飞航导弹火控系统动态精度试验数据处理方法

飞航导弹火控系统动态精度试验后获得的导弹射击诸元误差序列一般为非平稳的随机过程,根据此误差特性,提出了动态测量数据的异常值数据处理方法,建立射击诸元误差序列、将误差序列分解为慢变化信号和高频噪声信号,最后给出火控系统射击诸元参数的最大误差统计估值方法     

雷达角跟踪误差的建模与处理

角跟踪误差是一典型的非平稳随机过程。传统的分析是分段平稳化处理,但这种方法分析的精度较低。本文建立了一种时变AR数学模型,通过把模型系数用距离的拉格朗日多项式基展开,从而把模型系数的时变性转化为基的时变性。论文还讨论了正交辨识和最小二乘在线递推两种辨识算法,并对后者的实时性作了较详细的分析。利用时变 A R数学模型,对一仿真角跟踪误差序列进行了建模,结果同理论值非常吻合。论文还对一实测数据进行了建模和分析,并把结果同传统分段平稳化分析结果作了比较。     

舰炮火控雷达实测误差时序特性分析建模

针对舰炮火控雷达高精度实时仿真建模的问题,运用高斯分布和正态平稳过程的两种误差序列生成方法,建立火控雷达简化仿真模型。通过对某火控雷达实测数据误差的统计及时序相关性分析,完成误差序列仿真生成与验证,给出了实现舰炮火控雷达探测误差仿真的优选方法。实践证明,正态平稳模型的误差生成方法可以有效满足新型舰炮仿真试验火控雷达建模要求。     

一种基于SVD的非平稳信号重叠分段降噪算法

在分析基于SVD的平稳信号降噪原理的基础上,提出了一种基于SVD的非平稳信号重叠分段降噪算法.非平稳信号通过数据分段可近似处理为多段平稳信号.为降低连续分段降噪误差,进行一定比例的重叠分段,应用基于SVD的平稳信号降噪方法对各分段信号进行降噪,相邻段之间的重叠信号经过多次降噪后求平均得到最终降噪信号.仿真结果表明,该算...     

捷联式速率陀螺仪漂移误差的分析和估算

本文从比较平台式与捷联式惯导系统的陀螺仪角度出发,叙述了飞行器捷联惯导系统对陀螺仪性能的要求;推导了动态环境下捷联速率陀螺仪的数学模型及其漂移误差的数学模型;对漂移误差进行了分析,并给出了漂移误差的表达式;最后,用平稳随机过程理论估算了动态环境下捷联速率陀螺的动态误差。     

量测误差的时间序列分析方法

针对工程实践中实际量测误差大多并非纯白噪声特点,运用概率统计学的一个分支——时间序列分析中提供的动态数据处理的方法,采用多种的参数估计算法来对量测误差进行拟合和仿真,给出了实验室仿真过程中需叠加的量测误差的新生成办法。所用方法可以推广到对其它数据序列的处理。     

装甲车辆行进间炮口振动角度误差预测模型

针对射击延时过程中具有振荡性的装甲车炮口振动角度误差数据,提出了一种优化的GM(1,1)预测模型。对原始数据进行光滑性和单调性处理;对传统GM(1,1)模型的初始值进行了基于拟合误差最小化的改进;基于传统模型中背景值构造方法存在的误差,重构了传统模型的背景值。通过对高低向、方位向两组数据处理结果的分析,优化GM(1,1)模型的拟合、预测结果相对于传统模型、改进初始值模型和改进背景值模型具有较小的误差,能够较好地反映装甲火炮炮口振动角度误差的变化情况。     

改进的变步长LMS自适应滤波算法分析

通过建立步长因子μ与误差信号e(n)之间的非线性函数关系,提出了一种改进的自适应变步长最小均方(LM S)算法。该算法克服了LM S算法在自适应稳态阶段μ取值偏大的缺陷,具有在误差e(n)接近零处缓慢变化的特点。该算法还具有初始阶段和未知系统时变阶段步长自动增大而稳态时步长很小的特点,解决了收敛时间和稳态误差的矛盾。将该算法对比一般的变步长算法,该改进算法在平稳过程中具有更小的稳态误差,同时还具有更好的跟踪时变系统的能力。     

