检索结果-内蒙古大学图书馆

The International VLBI Service for Geodesy and Astrometry (IVS)(第八届国际大地测量和天体VLBI服务大会)

作者： Geshi TANG National Key Laboratory of Science and Technology on Aerospace Flight Dynamics/Beijing Aerospace Control Center

来源：评论

学校读者我要写书评

暂无评论

A new correlation algorithm of VLBI based on spectrum shift elimination

A new correlation algorithm of VLBI based on spectrum shift ...

引用

International Conference on Signal Processing Proceedings (ICSP)

作者： Songtao Han Geshi Tang National Key Laboratory of Science and Technology on Aerospace Flight Dynamics Beijing Aerospace Control Center

ISBN: (纸本)9781479921898

This paper presents a new algorithm of correlation processing in the domain VLBI(Very Long Baseline Interferometry). For VLBI tracking by cross-cooperation of multi-organizations, the problem of different sampling rate parameter may be encountered. The algorithm in this paper has the advantages of low computational burden and higher accuracy. Because both computational burden and signal-to-noise loss caused by resampling are avoided. For data processing of Venus Express(VEX) experiment, the accuracy of interferogram improved about 10 percent compared with resampling algorithm, and the efficiency improved 20 percent, which testified the effectiveness of our algorithm.

关键词： Abstracts Delays Quantization (signal) Vectors Noise Algorithm design and analysis Accuracy

来源：评论

学校读者我要写书评

暂无评论

Orbit Validation with satellite laser ranging data on GNSS satellite orbit

Orbit Validation with satellite laser ranging data on GNSS s...

引用

第五届中国卫星导航学术年会

作者： Xia Jinchao Tang Geshi Li Xie Cui Hongzheng Cao Jianfeng Song Baiyan State Key Laboratory of Science and Technology on Aerospace Flight Dynamics Beijing Aerospace Control Center China

GNSS satellite orbit precision is the foundation of any other kinds of related researches and applications. For GNSS satellites equipped with a laser reflector, which can both obtain high-precision laser ranges and ground GNSS stations radio tracking ranges, the orbits precision can be checked between the two kinds of observations. This paper studied the method to check GNSS satellite orbit using satellite laser ranging, and took SLR data of GPS36 on July 2013 as an example for direct verification. The results showed that, GPS36 satellite orbits and SLR observation were good consistent, with a mean residual about 5.5cm. This method of orbit comparison can be promoted to evaluate the accuracy of similar GNSS satellites, such as Beidou satellite system as an external orbit precision validation in the construction of our iGMAS centers.

关键词： iGMAS GNSS satellite laser ranging navigation and positioning orbit

来源：评论

学校读者我要写书评

暂无评论

Tracking Guidance Strategy for Low-thrust Transfer Trajectory Based on NMPC Theory

Tracking Guidance Strategy for Low-thrust Transfer Trajector...

引用

第26届中国控制与决策会议

作者： SHANG Hai-bin WANG Shuai JIN Ting HUANG Xiang-yu Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of EducationSchool of Aerospace EngineeringBeijing Institute of Technology Science and Technology on Space Intelligent Control Laboratory

A tracking guidance scheme based on nonlinear model predictive control is proposed for low-thrust transfer trajectory. According to the optimal nominal transfer trajectory, the NMPC is used to design the predictive model of perturbed orbit. Performance index of receding optimization is established, which can indicate the difference between the nominal trajectory and prediction trajectory. Taking the orbit state of nominal transfer trajectory as the initial value, the optimal control sequence is solved by the sequential quadratic programming algorithm. Meanwhile, in order to eliminate the predictive model error, the accuracy of the next control sequence is improved by the introduction of feedback compensation. Taking earth-mars low-thrust transfer as an example, numerical simulation is used to verify the efficiency of the proposed method.

关键词： low-thrust,tracking guidance,nonlinear model predictive control,numerical simulation

来源：评论

学校读者我要写书评

暂无评论

The combination of SfM and monocular SLAM

The combination of SfM and monocular SLAM

引用

第26届中国控制与决策会议

作者： Haoyin Zhou Tao Zhang Department of Automation School of Information Science and TechnologyTsinghua University National Key Laboratory of Integrated Flight Vehicle Control Technology Xian Flight Automatic Control Research Institute

To realize autonomous navigation with a regular camera in an unknown environment, there are mainly two types of approaches: SfM and monocular SLAM. They both have advantages and disadvantages. SfM is slow and cannot eliminate outliers, but it is able to provide 3D information from a series of images without any additional *** SLAM can hardly work unless the initial value is close to the real value, but it is fast and can handle outliers naturally. The combination approach proposed in this paper combines SfM and monocular SLAM. It uses SfM as a observer to linearize the observation function used in monocular SLAM, and uses the results of monocular SLAM to accelerate SfM. Outliers are pointed out by SfM and handled by monocular SLAM. Simulation and experiment results show that the proposed combination approach is feasible. The accuracy is improved compared with SfM and outliers can be eliminated.

关键词： structure from motion(SfM),monocular simultaneous localization and mapping(monocular SLAM),combination

来源：评论

学校读者我要写书评

暂无评论

Athermal scheme based on resonance splitting for silicon-on-insulator microring resonators

引用

Photonics Research 2014年第2期2卷 71-74页

作者： Qingzhong Deng Xinbai Li Zhiping Zhou Huaxiang Yi State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer SciencePeking UniversityBeijing 100871China Xi’an Flight Automatic Control Research Institute Aviation Industries of China(AVIC)Xi’an 710065China

A novel athermal scheme utilizing resonance splitting of a dual-ring structure is *** design and simulation are presented,and a proof of concept structure is optimized to demonstrate an athermal resonator with resonan... 详细信息

关键词： splitting scheme resonance

来源：评论

学校读者我要写书评

暂无评论

Tracking guidance strategy for low-thrust transfer trajectory based on NMPC theory

Tracking guidance strategy for low-thrust transfer trajector...

