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双星(站)时差频差无源定位误差分析 被引量:5
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作者 张政超 袁翔宇 +3 位作者 陆静 徐裴为 李文臣 李宏 《中国电子科学研究院学报》 北大核心 2016年第1期107-110,共4页
针对电子侦察卫星对地面固定辐射源进行无源定位问题,对站心坐标和大地直角坐标进行了相互转换,推导了基于双星(站)时差无源定位的方法,建立了定位方程组并指出解析方法;分析了基于双星(站)时差无源定位的误差和几何精度稀释。仿真结果... 针对电子侦察卫星对地面固定辐射源进行无源定位问题,对站心坐标和大地直角坐标进行了相互转换,推导了基于双星(站)时差无源定位的方法,建立了定位方程组并指出解析方法;分析了基于双星(站)时差无源定位的误差和几何精度稀释。仿真结果表明,定位精度与双星的时差、频差、自定位、速率等测量精度和双星的空间构型(连线长度、高度)及运行速率有关,频差测量精度比时差测量精度更敏感。 展开更多
关键词 双星(站)定位 时差频差联合 定位误差分析 几何精度稀释
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图形形状和空间位置知觉的ERP研究 被引量:4
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作者 饶恒毅 周天罡 +2 位作者 卓彦 范思陆 陈霖 《生物物理学报》 CAS CSCD 北大核心 2001年第3期487-494,共8页
研究图形形状和空间位置知觉任务与单纯图形形状知觉任务所诱发的ERP反应 ,探讨同时注意物体的两种不同特征时与仅注意其中一种特征时的ERP特征与差别。实验结果为 :(1)行为数据显示 ,两种任务的正确率没有显著差别 ,但形状和空间位置... 研究图形形状和空间位置知觉任务与单纯图形形状知觉任务所诱发的ERP反应 ,探讨同时注意物体的两种不同特征时与仅注意其中一种特征时的ERP特征与差别。实验结果为 :(1)行为数据显示 ,两种任务的正确率没有显著差别 ,但形状和空间位置知觉任务的反应时显著低于单纯形状知觉任务 ;(2)ERP数据显示 ,两种任务表现出非常相近的ERP波形特征 :在大脑后部区域微弱的P1成分 ,非常显著的N1成分 ,显著的P2 ,N2 ,P3成分 ;在大脑前部额区显著的P2成分。并且 ,与单纯形状知觉任务相比 ,图形形状和空间位置知觉任务表现枕颞区N2波幅的显著减弱 ,P3潜伏期的显著缩短 ,额区的P2波幅的显著减弱 ;(3)脑电地形图与高分辨率断层成象(LORETA)显示 ,两种任务的特征波N1成分均来源于双侧的枕颞皮层 ,表明两种任务均涉及到与物体形状识别相关的视皮层腹侧通路 ,而差别波dN2成分来源于左侧枕颞区 ,暗示特征加工的差异主要发生在左侧枕颞区。 展开更多
关键词 形状知觉 空间位置知觉 事件相关电位 源定位分析 ERP
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Entropy Analysis of NH_3/H_2O Absorption-Compression Heat Pump 被引量:1
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作者 龙臻 罗勇 +2 位作者 田永军 廉永旺 马伟斌 《Journal of Donghua University(English Edition)》 EI CAS 2012年第6期461-464,共4页
The absorption-compression heat pump (ACHP) has been considered as an effective approach to recover and utilize low-grade heat sources. In the present study, the first and second law thermodynamic analyses of the AC... The absorption-compression heat pump (ACHP) has been considered as an effective approach to recover and utilize low-grade heat sources. In the present study, the first and second law thermodynamic analyses of the ACHP with NH3/H20 as working fluid were performed. Thermodynamic properties of each point and heat transfer rate of each component in the cycle under basic operation conditions were calculated from the first law analysis. Following the second law of thermodynamics, the entropy generation of each component and the total entropy generation of the system were obtained. The effect~ of the heating temperature, heat source temperature, and compression ratio on the coefficient of performance (COP) and the total entropy generation ( STot ) of the system were examined. The results show that the increase in COP corresponds to a decrease in STot, and vice versa; besides, for certain operating conditions, an optimum compression ratio in the NH~/H20 ACHP exists. 展开更多
关键词 heat pump absorption-compression second law ofthermodynamics entropy generation
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Multiple moving sources passive location based on multiset canonical correlation analysis
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作者 禹华钢 Huang Gaoming Gao Jun 《High Technology Letters》 EI CAS 2013年第2期197-202,共6页
To solve the problem of multiple moving sources passive location, a novel blind source separa- tion (BSS) algorithm based on the muhiset canonical correlation analysis (MCCA) is presented by exploiting the differe... To solve the problem of multiple moving sources passive location, a novel blind source separa- tion (BSS) algorithm based on the muhiset canonical correlation analysis (MCCA) is presented by exploiting the different temporal structure of uncorrelated source signals first, and then on the basis of this algorithm, a novel multiple moving sources passive location method is proposed using time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements. The key technique of this location method is TDOA and FDOA joint estimation, which is based on BSS. By blindly separating mixed signals from multiple moving sources, the multiple sources location problem can be translated to each source location in turn, and the effect of interference and noise can also he removed. The simulation results illustrate that the performance of the MCCA algorithm is very good with relatively light computation burden, and the location algorithm is relatively simple and effective. 展开更多
关键词 multiset canonical correlation analysis (MCCA) blind source separation (BSS) time difference of arrival (TDOA) frequency difference of arrival (FDOA) passive location mul-tiple sources
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