检索结果-内蒙古大学图书馆

2024 4th International Conference on Mechatronics technology and Aerospace engineering, ICMTAE 2024

作者： Li, Keman Shu, Leizheng Zhang, Wei University of Chinese Academy of Sciences Beijing100049 China Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing100094 China

This study conducts simulation research on the performance of utilizing weak GNSS signals for autonomous orbit determination of Low Lunar Orbit (LLO) spacecraft. The models of orbits, clocks, and measurements are derived and the autonomous orbit determination performance is accessed by Monte-Carlo simulations. The results show that the position estimation accuracy of an LLO spacecraft at a height of 100 km can reach 40 m by using a 15 dB gain antenna paired with a 15 dB-Hz high-sensitivity receiver. The orbit determination accuracy can reach approximately 23 m with a high-precision lunar gravity field model configured in the filter, which demonstrates the application prospects in both real-time and post-processing orbit determination of lunar orbit spacecraft. © 2025 Institute of Physics Publishing. All rights reserved.

关键词： Orbits

来源：评论

学校读者我要写书评

暂无评论

Containerless electrostatic levitation technology matched between the Chinese space station and ground: A comparative study and analysis of space-ground experiment 3

Containerless electrostatic levitation technology matched be...

引用

2024 3rd International Conference on Aerospace and Control engineering, ICoACE 2024

作者： Fei, Haoyi Yu, Jianding Zhong, Hongen University of Chinese Academy of Sciences Beijing100049 China Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing100094 China

This paper presents the progress of containerless electrostatic levitation experiments conducted on the Chinese space Station, alongside corresponding ground-based matching experiments. In space, the primary challenge lies in control issues. Due to the microgravity environment and the constraints of the space station, such as the electrostatic levitation furnace’s volume and automation, several innovative strategies have been implemented, including the use of optimization algorithms to bypass the sample charge inversion point. On the ground, both levitation and control challenges must be addressed. To address the issue of charge reversal points during levitation, an innovative method of preheating the sample has been adopted. This approach involves preheating the sample to a specific state before levitation, thereby mitigating the impact of the charge reversal point during the control process and ensuring the smooth execution of the experiment. This innovation offers a novel solution for ground-based electrostatic levitation experiments. Through a detailed analysis of the space and ground experimental conditions, the study explores the similarities and differences between the space-based and ground-based electrostatic levitation technologies. The findings aim to optimize ground-based matching experiments and provide valuable insights for future improvements to the electrostatic levitation furnace aboard the Chinese space Station. © 2025 Institute of Physics Publishing. All rights reserved.

关键词： space stations

来源：评论

学校读者我要写书评

暂无评论

Optical Wireless Link Enhanced Wireless Mesh Networks with Bottleneck Connections

Optical Wireless Link Enhanced Wireless Mesh Networks with B...

引用

2024 Advanced Fiber Laser Conference, AFL 2024

作者： Qi, Wenchao He, Yuna Shen, Pengfei Lu, Lu Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing100094 China University of Chinese Academy of Sciences Beijing100049 China

ISBN: (数字)9781510688889

ISBN: (纸本)9781510688872

Bottleneck link connections may seriously decrease the overall system throughput of wireless mesh networks (WMNs) in which the user nodes are interconnected in a distributed way. With the increasing demands for higher data rates among the WMN user nodes, traditional mesh network using radio frequencies (RF) can easily break down if one or more critical links are selected to serve many parallel traffics or overwhelmed by other co-channel wireless interferences. These bottleneck links are shown to introduce severe end-to-end delays, and hence become a big barrier for the real deployments of WMN. To tackle the bottleneck link problem in RF-based WMNs, we propose a novel system architecture by introducing another dimension of transmissions. Specifically, we establish optical wireless communications (OWC) links on top of the original bottleneck links whose negative effects on the system throughput are mitigated, and we call the system O-WMN which is designed to make the best of both RF and OWC links’ superior properties. In O-WMN, the RF links are used to initialize the basic routing tables for each node using the optimized link state routing (OLSR) protocol. And then, the bottleneck links are identified and broadcasted to all nodes in O-WMN. After that, the OWC links are activated for the bottleneck links. However, since the OWC links are vulnerable to the line-of-sight (LoS) connections, some links might be blocked due to the next topology. To address the OWC link blockage issue in O-WMN, we further design a link selection method to leverage the routing tables, which ensures that OWC links are deployed in a proper way, such that the throughput of the whole network can be improved. Specifically, a new routing protocol named parallel OLSR (P-OLSR) is proposed, so that new OWC link based routing can offload traffics in the bottleneck RF links. To find an ideal route for O-WMN, a new link quality metric based on expected transmission count (ETX) is employed to determine ro

关键词： Wireless mesh networks (WMN)

