检索结果-南通市图书馆

Activation Distance and Capacity Analysis for Ambient Backscatter Communications with Sensitivity Constraint and Beamforming

在线全文

学校读者我要写书评

暂无评论

China Communications 2024年第11期21卷 257-266页

作者： Mu Yunping Fan Dian Wang Gongpu Xu Yongjun Kuang Lei engineering Research center of Network Management Technology for High Speed Railway of Ministry of Education School of Computer and Information TechnologyBeijing Jiaotong UniversityBeijing 100044China China Academy of information and Communications Technology Beijing 100191China School of Communication and information engineering Chongqing University of Posts and TelemcommunicationsChongqing 400065China Shanghai Key Laboratory of Multidimensional information Processing Engineering Center of SHMEC for Space Information and GNSSSchool of Information Science and TechnologyEast China Normal UniversityShanghai 200241China

Circuit sensitivity of sensors or tags without battery is one practical constraint for ambient backscatter communication *** letter considers using beamforming to reduce the sensitivity constraint and evaluates the corresponding performance in terms of the tag activation distance and the system ***,we derive the activation probabilities of the tag in the case of single-antenna and multi-antenna ***,we obtain the capacity expressions for the ambient backscatter communication system with beamforming and illustrate the power allocation that maximizes the system capacity when the tag is ***,simulation results are provided to corroborate our proposed studies.

关键词： activation distance ambient backscatter communications beamforming channel capacity power allocation sensitivity

Multi-antenna synchronized global navigation satellite system receiver and its advantages in high-precision positioning applications

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2016年第4期10卷 772-783页

作者： Danan DONG Wen CHEN Miaomiao CAI Feng ZHOU Minghua WANG Chao YU Zhengqi ZHENG Yuanfei WANG engineering center of shmec for space information and gnss East China Normal University Shanghai 200241 China Shanghai Key Laboratory of Multidimensional information Processing East China Normal University Shanghai 200241 China Key Laboratory of Geographic information Science Ministry of Education East China Normal University Shanghai 200241 China College of Surveying and Geo-informatics Tongji University Shanghai 200092 China

The multi-antenna synchronized global navi- gation satellite system receiver is a high precision, low cost, and widely used emerging receiver. Using this type of receiver, the satellite and receiver clock errors can be eliminated simultaneously by forming between antenna single-differences, which is equivalent to the conventional double-difference model. However, current multi-antenna synchronized global navigation satellite system receiver products have not fully realized their potential to achieve better accuracy, efficiency, and broader applications. This paper introduces the conceptual design and derivable products of multi-antenna synchronized global navigation satellite system receivers involving the aspects of attitude determination, multipath effect mitigation, phase center variation correction, and ground-based carrier phase wind- up calibration. Through case studies, the advantages of multi-antenna synchronized global navigation satellite system receivers in high-precision positioning applications are demonstrated.

关键词： multi-antenna synchronized global navigationsatellite system receiver high-precision positioning attitudedetermination multipath effect mitigation phase centervariation correction ground-based carrier phase wind-upcalibration

Sub-Nyquist radar receiver based on photonics-assisted compressed sensing and cascaded dictionaries

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2024年第1期22卷 159-163页

作者：刘诗扬陈阳 Shanghai Key Laboratory of Multidimensional information Processing East China Normal UniversityShanghai 200241China engineering center of shmec for space information and gnss East China Normal UniversityShanghai 200241China

A sub-Nyquist radar receiver based on photonics-assisted compressed sensing is *** dictionaries are applied to extract the delay and the Doppler frequency of the echo signals,which do not need to accumulate multiple echo periods and can achieve better Doppler *** experiment is *** echoes with different delays and Doppler frequencies are undersampled and successfully reconstructed to obtain the delay and Doppler information of the *** results show that the average reconstruction error of the Doppler frequency is 5.33 kHz using an 8-μs radar signal under the compression ratio of *** proposed method provides a promising solution for the sub-Nyquist radar receiver.