引用

Chinese control and Decision Conference, CCDC

作者： Hai-bin Shang Shuai Wang Ting Jin Xiang-yu Huang Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of Education School of Aerospace Engineering Beijing Institute of Technology 100081 China Science and Technology on Space Intelligent Control Laboratory Beijing 100190 China

关键词： Trajectory Optimization Predictive models Orbits Space vehicles Predictive control Accuracy

来源：评论

学校读者我要写书评

暂无评论

A Simulation Model for Airport Runway Capacity Estimation

A Simulation Model for Airport Runway Capacity Estimation

引用

17th International IEEE Conference on Intelligent Transportation Systems & The Asia-Pacific Council on Systems Engineering Conference 2014

作者： Xiang Zou Peng Cheng Nong Cheng National Key Laboratory of Civil Aircraft Flight Simulation Shanghaiand with the Department of AutomationTsinghua University Department of Automation Tsinghua UniversityBeijingChina Science and Technology of Aircraft Control Laboratory Flight Automatic Control Research Institute

This paper presents a simulation model applied for estimating the capacity of airport's runway *** from most analytical runway capacity estimation models which use mathematical formulas to compute capacity directly and some other programming-intensive simulation models,we utilize a sophisticated discrete event simulation software,Arena,to construct a runway capacity estimation *** model combines arrival's airside phase(final approach) and groundside phase(landing and taxiing) ***'s more,since we have considered several most significant phenomena with effect on the capacity in the model,such as fleet mix,performance,and location of exit way,it can be built into other relevant simulation models to serve as a virtual runway system with enough fidelity and *** the end of this paper,an example for hours' operation in Beijing Capital International Airport demonstrates the estimation made by our model is highly reliable.

关键词： A Simulation Model for Airport Runway Capacity Estimation Model

来源：评论

学校读者我要写书评

暂无评论

A probabilistic spectral graph matching algorithm for robust correspondence between lunar surface images

A probabilistic spectral graph matching algorithm for robust...

引用

World Congress on Intelligent control and Automation (WCICA)

作者： Xu Yang Chuan-Kai Liu Zhi-Yong Liu Hong Qiao Bao-Feng Wang Zi-Dong Wang State Key Laboratory of Management and Control for Complex Systems Chinese Academy of Sciences Beijing Aerospace Flight Control Center School of Information Science and Technology Donghua University

The correspondence between key points is an important problem in lunar surface image processing, and further lays the foundation for the navigation of a rover and the terrain reconstruction of the lunar surface. However, the problem is still challenging due to the existence of large scale and rotation transformations, reflected view of the same scenery, and different illumination conditions between acquired images as the lunar rover moves forward. Traditional appearance matching algorithms, like SIFT, often fail in handling the above situations. By utilizing the structural cues between points, in this paper we propose a probabilistic spectral graph matching method to tackle the point correspondence problem in lunar surface images acquired by Yutu lunar rover which has been recently transmitted to the moon by China's Chang'e-3 lunar probe. Compared with traditional methods, the proposed method has three advantages. First, the incorporation of the structural information makes the matching more robust with respect to geometric transformations and illumination changes. Second, the assignment between points is interpreted in a probabilistic manner, and thus the best assignments can be easily figured out by ranking the probabilities. Third, the optimization problem can be efficiently approximately solved by spectral decomposition. Simulations on real lunar surface images witness the effectiveness of the proposed method.

关键词： Moon Probabilistic logic Image edge detection Surface treatment Accuracy Optimization Robustness

来源：评论

学校读者我要写书评

暂无评论

Simple Precise Time Signal Delivery over Fiber Link Scheme

Simple Precise Time Signal Delivery over Fiber Link Scheme

引用

第五届中国卫星导航学术年会

作者： Yitang Dai Zhongle Wu Tianpeng Ren Feifei Yin Kun Xu Jintong Lin Geshi Tang State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Science and Technology on Aerospace Flight Dynamics Laboratory Beijing Aerospace Control Center

The capability of transferring time signal to remote locations with high stability and accuracy for synchronization is crucial for many important occasions,involving very long‐baseline interferometry,coherent radio telescope arrays,modern particle accelerator,and the Deep Space *** widely used satellite methods of time and frequency transfer are unable to preserve the stability delivered by modern timekeeping *** meet these high stability requirements,optical fiber link has been used to transfer frequency and time reference,which however still suffers from mechanical perturbation and temperature variation along the link and degrades the phase stability at the remote *** the past decade,researchers mainly focused on the frequency dissemination,and the transfer stability is now sufficient for most frequency ***,the time signal transfer stability is far below frequency reference,which is typically at the nanosecond accuracy *** propose and demonstrate a stable time signal delivery scheme over fiber link utilizing frequency stabilization *** the scheme,we utilizing the frequency reference to compensate the link‐length variation,and the total transfer delay is kept *** time signal is regenerated at the remote *** fiber link we used in this paper is 10‐km,and the long‐term fiber delay variation is more than 800 *** obtain a time deviation of 40 ps at 1‐s and falling to 2.3 ps at 1000‐s averaging time for time *** time delay resolution of scheme is 1 ps,and the compensation range is in direct proportion with the fiber *** proposed scheme shows a potential ability to precisely transfer time signal and frequency reference simultaneously,which is very suitable for long range time and frequency transfer.

关键词： Time and Frequency Delivery Fiber Link Time Deviation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：