对机动目标的滤波和预测研究(上)

因反超音速导弹和末端机动导弹的需求,必需解决对机动目标的跟踪滤波和预测问题.根据对机动目标运动特性和噪声特性的分析,指出不能用处理平稳随机过程的最佳滤波方法来处理非平稳随机过程的滤波问题.利用自动控制理论、自适应控制方法和误差相消技术,构建了对付机动目标的滤波器,并给合常用的几条航路和一条完整的末端机动导弹航路,进行了...     

北斗三号系统中轨道地球卫星伪距多路径误差分析和改正

2018—2019年,北斗三号系统陆续发射十几颗中轨道卫星,逐步完成全球组网。北斗三号系统卫星同时播发平稳过渡信号B1I、B3I和新体制信号B1C、B2a。实际数据分析表明,中轨道地球卫星民用B1C和B1I频点包含明显的伪距多路径误差,并且由于中轨道地球卫星的轨道特性,这种现象在卫星低高度角,即出入境时十分显著。利用多路径半天球图(Multipath Hemispherical Map, MHM)与伪距噪声和多路径校正法(Code Noise and Multipath Correction, CNMC)两种算法对伪距多路径误差进行改正。MHM算法对伪距多路径误差的改正并不明显;CNMC算法在高度角大于30°时可以将B1C频点伪距多路径误差从0.11 m降低至0.03 m,将B1I频点伪距多路径误差从0.074 m降低至0.024 m,从而使中轨道卫星的多路径误差降低60%以上。     

Helping hands: civil–military cooperation and Italy's military operation abroad

In the Post-Bipolar Era the growing complexity of the military operations requires a new approach for the resolution of international crises. Since the end of the Cold War, peace support operations (PSO) have become the mainstay and principal occupation of most Western armies. At the same time, Italy has been one of the most important actors in such an area. The article focuses on the cooperation between military and civil components (a process called CIMIC) as a key variable in the Italian PSOs. We will analyse in detail the main lessons learned from past military interventions as well as the general context in which new tendencies are taking place. The maintaining of a minimum security frame becomes essential to fulfil activities ‘collateral’ to the mission: reconstructing services and infrastructure, food distribution, water and medication, law and order, de-mining, training of local forces, and supporting local institutions. These are the main tasks to obtain thrust and support from the population.     

Terrorism,insurgency, kidnapping,and security in Africa's energy sector

Energy continues to serve as the bedrock of modern economies and the main driver of modern society. For Africa, the production and supply of energy resources such as crude oil, natural gas, uranium, coal, biomass, biofuels and other renewables are an important source of employment, rents, taxes, royalties and profits. This sector brings in several tens of billions of dollars of revenue annually. The production and delivery of such resources, however, depend on critical infrastructures such as pipelines, refineries, processing plants, terminals, rigs, electrical energy pylons, substations, pump stations, vessels, and tankers. These infrastructures have been attacked by terrorists, insurgents, vandals and saboteurs, all of whom see them as targets against which to register their grievances and extract concessions from the state. This paper is a chronological account of some of the documented incidents of terrorism, insurgency, kidnapping, destruction, sabotage, and human casualties suffered in the oil and gas sectors in Africa between 1999 and 2012. It is based on data extracted from the databases of the RAND Database of World Terrorism Incidents and the University of Maryland's Global Terrorism Database (GTD).     

Tacit support for terrorism: The rapprochement between the USSR and Palestinian guerrilla organizations following the 1967 war

This article demonstrates the inconsistent and wavering Soviet attitude towards national liberation movements in general and the Palestinian organizations in particular. Until the late 1960s, the Soviets viewed these organizations with suspicion, hesitating to engage in political dialogue with them. However, in the 1970s, political and military events in the region, as well as modifications in the Kremlin's Cold War strategies, led to a general shift towards the Middle East in Soviet foreign policy. Soviet leaders showed increased willingness to provide certain Palestinian organizations with arms with which to conduct terrorist activities against Israeli, pro-Israeli, Jewish and Western targets. The article explores the complex relations between Palestinian organizations and the USSR in the field of international terror. The study also exposes and analyzes the nature and content of Soviet–Palestinian arms dialogues and transactions. It provides clear evidence that Soviet policymakers and other luminaries were fully informed of, and sometimes directly involved in, these transactions and dialogues at the highest levels.     

