Article
Engineering, Aerospace
Angel David Arcia Gil, Daniel Renwick, Chantal Cappelletti, Paul Blunt
Summary: Global Navigation Satellite Systems (GNSS) have been proven effective in providing positioning, navigation, and timing services in lunar missions, which presents an opportunity for the study of lunar GNSS constellation design requirements and performance. With the increasing number of moon missions, accurate and reliable navigation systems are crucial for the safety and success of future lunar exploration. Through multi-objective optimization, 12,000 unique constellation designs were generated and the top 10 constellations achieved a 44% improvement in Position Dilution of Precision (PDoP), meeting the performance requirements of planned lunar missions.
Review
Geosciences, Multidisciplinary
Yuanxi Yang, Xia Ren, Xiaolin Jia, Bijiao Sun
Summary: To ensure the safety of core infrastructure in terms of positioning, navigation, and timing (PNT), it is crucial to establish a secure PNT system using hybrid physical principles. This paper analyzes the augmentations of the BeiDou satellite system (BDS), including inter-satellite link augmentations, geostationary orbit (GEO) and inclined geostationary orbit (IGSO) satellites, and PNT services supported by low earth orbit (LEO) satellites. The comprehensive PNT infrastructure described in this paper, centered around BDS, covers deep space and deep ocean, incorporating deep space PNT constellation, sea-floor PNT sonar beacon network, and ground-based low frequency and very low frequency (VLF) long wave radio stations. Additionally, key technologies for resilient PNT application, intelligent PNT services, and integration of autonomous perception PNT information are discussed.
SCIENCE CHINA-EARTH SCIENCES
(2023)
Article
Computer Science, Information Systems
Pengfei Wang, Boya Di, Lingyang Song
Summary: This letter studies the design and performance analysis of an integrated satellite-terrestrial network for global seamless connectivity and high-rate backhaul transmission. Through a theoretical framework and mega-constellation design, the optimal number of satellites is proposed, and it is found that the even distribution of terrestrial infrastructures affects mega-constellation design.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2022)
Article
Engineering, Aerospace
Yifei Jiang, Wanxia He, Wenzheng Liu, Shufan Wu, Xiao Wei, Qiankun Mo
Summary: This paper proposes a B5G NTN-based data collection system using low-earth orbit satellites as a CubeSat constellation for global coverage and the 5G terrestrial network as the data bearer network. The system also incorporates a traffic load balance strategy for optimization. The design was verified through a series of experiments.
Article
Environmental Sciences
Lizhao Wang, Barton A. Forman, Edward Kim
Summary: The study simulates sensor coverage for hypothetical snow sensors to evaluate the efficiency of different sensors in observing terrestrial snow on a global scale. Results show the effectiveness achievable by different sensors over different snow types, with minimum required swath widths identified for different repeat intervals.
Review
Computer Science, Information Systems
Min Sheng, Di Zhou, Weigang Bai, Junyu Liu, Haoran Li, Yan Shi, Jiandong Li
Summary: This paper proposes coverage performance evaluation metrics in 6G STINs from the perspective of signal coverage, capacity coverage, and service coverage. By analyzing and comparing the coverage performance of several typical mega constellations, suitable network structure characteristics for 6G non-uniform service requirements are found, guiding constellation design in 6G STINs. Additionally, the application of artificial intelligence in resource collaboration is explored to enhance coverage capability for dynamic 6G service demands, and possible technical challenges for improving service coverage performance in 6G STINs are analyzed to provide researchers with new ideas.
SCIENCE CHINA-INFORMATION SCIENCES
(2023)
Article
Computer Science, Hardware & Architecture
Xiaobin Xu, Qi Wang, Yanzhao Hou, Shangguang Wang
Summary: This article proposes a cloud-edge aggregated artificial intelligent architecture for STINs, utilizing the edge computing platform of Tiansuan constellation to implement the intelligent network architecture. Three use cases are performed to achieve intelligent data transmission, intelligent remote sensing, and intelligent network slicing.
