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固定翼无人机视觉着降引导的合作信标设计方法 被引量:1
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作者 姚顺 程咏梅 +4 位作者 刘慧霞 肖佳伟 田朝旭 代力 杨速 《光学学报》 EI CAS CSCD 北大核心 2019年第3期267-273,共7页
基于透视模型原理,提出了固定翼无人机视觉着降引导的合作信标设计方法。通过信标成像对引导精度的敏感性进行分析,得到了信标特征点间最小距离的设计方法。在无人机由远及近接近信标的过程中,进行视场边界的迭代计算,给出了特征点布置... 基于透视模型原理,提出了固定翼无人机视觉着降引导的合作信标设计方法。通过信标成像对引导精度的敏感性进行分析,得到了信标特征点间最小距离的设计方法。在无人机由远及近接近信标的过程中,进行视场边界的迭代计算,给出了特征点布置范围的设计方法。搭建了OpenGL视景仿真系统,在国际民航组织规定的二级引导精度及多种无人机飞行位姿条件下,进行了图像敏感性及信标捕获情况分析。测量结果表明,所提方法可保证合作信标设计满足图像敏感性要求,且该信标始终可以被完整捕获。 展开更多
关键词 机器视觉 成像分析 信标设计 视觉导航
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X频段信标机的设计与实现 被引量:2
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作者 梁盛 潘高峰 +1 位作者 薛军 谢勇 《电讯技术》 北大核心 2017年第9期1088-1091,共4页
为满足船载X频段测控设备信道相位修正和伺服性能检查的需要,设计并研制了一款X频段信标机。首先,选用HMC765LP6CE芯片,利用频率合成技术设计了信源并通过通用串行总线(USB)实现了发射频率用户自定义;其次,针对安装平台面积小的限制,基... 为满足船载X频段测控设备信道相位修正和伺服性能检查的需要,设计并研制了一款X频段信标机。首先,选用HMC765LP6CE芯片,利用频率合成技术设计了信源并通过通用串行总线(USB)实现了发射频率用户自定义;其次,针对安装平台面积小的限制,基于高频结构仿真器(HFSS)设计了高次模微带天线并完成了仿真分析和指标优化;最后,完成了X频段信标机的工程实现并给出了硬件电路结构和软件程序设计方法。经测试,该信标机锁相效果良好,控制简便,性能可靠,满足用户使用要求。 展开更多
关键词 X频段测控设备 信标设计 直接频率合成 微带天线
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基于两路GPS信息接收和切换的无线信标机设计 被引量:1
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作者 郑俊华 谭秋林 秦小龙 《电子器件》 CAS 北大核心 2015年第4期863-867,共5页
通过对目前信标机的应用范围及国内外的发展状况进行研究,设计了一种基于两路GPS信息接收和切换的无线信标机。控制电路采用C8051F040单片机作为主控芯片,控制两路GPS模块的切换从而增加无线信标机的工作时间,提高定位精度并降低功耗。... 通过对目前信标机的应用范围及国内外的发展状况进行研究,设计了一种基于两路GPS信息接收和切换的无线信标机。控制电路采用C8051F040单片机作为主控芯片,控制两路GPS模块的切换从而增加无线信标机的工作时间,提高定位精度并降低功耗。实验测得UTC时间为11:37:30,北纬38.013 6°,东经112.446°,海拔高度为815.9 m。多次测量结果表明,该系统能实现定位数据的接收与转发并将定位信息通过上位机进行显示。 展开更多
关键词 电路与系统 信标设计 无线通信 两路GPS定位 低功耗
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Microphone Array Speech Enhancement Based on Tensor Filtering Methods 被引量:3
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作者 jing wang xiang xie jingming kuang 《China Communications》 SCIE CSCD 2018年第4期141-152,共12页
This paper proposes a novel microphone array speech denoising scheme based on tensor filtering methods including truncated HOSVD(High-Order Singular Value Decomposition), low rank tensor approximation and multi-mode W... This paper proposes a novel microphone array speech denoising scheme based on tensor filtering methods including truncated HOSVD(High-Order Singular Value Decomposition), low rank tensor approximation and multi-mode Wiener filtering. Microphone array speech signal is represented in three-order tensor space with channel, time, and spectrum modes and then tensor filtering model can be designed to process the multiway array data. As to the first method, noise can be reduced through the truncated HOSVD which is a simple scheme in tensor processing. It is more accurate to find the lower-rank approximation of the three-order tensor with Tucker model. Then MDL(Minimum Description Length) criterion is used to estimate the optimal tensor rank in the second method. Further, multimode Wiener filtering approach upon tensor analysis can be considered as the spanning of one-mode wiener filtering. How to take advantages of tensor model to obtain a set of filters is the heart of the novel scheme. The performances of the proposed three approaches are evaluated with objective indexes and listening quality test. The experimental results indicate that the proposed tenor filtering methods have potential ability of retrieving the target signal from noisy microphone array signal and the multi-mode Wiener filtering method provides the best denoising results among the three ones. 展开更多
关键词 speech denoising microphone ar-my tensor filtering truncated HOSVD low rankapproximation multi-mode Wiener filtering
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Determining the approach speed envelope of carrier aircraft 被引量:3
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作者 Geng Jianzhong Yao Hailin Duan Zhuoyi 《Engineering Sciences》 EI 2013年第6期19-23,31,共6页
