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Thermosphere joint observations by TM-1 constellations and Swarm-B during the April 2023 geomagnetic storm
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作者 YongPing Li YueQiang Sun +9 位作者 XianGuo Zhang JiangZhao Ai XiaoLiang Zheng Jia Li YuJie Wang BiBo Guo Feng Yan ShiLong Wei XinChun Tang YuanYuan Cao 《Earth and Planetary Physics》 EI CAS CSCD 2024年第2期307-316,共10页
The response of thermosphere density to geomagnetic storms is a complicated physical process.Multi-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this p... The response of thermosphere density to geomagnetic storms is a complicated physical process.Multi-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this process;however,until now such studies have hardly been done.In this report,we analyze in detail the thermosphere mass density response at 510 km during the April 23−24,2023 geomagnetic storm using data derived from the TM-1(TianMu-1)satellite constellation and Swarm-B satellites.The observations show that there were significant LT differences in the hemispheric asymmetry of the thermosphere mass density during the geomagnetic storm.Densities observed by satellite TM02 at nearly 11.3 and 23.3 LTs were larger in the northern hemisphere than in the southern.The TM04 dayside density observations appear to be almost symmetrical with respect to the equator,though southern hemisphere densities on the nightside were higher.Swarm-B data exhibit near-symmetry between the hemispheres.In addition,the mass density ratio results show that TM04 nightside observations,TM02 data,and Swarm-B data all clearly show stronger effects in the southern hemisphere,except for TM04 on the dayside,which suggest hemispheric near-symmetry.The South-North density enhancement differences in TM02 and TM04 on dayside can reach 130%,and Swarm-B data even achieve 180%difference.From the observations of all three satellites,large-scale traveling atmospheric disturbances(TADs)first appear at high latitudes and propagate to low latitudes,thereby disturbing the atmosphere above the equator and even into the opposite hemisphere.NRLMSISE00 model simulations were also performed on this geomagnetic storm.TADs are absent in the NRLMSISE00 simulations.The satellite data suggest that NRLMSISE00 significantly underestimates the magnitude of the density response of the thermosphere during geomagnetic storms,especially at high latitudes in both hemispheres.Therefore,use of the density simulation of NRLMSISE00 may lead to large errors in satellite drag calculations and orbit predictions.We suggest that the high temporal and spatial resolution of direct density observations by the TM-1 constellation satellites can provide an autonomous and reliable basis for correction and improvement of atmospheric models. 展开更多
关键词 TM-1 constellation Swarm-B joint observations geomagnetic storm Local Times
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Uniquely Decomposable Constellation Group-Based Sparse Vector Coding for Short Packet Communications
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作者 Xuewan Zhang Hongyang Chen +3 位作者 Di Zhang Ganyu Qin Battulga Davaasambuu Takuro Sato 《China Communications》 SCIE CSCD 2023年第5期119-134,共16页
Sparse vector coding(SVC)is emerging as a potential technology for short packet communications.To further improve the block error rate(BLER)performance,a uniquely decomposable constellation group-based SVC(UDCG-SVC)is... Sparse vector coding(SVC)is emerging as a potential technology for short packet communications.To further improve the block error rate(BLER)performance,a uniquely decomposable constellation group-based SVC(UDCG-SVC)is proposed in this article.Additionally,in order to achieve an optimal BLER performance of UDCG-SVC,a problem to optimize the coding gain of UDCG-based superimposed constellation is formulated.Given the energy of rotation constellations in UDCG,this problem is solved by converting it into finding the maximized minimum Euclidean distance of the superimposed constellation.Simulation results demonstrate the validness of our derivation.We also find that the proposed UDCGSVC has better BLER performance compared to other SVC schemes,especially under the high order modulation scenarios. 展开更多
关键词 ultra-reliable and low latency communications sparse vector coding uniquely decomposable constellation group constellation rotation short packet communications
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Local-State Routing in Satellite Constellation Networks from the Perspective of Complex Network
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作者 Xin Xu Jun Cai +2 位作者 Aijun Liu Chaoying Dong Chen Han 《China Communications》 SCIE CSCD 2023年第7期72-88,共17页