Article
Geochemistry & Geophysics
Xin Yang, Wenxiang Liu, Xiaozhou Ye, Xiangjun Li, Shipeng Wei, Feixue Wang
Summary: To provide secure and reliable PNT services, establishing resilient PNT is necessary due to limitations and vulnerabilities of GNSS platforms. UAV pseudolite navigation system can serve as an independent backup and augmentation system for GNSS. Optimizing the position of pseudolite systems is critical for better GDOP performance.
JOURNAL OF GEODESY
(2023)
Article
Biology
Zhaoxin Li, Caisheng Zhou, Yumei Chen, Wentao Ma, Yunlong Cheng, Jinxin Chen, Yu Bai, Wei Luo, Na Li, Erxia Du, Sheng Li
Summary: This study identifies the epidermal growth factor receptor (Egfr) as a crucial factor in promoting juvenile hormone (JH) biosynthesis in adult female German cockroaches. The study reveals the detailed molecular mechanism of Egfr signaling and its involvement in regulating JH biosynthesis. This provides new insights into the intricate regulation of JH biosynthesis during insect development.
Article
Engineering, Aerospace
Joshua Critchley-Marrows, Daniele Mortari
Summary: The risk to low Earth orbit space assets continues to increase in the 2020s, leading governments, militaries, and industries to prioritize mission assurance, resilience, and sustainability in space. This study explores the use of visual-based navigation to provide autonomous Positioning, Navigation, and Timing (PNT) for space domain users, addressing the need for alternative assurance methods that do not rely on external infrastructure. By adopting approaches from lunar navigation and utilizing known orbit mechanic models, accurate user position can be calculated and predicted with strong performance (100 m) in both lost-in-space scenarios and situations of denied service. This system capability can also be applied to future telecommunication mega-constellations, known as LEO PNT, to provide ranging signals for Earth users.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Environmental Sciences
Pyo-Woong Son, Sul Gee Park, Younghoon Han, Kiyeol Seo, Tae Hyun Fang
Summary: The eLoran system in Korea is the most technically advanced system developed to improve the safety of absolute positioning coordinates. By conducting sailing tests, it was found that the system can calculate the absolute position with an accuracy of approximately 15 meters with 95% probability during the port-approach stage.
Article
Engineering, Aerospace
David Arnas, Richard Linares
Summary: This paper focuses on the reconfiguration strategies for uniformly distributed satellite constellations and slotting architectures. It discusses reducing, maintaining, and increasing the number of available positions for satellites in a space structure, considering the minimum distances between spacecraft for system safety. Several approaches based on 2D Lattice Flower Constellations and the properties of uniformity and symmetries in these distributions are presented to solve the reconfiguration problem.
JOURNAL OF GUIDANCE CONTROL AND DYNAMICS
(2022)
Article
Computer Science, Information Systems
Xin Xu, Zhixiang Gao, Aijun Liu
Summary: This paper discusses the resilience of satellite constellation networks against attacks. Two types of robustness are focused on: topology-related network robustness and network function robustness related to routing mechanisms. The paper proposes satellite constellation network models, a new satellite importance index, and robustness metrics to assess the effects of attacks on satellites and links as well as the impact of resource allocation mechanisms on network robustness.
COMPUTER COMMUNICATIONS
(2023)
Article
Chemistry, Analytical
Qian Meng, Yuan Zhuang, Shengying Li
Summary: The ARAIM method utilizes multiple GNSS constellations to provide satellite navigation services, selecting the best two constellations for calculations to improve integrity availability and reduce computational complexity, showing superiority in both simulations and actual GNSS signal experiments.
Article
Engineering, Marine
Xiao Liang, Carl Milner, Christophe Macabiau, Philippe Estival
Summary: This paper discusses the opportunities and challenges related to using multiple DMEs as an alternative source of positioning, navigation, and timing, as well as improving the performance of A-PNT provided by multi-DMEs through the use of barometer altimeters and TACAN.