Many factors,such as deck motion and air wave,influence the determination of the approach speed which has an important effect on landing safety. Until recently,there are no design criteria about approach speed of carr... Many factors,such as deck motion and air wave,influence the determination of the approach speed which has an important effect on landing safety. Until recently,there are no design criteria about approach speed of carrier aircraft in the current standards and available publications. Therefore,the requirements of stall margin, longitudinal acceleration ability,altitude correction and field-of-view on approach speed were researched. Based on the flight dynamics model,the flight simulations were conducted to study the effect of the response time of engine,wave off requirements,elevator efficiency and deflection rate on the approach speed. The results presented that the approach longitudinal acceleration and altitude correction ability had crucial influence on the approach speed envelope of the aircraft. The limitations of the control requirements,field- of- view requirements and gear were also given through the simulation and analysis. Based on the above results,the approach speed envelope were determined. 展开更多
关键词 carrier aircraft approach speed altitude correction handling quality landing safety
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Impact of and adaptation strategies for sea-level rise on Yangtze River Delta 被引量:9
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作者 WANG Qiu-Shun PAN Cun-Hong ZHANG Guang-Zhi 《Advances in Climate Change Research》 SCIE CSCD 2018年第2期154-160,共7页
The Yangtze River Delta characterized by a dense population and a rapidly developing economy is highly vulnerable to sea-level rise. The data from the China Oceanic Information Network and the Zhejiang Provincial Hydr... The Yangtze River Delta characterized by a dense population and a rapidly developing economy is highly vulnerable to sea-level rise. The data from the China Oceanic Information Network and the Zhejiang Provincial Hydrology Bureau are used to analyze sea-level rise. The rate of sea-level rise in the delta was 2.4 mm per year in 1981-2015. The annual sea-level at Daishan, Dinghai, and Dongtou stations in the south wing of the delta were 4.3, 3.1, and 5 mm per year respectively over the same period. The 10-year averaged results at each station also indicate a perceptible trend of sea-level rise. Sea-level rise is contributed to a larger proportion of intensified erosion, ranging from 3% to 14% in the delta. Meanwhile, the 100-year return period of tidal level has decreased to the 50-year rank at Dongtou and Dinghai stations. Moreover, the arrival time of tidal bores at Yanguan is 4 min earlier under sea-level rise of 0.145 m than that of 0 m. The height of tidal bores and the velocities at the surface and bottom layers have an increase under sea-level rise. The maximum increases of high and low tide levels are 0.122 m and 0.016 m while the maximum increases of the velocities at the surface and bottom layers are 0.07 m s^- 1 and 0.05 m s ^-1, respectively. Sea-level rise will bring about the damage of seawall, thus the design standard of constructing seawalls should adopt a higher level to minimize the associated risks in the Yangtze River Delta and its south wing. 展开更多
关键词 Coastal erosion Sea-level rise Saltwater intrusion Tidal bore Yangtze River Delta Zhejiang province
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Route design and automatic check in electronic chart display and information system 被引量:2
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作者 ZHAOYu-xin TANGJi-qiang LIGang GAOChao 《Journal of Marine Science and Application》 2004年第1期33-36,共4页
For an electronic chart display and information system (ECDIS), the most important function is the route design. In this paper, a novel approach to developing ECDIS was given and then an effective method was proposed ... For an electronic chart display and information system (ECDIS), the most important function is the route design. In this paper, a novel approach to developing ECDIS was given and then an effective method was proposed for route design and automatic check. The mathematical model and logical relationship for coordinate transformation were also provided. They were adopted in ECDIS developing, which was based on the researeh of the Vxworks real-time operating system. The actual system application implies that the method is practical and can help navigation very well. 展开更多
关键词 ECDIS route design coordinate transform VXWORKS