A1 Qaeda and the radical Islamic challenge to western strategy

The September 11 global crisis prompted by the attacks on the World Trade Center and the Pentagon raises major questions concerning the nature and trajectory of terrorism in the post-Cold War global order. Hitherto, terrorism has been largely debated by analysts at the level of nation states. Terrorist and insurgent movements have also been largely anchored in nationalist and ethnic power bases even when they have sought to mobilise a transnational ideological appeal on religious or class grounds. There have been a few exceptions to this pattern such as the alliance between the German Baader-Meinhof group and the Japanese Red Army Faction, but even such international alliances as this did not, until at least the 1980s, presage anything like a global terrorist network necessitating a global strategic response. This study examines terrorism and global strategic responses.     

Reviews

Douglas S. Derrer, We Are All the Target: A Handbook of Terrorism Avoidance and Hostage Survival. Annapolis, MD: US Naval Institute Press, 1992. Pp. x+135, notes, index. $14.95. ISBN 01–55750–150–5

Ian Knight, Zulu: Isandlwana and Rorke's Drift, 22–23 January 1879. London: Windrow & Greene, 1992. Pp.136, 150 illus., incl 8 colour plates, maps, biblio. £35. ISBN 1–872004–23–7

Ian Knight, By the Orders of the Great White Queen: Campaigning in Zululand through the Eyes of the British Soldiers, 1879. London: Greenhill Books and Novato: Presidio Press, 1992. Pp. 272, 17 illus., 1 map. £18.95. ISBN 1–85367–122–3

Manfried Rauchensteiner and Erwin A. Schmidl (eds.), Formen des Krieges: vom Mittelalter zum ‘Low‐intensity’ Conflict’. Graz : Verlag Styria, 1991. Pp.208. DM35. ISBN 3–22–12139–7

Harold J. Kearsley, Maritime Power and the Twenty‐First Century. Dartmouth: Dartmouth Publishing Company, Limited, 1992. Pp.xv + 203, 13 diagrams, index. £32.50. ISBN 1–85521–288–9     

Helping hands: external support for the KNU insurgency in Burma

This article analyses to what extent the Burmese KNU insurgency made use of external support from states, refugees, and diasporas. Based on extensive fieldwork it is concluded that support from neighbouring states and refugees has for years kept the Karen rebellion alive. Western countries perceived forms of resistance to the illegitimate Burmese regime as just and have therefore played a crucial role in the continuation of conflict in Karen State. It is important that policymakers and donors as well as executing organizations continue to reflect critically on the way they exercise their work.     

基于GTST-DMLD-ESD的装备RMS建模仿真

装备的RMS是装备的重要设计参数,是影响战备完好和保障能力的关键因素.引入GTST-DMLD作为主要建模工具,建立起装备系统的RMS描述模型,以ESD为补充和扩展,对维修过程进行建模.并以GTST-DMLD-ESD模型作为装备RMS仿真的核心,对装备RMS仿真模型的总体框架进行了研究,并对各模块进行了较为详细的探讨.     

Panjwai: a tale of two COINs in Afghanistan

The US Army has two approaches to counterinsurgency operations in Afghanistan. One is hard, or combat-focused, and the other is soft, or development-focused. This study examines two US Army task forces deployed to Panjwai District, Afghanistan from 2012 to 2013. CTF 4-9 and 1-38 offer a meaningful comparison because they pursued these contrasting approaches among the same population and against the same enemy at the same time and place. The study compares each unit’s approach and finds that neither approach was successful absent the other. The article concludes by recommending further research into combining the approaches at the operational level.