JOURNAL OF NAVIGATION
(2022)
Article
Remote Sensing
Amir Khodabandeh, Jinling Wang, Chris Rizos, Ahmed El-Mowafy
Article
Engineering, Civil
V Duong, K. Harima, S. Choy, D. Laurichesse, C. Rizos
Article
Engineering, Electrical & Electronic
Qiang Wang, Binghao Li, Chris Rizos
JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY
(2019)
Article
Geography, Physical
Viet Duong, Ken Harima, Suelynn Choy, Denis Laurichesse, Chris Rizos
JOURNAL OF SPATIAL SCIENCE
(2020)
Article
Environmental Sciences
Kan Wang, Ahmed El-Mowafy, Chris Rizos, Jinling Wang
Article
Engineering, Multidisciplinary
XingLi Gan, Wei Li, Ling Yang, Heng Zhang
MATHEMATICAL PROBLEMS IN ENGINEERING
(2020)
Article
Geochemistry & Geophysics
Ling Yang, Yunzhong Shen, Bofeng Li, Chris Rizos
Summary: The study presents quality control indices based on the DIA estimators and a simplified algebraic estimation (SAE) method for single outlier detection. By taking into account the uncertainty of the combined estimation-testing procedure, the accuracy and computational efficiency of quality control are improved.
JOURNAL OF GEODESY
(2021)
Correction
Environmental Sciences
Changjiang Hu, Craig Benson, Hyuk Park, Adriano Camps, Li Qiao, Chris Rizos
Article
Engineering, Electrical & Electronic
Ling Yang, Yangkang Yu, Bofeng Li
Summary: This paper proposes a multi-floor indoor localization method using a radial basis function (RBF) network for floor detection and location estimation. The network is constructed based on a probabilistic algorithm, and supervised learning is conducted using Gaussian radial basis functions to ensure accuracy and stability in localization.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2021)
Article
Environmental Sciences
Olga Pimenova, Craig Roberts, Chris Rizos
Summary: This study calculated a 1'' Bare-Earth Digital Terrain Model for Costa Rica by reducing the Vegetation Bias from NASADEM based on SRTM data. Various global models were used to represent vegetation, and four analytical VB models based on canopy heights and density were evaluated and validated. Results showed that the differences between CRDTM2020 and bare-earth elevations were smaller compared to other global DEMs.
Article
Remote Sensing
Chunyuan Zhou, Ling Yang, Bofeng Li, Timo Balz
Summary: Ionospheric delay is a significant error source for GNSS, and it needs to be modeled and analyzed. To address the lack of open-source ionospheric modeling software, a multi-system global and regional ionospheric modeling software called M_GIM is introduced, based on the M_DCB. It has been evaluated and proved reliable, with similar accuracy to individual ionosphere associate analysis centers (IAACs) final and rapid global ionosphere map (GIM) products.
Article
Chemistry, Analytical
Ling Yang, Nan Sun, Chris Rizos, Yiping Jiang
Summary: This study improves the stochastic models for vehicle-based GNSS positioning under the ARAIM framework. The refinements include using Gaussian bounds for precise orbit and clock error, adopting variable standard deviation for residual tropospheric delay, and adaptively refining an elevation-dependent model using least-squares variance component estimation. The enhancements are assessed through global simulations and real data experiments, with different schemes designed and tested for aviation and ground vehicle-based positioning applications.
Article
Engineering, Civil
Tianxia Liu, Bofeng Li, Guang'e Chen, Ling Yang, Jing Qiao, Wu Chen
Summary: This paper investigates the localization problem of autonomous vehicles in complex indoor-outdoor environments and proposes a tightly coupled integration algorithm of GNSS RTK, UWB, and VIO. Experimental results show that the proposed algorithm achieves high positioning accuracy and reliability in indoor-outdoor obscured environments.
IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS
(2023)
