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高速旋转目标旋转速度估计方法 被引量:6
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作者 胡杰民 付耀文 +1 位作者 胡志刚 黎湘 《电子与信息学报》 EI CSCD 北大核心 2009年第9期2069-2073,共5页
旋转速度估计是高速旋转目标成像的基础,论文提出一种新的旋转速度估计方法,该算法基于旋转目标在距离时间域所具有的特性,在利用傅里叶变换粗略估计旋转速度的基础上,利用计算图像熵的方法在特定范围内对角速度估计值进行调整,以获得... 旋转速度估计是高速旋转目标成像的基础,论文提出一种新的旋转速度估计方法,该算法基于旋转目标在距离时间域所具有的特性,在利用傅里叶变换粗略估计旋转速度的基础上,利用计算图像熵的方法在特定范围内对角速度估计值进行调整,以获得很高的估计精度。该方法直接计算整幅图像的熵值,从而不依赖单个的散射点。使用仿真数据演示了算法的性能,证明了算法的有效性。 展开更多
关键词 逆合成孔径雷达 转动目标 旋转速度估计 离散傅里叶变换
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空间目标双基地ISAR越多普勒单元徙动校正算法 被引量:2
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作者 郭宝锋 尚朝轩 +2 位作者 王昕 马俊涛 董健 《通信学报》 EI CSCD 北大核心 2014年第9期197-206,共10页
针对双基地逆合成孔径雷达(ISAR)的越多普勒单元徙动问题,以转台模型为研究对象,分别从回波信号模型和散射点相对收发双站速度变化2个角度分析了越多普勒单元徙动的产生机理,并提出了基于距离单元相位补偿的多普勒徙动校正算法。该算法... 针对双基地逆合成孔径雷达(ISAR)的越多普勒单元徙动问题,以转台模型为研究对象,分别从回波信号模型和散射点相对收发双站速度变化2个角度分析了越多普勒单元徙动的产生机理,并提出了基于距离单元相位补偿的多普勒徙动校正算法。该算法首先由双基地雷达与目标的几何关系估计出其等效旋转速度,然后通过等分观测期间的目标回波获取2幅不同观测视角的ISAR图像,依据图像旋转相关最大准则估计出图像的等效旋转中心,实现一维距离像的定标,最后对每个距离单元进行相位补偿,完成越多普勒单元徙动的校正。仿真实验表明,算法能有效解决双基地ISAR越多普勒徙动问题,提高ISAR成像质量。 展开更多
关键词 双基地 逆合成孔径雷达 越多普勒单元徙动 等效旋转速度估计 等效旋转中心估计
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Estimations of the Maximum Tangential Velocity V_(θm) in the Vortex Core Region and also the Mean Rotational Velocity V_(oi) near the Concave Wall Surface in the Returned Flow Type Cyclone Dust Collector
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作者 Akira Ogawa 《Journal of Thermal Science》 SCIE EI CAS CSCD 2010年第6期553-560,共8页
There are many types of cyclone dust collectors for separating the fine solid and dust particles from gases in the various industries and also in the home used purposes. For estimating the power loss and the collectio... There are many types of cyclone dust collectors for separating the fine solid and dust particles from gases in the various industries and also in the home used purposes. For estimating the power loss and the collection efficiency, one of the most important factors is the maximum tangential velocity V0m in the vortex core region in the cyclone body. In order to determine V0~ by the simple method, it is useful to apply the mechanical balance of the angular momentum fluxes under the assumption of Ogawa combined vortex model which is composed of the quasi-forced vortex in the vortex core region and also the quasi-free vortex surrounded the vortex core region and also under the assumption of the introduction of equivalent length Heq corresponding to the cone spaces of the cyclone body and the dust bunker. On the other hand, the mean rotational velocity Voi near the concave wall surface is also estimated by the mechanical balance of angular momentum fluxes with the moment of viscous friction force. For confirming the general applications of the obtained equations, the returned flow types cyclones changed the throat diameter D3 are designed. The material of the cyclone is the transparent acrylic resin. Therefore the inner surface of the cyclone body can be regarded as smooth surface. The comparisons of the measured velocities V~ and Voi by a cylindrical Pitot tube are shown in good agreement with those of the proposed equations. The above stated results are described in detail. 展开更多
关键词 Cyclone Dust Collector Maximum Tangential Velocity Mean Rotational Velocity Angular Momentum Flux Equivalent Length Surface Frictional Force Ogawa Combined Vortex Model Reynolds Number.
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