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Analysis of the Importance of Several Aspects before the Purchase of a Wine Bottle for Comunidad Valenciana (Spain) Consumers
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《Journal of Agricultural Science and Technology(B)》 2012年第5期563-573,共11页
This paper analyses the importance of several aspects that consumers in the Comunidad Valenciana (Spain) take into account when getting a wine bottle from a shelf. These aspects are: the designation of origin, the ... This paper analyses the importance of several aspects that consumers in the Comunidad Valenciana (Spain) take into account when getting a wine bottle from a shelf. These aspects are: the designation of origin, the price, design and information on the label, design and information on the back label, the point of sale, the seller advice, friends and family recommendations. The information has been obtained through survey with 400 interviews throughout Comunidad Valenciana (Spain). These interviews were based on asking a questionnaire with closed questions. It has been seen how the most valuated aspect is the designation of origin. The second aspect in the rank is friends and family Recommendations. Price is the third most valuated aspect. The less valuated aspects are the seller advice and the point of sale. The design and information of the label is more valuated than the design and information of the back label. Results seem to show how consumers want to reduce risk before buying a wine bottle looking for aspect that they can rely on. They give more importance to family and friends recommendations than to the seller advice. 展开更多
关键词 CONSUMER PURCHASE LABEL wine bottle.
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A new design criterion and construction method for space-time trellis codes based on classification of error events
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作者 Qiang Yongquan(强永全) Wang Jiao Li Daoben 《High Technology Letters》 EI CAS 2005年第3期289-293,共5页
The known design criterions of Space-Time Trellis Codes (STFC) on slow Rayleigh fading channel are rank, determinant and trace criterion. These criterions are not advantageous not onlv in operation but also in perfo... The known design criterions of Space-Time Trellis Codes (STFC) on slow Rayleigh fading channel are rank, determinant and trace criterion. These criterions are not advantageous not onlv in operation but also in performance. With classifying the error events of STTC, a new criterion was presented on slow Rayleigh fading channels. Basod on the criterion, an effective and straighttbrward multi-step method is proposed to ennstruet codes with better performance. This method can reduce the computation of search to small enough. Simulation results show that the codes searched by computer have the same or even better performance than the repored codes. 展开更多
关键词 space-time trellis codes design criterion wireless communication
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Portable Distortion Degree of Measuring Apparatus
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作者 王鑫 吕常智 王德勇 《Journal of Measurement Science and Instrumentation》 CAS 2011年第1期78-80,共3页
Distortion is a technical indicator in the field of voice signal processing. The design is a portable distortion degree tester, based on Field-Progranmmble Gate Array (FleA, EP2C20) as the cote, using harmonic analy... Distortion is a technical indicator in the field of voice signal processing. The design is a portable distortion degree tester, based on Field-Progranmmble Gate Array (FleA, EP2C20) as the cote, using harmonic analysis method which better solve the distortion problem of acctwacy. It can achieve the signal transformation from the time-domain to the frequency-donkain, and is widely used for signal spectrum analysis. All the componets used in the design are low power, high perf-, low drift and industrial grade compionents. The reference voltage sources of ADC and DAC have identical performance of high stability, high precision. The dtr.k is the precise stable clock with FPGA temperature compensation. This project can get the cost-effective, high-precision, low power and portable design goals. 展开更多
关键词 distortion degree FPGA measuring apparatus
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