来源：评论

学校读者我要写书评

暂无评论

Self-play training for general impulsive orbital game 3

Self-play training for general impulsive orbital game

引用

2024 3rd International Conference on Aerospace and Control engineering, ICoACE 2024

作者： Zhou, Rui Zhang, Hao Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing100094 China University of Chinese Academy of Sciences Beijing100049 China

In this paper, the decision and training architecture based on intelligent methods is provided for a more general impulsive orbital game problem. Then, the impulsive maneuver intervals are incorporated into the game action set and the reinforcement learning method is utilized to make decisions. Based on prioritized fictitious self-play, a method to rapidly generate an opponent population is proposed to train the agent to defeat opponents with various strategies. Finally, the evaluation matrix is decomposed by dimensionality reduction and the transitivity and cyclicity between strategies are analyzed, demonstrating that the agent can continuously improve strategy even in the face of an opponent population with increasingly rich strategies. © 2025 Institute of Physics Publishing. All rights reserved.

关键词： Dimensionality reduction

来源：评论

学校读者我要写书评

暂无评论

Study on the Performance of Supercapacitors Under Irradiation Environment 19th

Study on the Performance of Supercapacitors Under Irradiatio...

引用

19th Annual Conference of China Electrotechnical Society, ACCES 2024

作者： Li, Dunmin Liu, Yanmin Zhang, Jian Zhang, Jianquan Zhang, Zeming Zhang, Wen School of Aeronautics and Astronautics University of Chinese Academy of Sciences Beijing101400 China Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing100080 China Key Laboratory of Space Applications Space Application Engineering and Technology Center Chinese Academy of Sciences Beijing100080 China

ISBN: (纸本)9789819613823

Super capacitor is a new type of green energy storage device with high power density, long cycle life, fast charge and discharge speed, high reliability, green and environmental protection, etc. It has great application potential in aerospace and other fields. Electrode materials and electrolytes are the key to super capacitors, which determine the main performance indicators of the energy storage device. In the study of various performance parameter indicators of super capacitors, equivalent series internal resistance and capacitance are very important indicators to determine whether the super capacitor can work normally. In the national key R&D plan "Radiation-resistant Sic-based power electronic devices and their applications in aerospace power supply" project, the energy storage unit of the aerospace power supply adopts a super capacitor module. In order to explore the impact of space radiation on the super capacitor energy storage unit, an irradiation test was designed. The Co60γ radiation source was used to conduct different irradiation tests on the randomly selected super capacitors of the same batch. The capacitance and internal resistance of the super capacitor were tested before and after the test, and then the data were analyzed. The results show that after the irradiation test, the capacitance and resistance of the super capacitor changed, but they were still within the requirements of the specification and met the requirements of the energy storage unit. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Gamma rays

来源：评论

学校读者我要写书评

暂无评论

Few-shot skylight detection with StyleGAN2-ADA and YOLOv9-PSA 6

Few-shot skylight detection with StyleGAN2-ADA and YOLOv9-PS...

引用

6th International Conference on Geoscience and Remote Sensing Mapping, GRSM 2024

作者： Li, Lihong Mu, Lingli He, YuQing Li, Jiaxi Xian, Lina Zhang, Wei Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing100094 China Key Laboratory of Space Utilization Chinese Academy of Sciences Beijing100094 China School of Aeronautics and Astronautics University of Chinese Academy of Sciences Beijing100049 China

ISBN: (纸本)9781510688018

Skylights, as a unique and scarce type of pits on Mars, are significant for scientific research and engineering applications. Compared with visual interpretation to detect skylights, deep learning methods are more automatic and objective. However, existing deep-learning methods face low accuracy due to very few skylight samples and the model's inability to capture the subtle features that differentiate skylights from typical pits. To solve the problem, skylight samples generated with StyleGAN2-ADA network are used to expand the original dataset and not-skylight pits are used as negative samples for adversarial training. These improvements reduce the number of misidentified skylights to approximately 1.3% of the original. Furthermore, to enhance the feature extraction capability, we propose the YOLOv9-PSA model, leading to a 14.1% increase in precision. The results indicate that expanded dataset and the YOLOv9-PSA model significantly improve detection accuracy, with final metrics achieving a precision of 94.1%, a recall rate of 88.9%, and an F1 score of 91.4%. The method proposed in this paper provides a foundation for skylight detection of other celestial bodies. © 2025 SPIE.

关键词： Martian surface analysis

来源：评论

学校读者我要写书评

暂无评论

PatchTCN: Patch-Based Transformer Convolutional Network for Times Series Analysis 24

PatchTCN: Patch-Based Transformer Convolutional Network for ...

