几类典型星地非理想通道,利用软件接收机展开仿真验证。通过分析几类典型通道对伪码测距偏差的影响,解释了零基线双差观测量中伪距"分层"现象的成因。文中模型与相关分析方法可用于解释相关信号质量问题,并指导接收机通道的最优化设计。 相似文献
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在高精度伪码测距系统中,高功率放大器(HPA)是信号发射链路的重要组成部分,HPA会对发射信号引入非线性失真,进而恶化系统的伪码测距性能.通过理论推导和数值分析的方法,研究HPA的非线性特性对高精度伪码测距误差的影响,给出非线性放大条件下,伪码跟踪误差与放大器类型、放大器输出回退(OBO)、扩频码形参数等的定量关系.研究结果对工程上HPA的选择、功率余量的保留、基带扩频码形的设计等具有重要的参考价值. 相似文献
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针对现代装备测试性需求,利用ARM微处理器构建了基于CAN总线网络的多路嵌入式数据采集系统,介绍了嵌入式数据采集系统硬件组成、硬件模块实现以及软件设计;检测数据经过CAN总线存入SD卡存储器,并进行后期数据的存取和处理.实验结果表明,该系统能够可靠、准确地对多路信号进行采集,实现对火炮装备的检测. 相似文献
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This paper models transnational terrorism as a three‐way strategic interaction involving a government that faces armed opposition at home, which may spill over in the form of acts of terrorism by the state's opponents against the government's external sponsor. The external sponsor also utilises deterrence against potential terrorists, which only lowers terrorism if terrorists are not intrinsically motivated by a deep‐seated sense of humiliation. The model highlights the importance of intrinsic motivation. A rise in the external power's preference for deterrence against terrorism may backfire in these circumstances. Increases in the government's military efficiency against the rebels, who are also terrorists against the government's sponsor, raises overall levels of violence. 相似文献
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David L. I. Kirkpatrick 《Defence and Peace Economics》2013,24(4):263-288
This paper constructs a conceptual model for the selection of defence equipment providing best value for money. It then shows how the unit cost of the chosen equipment increases between one generation of equipment and its successor because of developments in the perceived threat, the available technology and industrial productivity, and demonstrates that unit cost increases can arise from a logical and rational procurement policy and are not necessarily caused by technological chimeras and military vainglory. The resulting persistent rise in unit cost is unlikely to be significantly slowed by any of the counter‐measures yet proposed. The paper then discusses the policies which nations have adopted to accommodate past increases in unit cost, and the options which confront any nation at the point when it can no longer afford to re‐equip a particular element of its armed forces. 相似文献
69.
《防务技术》2022,18(12):2181-2189
An adverse effect resulting from explosive mine blasts is the production of toxic nitrogen oxides (NO and NO2) and carbon monoxide (CO). The empirical measurements of the concentration of toxic gases showed that it depends not only on the composition of an explosive and properties of its ingredients but also on several other parameters, such as volume of blasting chamber, explosive charge mass and design, confinement characteristics, surrounding atmosphere, etc. That explains why measured concentrations of toxic gases reported in literature significantly differ.In this paper, we discuss the possibility of theoretical prediction of the concentration of toxic gases by thermochemical equilibrium calculation applying two models: ideal detonation model and deflagration model. It can be demonstrated that thermochemical calculations can provide a good estimation of the measured concentrations and reproduce experimentally obtained effects of additives on the production of toxic gases. It was also found that the ideal detonation model applies to heavily confined explosive charges, while the deflagration model is more suitable for low detonation velocity explosives with light confinement. 相似文献
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