关键词： compressed sensing dictionary learning sub-Nyquist radar microwave photonics Doppler frequency

A public Cloud-based China's Landslide Inventory Database(Cs LID): development, zone, and spatiotemporal analysis for significant historical events, 1949-2011

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2016年第7期13卷 1275-1285页

作者： LI Wei-yue LIU Chun HONG Yang ZHANG Xin-hua WAN Zhan-ming Manabendra SAHARIA SUN Wei-wei YAO Dong-jing CHEN Wen CHEN Sheng YANG Xiu-qin YUE Jing Institute of Urban Study Shanghai Normal University center for Spatial information Science and Sustainable Development Applications Tongji University College of Surveying and Geo-Informatics Tongji University School of Civil engineering and Environmental Sciences University of Oklahoma Advanced Radar Research center University of Oklahoma State Key Laboratory of Hydraulics and Mountain River engineering Sichuan University College of Architectural engineering Civil Engineering and Environment Ningbo University Department of Geography Shanghai Normal University engineering center of shmec for space information and gnss East China Normal University Applied Hydrometeorological Research Institute Nanjing University of Information Science & Technology Department of Stomatology Shanghai Tenth People’s Hospital of Tongji University

Landslide inventory plays an important role in recording landslide events and showing their temporal-spatial distribution. This paper describes the development, visualization, and analysis of a China's Landslide Inventory Database(Cs LID) by utilizing Google's public cloud computing platform. Firstly, Cs LID(Landslide Inventory Database) compiles a total of 1221 historical landslide events spanning the years 1949-2011 from relevant data sources. Secondly, the Cs LID is further broken down into six zones for characterizing landslide cause-effect, spatiotemporal distribution, fatalities, and socioeconomic impacts based on the geological environment and terrain. The results show that among all the six zones, zone V, located in Qinba and Southwest Mountainous Area is the most active landslide hotspot with the highest landslide hazard in China. Additionally, the Google public cloud computing platform enables the Cs LID to be easily accessible, visually interactive, and with the capability of allowing new data input to dynamically augment the database. This work developed a cyber-landslide inventory and used it to analyze the landslide temporal-spatial distribution in China.

关键词： Landslide Inventory Zone Distribution Cloud computing

PCA-U-Net based breast cancer nest segmentation from microarray(jj)hyperspectral images

在线全文

学校读者我要写书评

暂无评论

Fundamental Research 2021年第5期1卷 631-640页

作者： Jiansheng Wang Yan Wang Xiang Tao Qingli Li Li Sun Jiangang Chen Mei Zhou Menghan Hu Xiufeng Zhou Shanghai Key Laboratory of Multidimensional information Processing East China Normal University Shanghai 200241China engineering center of shmec for space information and gnss Shanghai 200241China Obstetrics&Gynecology Hospital of Fudan University Shanghai 200011China engineering Research center of Nanophotonics&Advanced Instrument Ministry of EducationEast China Normal UniversityShanghai 200241China Dmetrix Ltd.Co. SuzhouJiangsu 210000China

The incidence of breast cancer is tending younger globally,and tumor development,clinical treatment,and prognosis are largely influenced by histopathological *** diagnosed patients,the distinction between the cancer nests and normal tissue is the basis of breast cancer *** hyperspectral imaging technology has shown its potential in auxiliary pathological examinations due to the superior imaging modality and data *** paper presents a method for cancer nest segmentation from hyperspectral images of breast cancer tissue microarray *** scheme combines the strengths of the U-Net neural network and unsupervised principal component analysis,which reduces the amount of calculation and improves the recognition *** experimental accuracy of cancer nest segmentation reaches 87.14%.Furthermore,a set of quantitative pathological characteristic parameters reflects the degree of breast cancer lesions from multiple angles,providing a relatively comprehensive reference for the pathologist’s ***-depth exploration of the combined development of deep learning and microscopic hyperspectral imaging technology is worthy to promote efficient diagnosis of breast tumors and concern for human health.

