共查询到19条相似文献,搜索用时 109 毫秒
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以导弹攻防对抗中防御雷达对空间目标的微多普勒频率检测为背景,分析了雷达部署位置对进动目标微多普勒测量值的影响.理论上可证明,当目标的外形尺寸和进动参数确定后,微多普勒频率由进动轴和雷达视线的夹角(平均视线角)唯一决定.从雷达部署在弹道平面内不同区域以及雷达距弹道平面不同距离两方面出发,分析了微多普勒调制带宽随雷达位置的... 相似文献
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转角估计是逆合成孔径雷达成像中的基本问题,得到的横向定标后图像可实现目标真实外形和尺寸等特征的提取,并为目标的参数估计和分类识别提供基础。针对三维转动的旋转对称目标,由于其转角变化的高度非线性,提出了一种基于旋转匹配特性的转角估计方法。基于旋转对称目标的三维转动模型,首先对目标在径向距离—速度差平面上的旋转匹配关系进行了证明和分析。进而,基于最优化准则,在雷达视线角二阶多项式近似下完成转角估计。仿真实验以进动锥柱体为例,在一个进动周期上对等效转速进行估计,结果表明算法在几乎所有的成像时刻都能有效估计目标转角。同时,实验还分析了散射点个数对转角估计性能的影响。 相似文献
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针对天空双基地雷达高速机动目标的距离徙动和多普勒频谱扩展问题,在建立目标回波信号模型及分析目标距离和多普勒徙动特性的基础上,提出了一种适用于该体制雷达的高速机动目标检测方法。首先对脉压回波信号采用Keystone变换校正距离徙动;其次对离散线性调频傅里叶变换(discrete chirp-Fourier transform,DCFT)进行修正,完成对目标加速度大小和频率因子的估计;然后根据构造的二次相位补偿函数,实现多普勒徙动补偿;最后对补偿后回波信号进行相参积累检测。仿真结果表明,所提方法对目标径向加速度的估计更准确能有效对高速机动目标回波能量进行相参积累,提高了在低信噪比条件下的检测性能。 相似文献
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《防务技术》2010,(1)
A nonlinear mathematic model taking the nutation and precession angles as variables for the coning motion of projectile was established according to a short period moment projection of the spining projectile. By introducing the generalized nutation angle and precession angular speed, the model that is difficult to be resolved can be transformed to a resolvable one. The interrelationship between nutation and precession was analyzed based on the linear model, and the stability condition was obtained for the spinning projectile. For the nonlinear model, the effects of the nutation and precession on the limit circle of the projectile's coning motion were investigated, and the analytical relations between the nutation angle and the precession angular speed in the steady coning motion of the spinning projectile were given. 相似文献
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根据跟踪陀螺仪的工作原理,推导出了陀螺仪的跟踪方程及其解,分析了陀螺仪跟踪运动的力学实质——进行与章动。为了提高跟踪精度。消除章动现象是必要的。 相似文献
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分析了小采样周期条件下“当前”统计模型、基于速度估计的自适应模型及自适应常加速度模型,对3种模型的稳态性能和动态性能进行了分析比较,并对3种模型的机动目标跟踪效果进行了仿真。仿真结果表明:小采样周期条件下,3种模型的稳态跟踪性能一致,而在动态跟踪条件下自适应加速度模型性能更优。 相似文献
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加速寿命试验(ALT)可在较短时间内获得产品的寿命及可靠性信息.利用ALT对产品的剩余寿命进行评估时,常常将已工作过的产品进行抽样并投入试验,在这一类样本的ALT数据统计分析时如何处理初始工作时间,成为ALT应用中的一个重要问题.工程实际中评估此类样本的剩余寿命时常常忽略初始工作时间,将其视为"用后如新"或"无记忆性"产品.但此假设必须以产品寿命服从指数分布为前提,而大部分机电产品的寿命服从Weibull分布,因而该方法在应用时必然会产生较大误差.针对这一问题提出了一种新的基于时间折算的ALT数据统计分析方法,并利用Monte Carlo仿真对其估计特性进行对比研究,结果表明此方法能有效评估存在初始工作历程产品的剩余寿命,估计精度优于原方法. 相似文献
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Gordon P. Wright 《海军后勤学研究》1968,15(3):375-401
The objective of this paper is to determine the optimum inventory policy for a multi-product periodic review dynamic inventory system. At the beginning of each period two decisions are made for each product. How much to “normal order” with a lead time of λn periods and how much to “emergency order” with a lead time of λe periods, where λe = λn - 1. It is assumed that the emergency ordering costs are higher than the normal ordering costs. The demands for each product in successive periods are assumed to form a sequence of independent identically distributed random variables with known densities. Demands for individual products within a period are assumed to be non-negative, but they need not be independent. Whenever demand exceeds inventory their difference is backlogged rather than lost. The ordering decisions are based on certain costs and two revenue functions. Namely, the procurement costs which are assumed to be linear for both methods of ordering, convex holding and penalty costs, concave salvage gain functions, and linear credit functions. There is a restriction on the total amount that can be emergency ordered for all products. The optimal ordering policy is determined for the one and N-period models. 相似文献
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The optimization framework for optimal sensor placement for underwater threat detection has been developed. It considers single‐period and multiperiod detection models, each of which includes two components: detection algorithm and optimization problem for sensor placement. The detection algorithms for single‐period and multiperiod models are based on likelihood ratio and sequential testing, respectively. For the both models, the optimization problems use the principle of superadditive coverage, which is closely related to energy‐based and information‐based approaches. An algorithm for quasi‐regular sensor placement approximating solutions to the optimization problems has been developed based on corresponding continuous relaxations and a criterion for its applicability has been obtained. Numerical experiments have demonstrated that the algorithm consistently outperforms existing optimization techniques for optimal sensor placement.© 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008 相似文献