战术数据链射频辐射特征控制技术

传统的链路自适应技术只追求高效数据传输,会导致射频暴露,在电子战中无法保障数据链载体的安全性。以战术数据链主动射频隐身和高效通信为研究对象,利用多目标优化技术联合控制战术数据链的射频辐射特征（包含辐射时间、辐射功率和辐射波形）,建立了一种战术数据链链路自适应技术模型。该模型以给定距离的截获概率和给定距离的可靠传输速率为二重优化目标,以辐射特征为优化变量,并以第四代宽带无线通信系统LTE-A (Long Term Evolution-Advanced) 的部分调制编码参数为实例,证实了由所述链路自适应技术模型优化所得的最优解可以同时实现数据链的射频隐身和高效数据传输。     

基于灰色关联算法的雷达反隐身性能评估

雷达反隐身的性能评估对现代空防战争具有重要意义。在深入分析雷达反隐身技术及相关基础理论基础上建立了雷达反隐身性能指标体系,提出了采用基于自适应熵权的灰色关联算法来进行雷达反隐身性能评估,解决了评价权重模糊问题,并结合经典最小二乘法和拉格朗日函数建立了优化评估模型,最后通过算例分析给出了该算法模型的应用过程,分析结果表明该算法能有效实现对雷达反隐身性能的排序和优选。     

雷达干扰射频隐身特性及自适应功率控制方法

针对战机实施有源干扰时的射频隐身问题,分析了现有干扰功率 评估准则的不足,在雷达信号检测模型和侦察截获概率模型的基础上,讨论了“有效干扰” 对干扰功率的需求和射频隐身对干扰功率的限制,提出将有效干扰条件下的侦察截获概率作 为干扰信号的射频隐身特性表征因子,最后提出了一种结合目标雷达类型、接收信号功率以 及本机RCS起伏等因素的干扰功率自适应控制方法。通过对固定功率干扰与不同压制系数下 自适应功率干扰时雷达检测概率和侦察截获概率的仿真,表明自适应功率控制能够节约干扰 功率,在有效干扰的同时提高干扰的射频隐身能力。     

改进的“当前”统计模型变采样率目标跟踪算法

为满足实际雷达系统对高精度和高实时性的要求,提出了一种改进的“当前”统计模型变采样率机动目标跟踪算法。该算法针对“当前”统计模型必须预设加速度极值和机动频率的问题,提出一种加速度方差和机动频率在线同步自适应方法,建立改进的“当前”统计模型机动目标跟踪算法;针对在线自适应方法计算量大的问题,结合采样周期的大小与目标机动特性的关系,引入变采样率方法。仿真结果表明,与传统“当前”统计模型相比,改进的“当前”统计模型机动目标跟踪算法能显著提高对不同机动强度目标的跟踪精度;变采样率方法通过减少采样点数,节省了系统资源,提高了跟踪实时性;所提算法将两者结合,用传统的“当前”统计模型1.5～2倍的平均采样周期得到了更小的位置均方根误差,实现了用单模型方法同时改善跟踪精度和实时性的目的。     

辐射时序对单站无源跟踪性能的影响

针对射频隐身平台采取辐射时序控制的情况,以基于角度/相位差变化率/多普勒频率变化率的单站无源跟踪为例,研究了辐射时序与跟踪性能的影响关系。在辐射源做匀速运动的假设下,采用克拉美劳下界方法,建立了辐射时序对跟踪性能的影响模型。模型综合考虑了辐射时序、观测量误差、导航误差等因素,与具体的跟踪算法无关,因此具有实用性和客观性。基于影响模型的仿真分析,揭示了辐射时序不同特征对跟踪性能的影响规律,为射频隐身平台辐射时序设计提供了初步的理论指导。     

一种利用运动补偿的改进JPDA-UKF算法

在恒虚警条件下,针对传统的航海雷达模拟器目标跟踪采用的基于不敏卡尔曼滤波的联合概率数据互联算法(JPDA-UKF)发散、复杂度高和实时性差的问题,提出了一种利用运动补偿的笛卡尔坐标下改进的JPDA-UKF滤波方法。该算法引入相邻周期回波间运动补偿提取的目标量测可信度矩阵,限制进入跟踪门相交区域中的虚假量测数量,并将软跟踪门技术应用于滑窗逻辑法实现航迹管理。仿真结果表明,所提方法径向速度误差比传统的JPDA-UKF算法与自适应的α-β滤波算法分别降低10%和20%,目标获得稳定航迹后径向速度归一化均方根误差(RMSE)比上述两种方法分别具有约10 dB和15 dB的性能优势,算法的复杂度符合真实雷达的边扫描边跟踪的实时处理。     

飞行器射频隐身技术及发展思路

射频隐身是武器平台对抗无源探测设备的重要技术手段,与雷达、红外隐身一起构成 作战平台的隐身能力。飞行器射频隐身性能是其作战能力和生存能力达成的重要因素。在对 飞行器典型有源传感器的使用和面临的威胁分析基础上,分析了飞行器射频隐身主要技术手 段,概括了飞行器射频隐身主要技术特点,提出了飞行器射频隐身技术的发展思路。     

一种基于跟踪精度控制的组网火控雷达抗ARM方法

分析了火控雷达目标跟踪及间歇辐射原理,提出了一种保精度抗反辐射导弹（ARM）方法。 该方法通 过改进递推式自适应滤波算法,实时控制跟踪精度,来调节组网火控雷达的辐射时间和规律 ,从而最大限度地降低雷达信号被截获的概率。从仿真结果可以看出,与正常工作雷达相比 ,该方法可以使火控雷达同时实现对反辐射导弹载机的准确跟踪和对反辐射导弹的有效对抗 。     