关键词： Microscopic hyperspectral imaging Breast cancer Tissue microarrays Deep learning

Role,path,and vision of“5G+BDS/gnss”

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Satellite Navigation 2020年第1期1卷 257-264页

作者： Jingnan Liu Kefu Gao Wenfei Guo Jingsong Cui Chi Guo Research center of gnss Wuhan UniversityWuhan 430079China School of Cyber Science and engineering Wuhan UniversityWuhan 430072China

Communication,positioning,navigation,and decision-making abilities have evolved into Positioning,Navigation,and Timing(PNT)intelligence during the long process of human migration and hence promoted human *** article defines intelligence and smartness from the perspective of biological *** requirements as a result of the development of communication,navigation,time service,and decision making are identified in this *** article points out that there are many radio PNT service methods,such as 5G,the new-generation high-speed communication networks and the low-latency and ubiquitous mobile communication networks as well as Global Navigation Satellite System(gnss),but the integrated application is especially important in providing technical support for the adjustment and control of the physical world by intelligent sensing,cognition,decision-making,and precise *** fusion of 5G and gnss[including BeiDou Navigation Satellite System(BDS)]information with the corresponding equipment can be embedded into a machine to make it ***,the fused information of 5G and gnss together with the environment information may extend human perception and physical world control ability in terms of time and space *** will help to develop critical information infrastructure in the age of intelligence,which will also extend the definition of artificial ***,the“5G+BDS/gnss”fusion path is analyzed explicitly herein in terms of realization methods,information processing,and new application *** the whole,the application of“5G+BDS/gnss+satellite-based communication”as a critical infrastructure for land,sea,air,space and network spatiotemporal control rights is proposed.

关键词： 5G BDS/gnss Ubiquitous network Natural intelligence PNT intelligence

Study on systematic errors of BDS‑3 broadcast ephemeris and their effects with Helmert transformation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Satellite Navigation 2023年第3期4卷 153-166页

作者： Min Li Jiangnan Zhang Guo Chen Liang Chen Qile Zhao gnss Research center Wuhan UniversityNo.129 Luoyu RoadWuhan 430079China School of Geodesy and Geomatics Wuhan UniversityNo.129 Luoyu RoadWuhan 430079China School of Electronic and information engineering Beihang UniversityBeijing 100191China

Previous studies have not evaluated the systematic errors implied in the third generation of BeiDou-3 Navigation Satellite System(BDS-3)broadcast *** this paper we evaluate the systematic pattern described by the Helmert transformation parameters,including translations,rotations,and ***-3 broadcast and precise ephemerides from December 2019 to 2022 are collected,and the characteristics of the transformation parameters as well as their effects on the signal in space error are *** annual variation in the z-translation is obtained,and the similar amplitudes of 5.5 cm and phases of approximate 300 days are obtained for different *** the rotation parameters are considered in the orbit comparison,the Root Mean Square(RMS)errors of the along-and cross-track orbital differences decrease from 29.1 to 12.5 cm and from 30.6 to 9.2 cm,respectively,because the three rotation parameters compensate for the majority of the errors in the BDS-3 broadcast ***,the high correlations in the obtained rotation parameters among the three orbital planes suggest that the orientation of the BDS-3 broadcast ephemeris is influenced by common model errors,i.e.,uncertainty of Earth Rotation Parameters(ERPs).Further research is required because an offset of 1.5×10^(–9)for the scale parameter is observed.A degraded User Range Error(URE)for epochs of up to 84%is attained when the systematic pattern is considered,though the impact of the systematic pattern indicated by the z-translation and rotation parameters on the URE is less than 5.0 *** the refinement of the ERPs implemented in the new generation of broadcast ephemeris,we anticipate that the broadcast ephemeris performance of BDS-3 will be improved.