引用

Proceedings of the 2024 3rd International Symposium on Computing and Artificial Intelligence

作者： Jian Zhang Lili Guo Lei Song Song Gao Chuanzhu Hao Xuzhi Li Key Laboratory of Space Utilization Technology and Engineering Center for Space Utilization Chinese Academy of Sciences University of Chinese Academy of Sciences Beijing China Key Laboratory of Space Utilization Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing China College of Electrical Engineering Shandong Huayu University of Technology Shandong China

ISBN: (纸本)9798400710674

This study introduces a novel model for multivariate time series forecasting and imputation, called PatchTCN. This hybrid model combines the global and local processing capabilities of Transformer and Convolutional Neural Network(CNN), respectively. Developed from the PatchTST framework, which converts input time series data into a series of patches, our research addresses PatchTST's limitations in capturing intricate local dynamics and its fixed-length patch constraint. By integrating the innovative InterPatch-Conv and MSPatch-Conv modules, our model enhances local feature modeling and adapts to variable-length patches, providing a deeper understanding of time series data. Experimental results across various datasets have demonstrated that PatchTCN outperforms existing models in both forecasting and imputation tasks, proving its effectiveness in handling global dependencies and local temporal variations. This fusion of Transformer and CNN methodologies not only sets a new benchmark for time series analysis but also paves the way for further research into combining architectural strengths.

关键词： CNN

来源：评论

学校读者我要写书评

暂无评论

Performance Analysis of PPM-SNSPD System for Deep space Optical Communications

引用

IEEE Transactions on Communications 2025年

作者： Shi, Ziyuan Wu, Xiaowei Yang, Lei Zhan, Yueying Ng, Derrick Wing Kwan Wang, Qiang Key Laboratory of Space Utilization Technology and Engineering Center for Space Utilization Beijing100094 China University of New South Wales School of Electrical Engineering and Telecommunications SydneyNSW2025 Australia

The optical communication system using pulse position modulation (PPM) and superconducting nanowire single-photon detectors (SNSPDs) has attracted considerable attention for deep space applications as it enables high speed data transmission at extremely low average signal power. The deadtime of SNSPD is a critical factor in such systems because it primarily affects the signal detection efficiency. This becomes even more crucial in high-speed systems, where the deadtime can span several symbol periods. We employ the Markov chain model to characterize the high-speed PPM-SNSPD system and investigate its behavior. Analytical expressions for symbol transition probabilities are derived to characterize system-level metrics, including the symbol error rate and achievable code rate. Analysis shows that deadtime introduces memory to the PPM-SNSPD channel, resulting in channel asymmetry. Through experimental verification and simulations, we confirmed the effectiveness of our analysis. In addition, a set of new log-likelihood ratio (LLR) expressions is proposed based on the new model. Compared with the commonly used Poisson LLR expression, our proposed LLR expressions show more than 0.5 dB performance gain. © 2025 IEEE.

关键词： Pulse position modulation

来源：评论

学校读者我要写书评

暂无评论

Performance Analysis of RIS-Aided Hybrid RF-FSO Communications With Index Modulation

IEEE Photonics Journal

引用

IEEE Photonics Journal 2025年第3期17卷

作者： He, Yuna Qi, Wenchao Shen, Pengfei Lu, Lu Chinese Academy of Sciences Key Laboratory of Space Utilization Technology and Engineering Center for Space Utilization Beijing100094 China University of Chinese Academy of Sciences Beijing100049 China

This work investigates the performance of a hybrid communication system that integrates radio frequency (RF) and free-space optical (FSO) systems for backhaul networks. In this framework, both the RF and FSO links are enhanced by reconfigurable intelligent surfaces (RISs) and employ index modulation (IM) for link switching. The fading in the RF link is modeled using the Nakagami-m distribution, while the FSO link is affected by attenuation, turbulence, and pointing errors, with turbulence characterized by the Gamma-Gamma distribution. Link switching is performed through index modulation, where the selection of the transmission link conveys information bits. We derive exact closed-form expressions for the probability density function (PDF), cumulative distribution function (CDF), and moment-generating function (MGF) of the signal-to-noise ratio (SNR) for RIS-assisted FSO links. Utilizing these SNR statistics, we compute the outage probability (OP), average bit error rate (ABER), and ergodic capacity (EC) of the proposed hybrid RF/FSO system. In the numerical results, the performance of the proposed hybrid RF/FSO system is compared against other systems, including hybrid systems using index modulation without RISs, RIS-assisted FSO systems, and hybrid systems employing hard switching techniques. Finally, Monte Carlo simulations are carried out to validate the accuracy of the theoretical results. © 2009-2012 IEEE.

关键词： Distribution functions

来源：评论

学校读者我要写书评

暂无评论

3D Label Layout with Binocular Optimization 25

3D Label Layout with Binocular Optimization

引用

Companion Proceedings of the ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games

作者： Zijie Zheng Yu He Ge Yu Xi Xu University of Chinese Academy of Sciences Beijing China and Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing China Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing China

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：