一种改进的机载多普勒雷达目标跟踪算法

针对传统的基于多普勒雷达量测转换的目标跟踪算法只适用于静止雷达的问题,将该算法推广至机载多普勒雷达。在每个递推周期里,首先将机载导航数据转换到东北天坐标系中;然后,将距离量测转换成东北天系下的位置伪量测,由此完成对目标的位置滤波;最后,联合目标位置滤波值及多普勒量测对目标进行运动状态滤波,由此得到目标的位置最终估计值。仿真实验结果表明,改进后算法的跟踪精度优于传统的多普勒雷达目标跟踪算法。     

一种改进的粒子滤波算法

在粒子滤波中,防止粒子退化的两个关键因素是选择适当的采样建议分布和重采样算法.针对建议分布的选择条件,提出了一种改进的粒子滤波算法,该算法采用强跟踪扩展卡尔曼滤波方法构建其建议分布.强跟踪扩展卡尔曼滤波可在线调节参数,从而使得系统具有更好的自适应性和鲁棒性,对高机动目标具有更强的跟踪效果.仿真结果表明,该算法的性能优于其它几种非线性滤波算法.     

Public Financial Expenditure——A Reflection of the Livelihood Improvement

In recent years.China's public finance put social construction high on the agenda and attaches more importance on livelihood insurance and improvement.The 2003-2007 public financial expenditure reflects a fact that the government isputting more emphasis on livelihood andissues concerning the people.     

Voices from the MPC and CPPCC

"Crucial for economic growth.energy utilization has its role in all economic sectors and every aspect of people's daily life.Now we are in dire need of a new profession,namely energy manager.We not only need to have passion and responsibility,but also a scientific approach to conserve energy and cut emissions.APpropriate legislation should be in place.and a special profession should be introduced to ensure the implementation of these laws and regulations."     

Slowdown Trade Surplus Growth

According to Ma Kai＇s economic planning report submitted to the NPC session on March 5th,（Ma Kai is the Minister in charge of the National Development and Reform Commission）,the government has listed the slowdown in trade surplus growth and the steady expansion of external investment as major tasks for 2008.     

Ouyang Riping： A Hero Besides Entrepreneur

A bout fifty years ago. a baby＇s cry broke the sky of quietness, in a small and beautiful town of Hunan province, which surroundcd by green hills and clear water. Though his .birth brought his family great happiness and hope just as any new life, nobody knew that the little boy would get great achievement when he grow up. even start his business oversea, and earn international honor. Let＇s share with you the entrepreneur Ouyang Riping＇s story, which may insights thcsc people who want to succeed and complete oneself in favorite condition or adversity rather leave things to so-called fate.     

Belarus, A Chinese Fort in Europe

＂In recent years, we＇ve found increasing interest from Chinese investors in the Belarus economy. Please let China know, Belarus is always ready to be a true friend to China. We have built a fort in Europe for China,＂ the President of Belarus, Alexander Lukashenko told Zhou Xiaochuan, President of the Bank of China, during his visit to the capital of Minsk, on January 8th, he expressed his high praise and firm confidence in the development of Sino-Belarusian relations.     

What＇s Behind Spring Festival？

Similar to what the Christmas Day means for the westerners,the Spring Festival is the most important celebration for Chinese people.This big event according to Chinese traditional lunar calendar relaxes and pleases the whole country as the happiest gathering time of the year.National-wide crusade for going back home,too-difficult-to-get train tickets,generous family-going-out shopping,Miaohui laundering,New Year Eve reunion dinner,visiting friends and relatives,watching annual TV gala......each piece of clue reminds us of the smell of Chinese Spring Festival.     

KEY WDRDS for Foreign Investment in China

FDI(Foreign Direct Investment),a component of a country's national financlal accounts,is investment of foreign assets into domestic structures,equipment,and organizations.It does not include foreign investment into the stock markets,concession and subcontract.FDI iS thought to be more useful to a country than investments in the equity of its companies because equity investments are potentially "hot money"which can leave at the first sign of trouble,whereas FDI is durable and generally useful whether things go well or badly.     

Universal Coverage, Pinpoint Illustration and Profound Impact HTC 2008 Intermedia Recommendation and Introduction Meeting

Holding 88 percent of train media resources across China, based on "Time Cube", on the 2008 Intermedia Recommendation and Introduction Meeting on December 19, 2007, HTC announced its high-profile strategy of tour marketing and tapping the immeasurable potentials on the train. Meanwhile, HTC officially launched its brand new product Olympic Train on the meeting, providing a fabulous platform for all the brands that are prepared to do a smart marketing on the occasion of 2008 Olympic Games.     

Market presence in China strengthened Network growth and Dual-Chinese-Hub Strategy More frequet Flyer Benefit——Air China and shanhai Airlines Join Star Alliance

In the end of 2007, Air China Limited (hereinafter "Air China") and Shanghai Airlines, formally joined Star Alliance at a ceremony held in the new Terminal Three at Beijing Capital International Airport. With the addition of the two Chinese airlines, Star Alliance now has 19 member carriers operating 17,000 daily flights to 897 destinations in 160 countries.     

Brown＇s Blossom in Britain-China

The overall strategic relationship between U.K. and China is ＂better than ever＂, China- Britain relations have maintained good momentum, with increased high-level exchanges and the reinforcement of strategic mutual trust, with more room for growth in the future.