关键词： Broadcast ephemeris BDS-3 Helmert transformation Transformation parameters Correlation coefficient URE

Evaluation of gnss Signal-in-space Continuity:A Weibull-Distribution-Based Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2018年第3期27卷 634-640页

作者： LI Rui ZHENG Shuaiyong WANG Zhipeng TANG Yang SUN Si HUANG Zhigang School of Electronic and information engineering Beihang University Collaborative Innovation center of Geospatial Technology

Signal-in-space(SIS) continuity is an important performance index of Global navigation satellite system(gnss). However, the studies on the continuity of gnss SIS are limited both at home and abroad, and are mainly based on the exponential distribution method. We first employ this method to analyze SIS failures of GPS and BDS, finding that this method is not flexile when describing the characteristic of gnss SIS failures and the fitting characteristic of this method is not well. Therefore, we propose a method based on Weibull distribution to evaluate the performance of gnss SIS continuity. Our method is compared with the models of exponential distribution, normal distribution, and Gamma distribution regarding the fitting characteristics of the interruption time interval of GPS SIS, the critical parameter of continuity. Results show that the fitting characteristic of the Weibull-distributionbased method is the best and can be used in various forms to describe reliability problem. Then our method is used to evalute the SIS continuity of BDS and GLONASS and its effectiveness and rationality are validated again. The contributions of our study lie in the development of a practical method for evaluating gnss SIS continuity and a reference for gnss performance.

关键词： gnss SIS continuity Evaluation Exponential distribution Weibull distribution

GSTAR:an innovative software platform for processing space geodetic data at the observation level

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Satellite Navigation 2023年第3期4卷 122-141页

作者： Chuang Shi Shiwei Guo Lei Fan Shengfeng Gu Xinqi Fang Linghao Zhou Tao Zhang Zhen Li Min Li Wenwen Li Cheng Wang Yidong Lou Key Laboratory of Navigation and Communication Fusion Technology Ministry of Industry and Information Technology37 Xueyuan RoadBeijing 100191China School of Electronic and information engineering Beihang University37 Xueyuan RoadBeijing 100191China Research Institute for Frontier Science Beihang University37 Xueyuan RoadBeijing 100191China gnss Research center Wuhan University129 Luoyu RoadWuhan 430079China

To meet the demands for the data combination with multiple space geodetic techniques at the observation level,we developed a new software platform with high extensibility and computation efficiency,named space Geodetic SpatioTemporal data Analysis and Research software(GSTAR).Most of the modules in the GSTAR are coded in C++with object-oriented *** layered modular theory is adopted for the design of the software,and the antenna-based data architecture is proposed for users to construct personalized geodetic application scenarios *** initial performance of the GSTAR software is evaluated by processing the Global Navigation Satellite System(gnss)data collected from 315 globally distributed stations over two and a half *** accuracy of gnss-based geodetic products is evaluated by comparing them with those released by International gnss Service(IGS)Analysis centers(AC).Taking the products released by European space Agency(ESA)as reference,the Three-Dimension(3D)Root-Mean-Squares(RMS)of the orbit differences are 2.7/6.7/3.3/7.7/21.0 cm and the STandard Deviations(STD)of the clock differences are 19/48/16/32/25 ps for Global Positioning System(GPS),GLObal NAvigation Satellite System(GLONASS),Galileo navigation satellite system(Galileo),BeiDou Navigation Satellite System(BDS),Medium Earth Orbit(MEO),and BDS Inclined Geo-Synchronous Orbit(IGSO)satellites,*** mean values of the X and Y components of the polar coordinate and the Length of Day(LOD)with respect to the International Earth Rotation and Reference Systems Service(IERS)14 C04 products are-17.6 microarc-second(μas),9.2μas,and 14.0μs/*** to the IGS daily solution,the RMSs of the site position differences in the north/east/up direction are 1.6/1.5/3.9,3.8/2.4/7.6,2.5/2.4/7.9 and 2.7/2.3/7.4 mm for GPS-only,GLONASS-only,Galileo-only,and BDS-only solution,*** RMSs of the differences of the tropospheric Zenith Path Delay(ZPD),the north gradients,and the east gradien

关键词： GSTAR gnss BDS LEO Precise orbit determination Precise clock estimation Earth rotation parameter Tropospheric zenith path delay Geocenter motion Rapid data processing