Routing algorithms in satellite constellation networks usually make use of the local state information to adapt to the topology and traffic dynamics,since it’s difficult to obtain the global states in time due to the... Routing algorithms in satellite constellation networks usually make use of the local state information to adapt to the topology and traffic dynamics,since it’s difficult to obtain the global states in time due to the spatial large-scale feature of constellation networks.Furthermore,they use different range of local states and give these states distinct weights.However,the behind design criterion is ambiguous and often based on experience.This paper discusses the problem from the perspective of complex network.A universal local-state routing model with tunable parameters is presented to generalize the common characteristics of local-state routing algorithms for satellite constellation networks.Based on this,the impacts of localstate routing algorithms on performance and the correlation between routing and traffic dynamics are analyzed in detail.Among them,the tunable parameters,the congestion propagation process,the critical packet sending rate,and the network robustness are discussed respectively.Experimental results show that routing algorithms can achieve a satisfactory performance by maintaining a limited state awareness capability and obtaining the states in a range below the average path length.This provides a valuable design basis for routing algorithms in satellite constellation networks. 展开更多
关键词 satellite constellation local state routing traffic dynamics complex networks ROBUSTNESS
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Low Altitude Satellite Constellation for Futuristic Aerial-Ground Communications
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作者 Saifur Rahman Sabuj Mohammad Saadman Alam +2 位作者 Majumder Haider Md Akbar Hossain Al-Sakib Khan Pathan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第8期1053-1089,共37页
This paper discusses the significance and prospects of low altitude small satellite aerial vehicles to ensure smooth aerial-ground communications for next-generation broadband networks.To achieve the generic goals of ... This paper discusses the significance and prospects of low altitude small satellite aerial vehicles to ensure smooth aerial-ground communications for next-generation broadband networks.To achieve the generic goals of fifthgeneration and beyondwireless networks,the existing aerial network architecture needs to be revisited.The detailed architecture of low altitude aerial networks and the challenges in resource management have been illustrated in this paper.Moreover,we have studied the coordination between promising communication technologies and low altitude aerial networks to provide robust network coverage.We talk about the techniques that can ensure userfriendly control and monitoring of the low altitude aerial networks to bring forth wireless broadband connectivity to a new dimension.In the end,we highlight the future research directions of aerial-ground communications in terms of access technologies,machine learning,compressed sensing,and quantum communications. 展开更多
关键词 Aerial-terrestrial network cognitive radio network cooperative communication high altitude platform low altitude platform low earth orbit satellite constellation unmanned aerial vehicle
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A Unified Bit-to-Symbol Mapping for Generalized Constellation Modulation
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作者 Lixia Xiao Xiaodan Zhai +3 位作者 Yangyang Liu Guanghua Liu Pei Xiao Tao Jiang 《China Communications》 SCIE CSCD 2023年第6期229-239,共11页
Gray mapping is a well-known way to improve the performance of regular constellation modulation,but it is challenging to be applied directly for irregular alternative.To address this issue,in this paper,a unified bit-... Gray mapping is a well-known way to improve the performance of regular constellation modulation,but it is challenging to be applied directly for irregular alternative.To address this issue,in this paper,a unified bit-to-symbol mapping method is designed for generalized constellation modulation(i.e.,regular and irregular shaping).The objective of the proposed approach is to minimize the average bit error probability by reducing the hamming distance(HD)of symbols with larger values of pairwise error probability.Simulation results show that the conventional constellation modulation(i.e.,phase shift keying and quadrature amplitude modulation(QAM)with the proposed mapping rule yield the same performance as that of classical gray mapping.Moreover,the recently developed golden angle modulation(GAM)with the proposed mapping method is capable of providing around1 d B gain over the conventional mapping counterpart and offers comparable performance to QAM with Gray mapping. 展开更多
关键词 gray mapping generalized constellation modulation golden angle modulation(GAM) pairwise error probability(PEP) hamming distance(HD)
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A Performance Evaluation Platform for Mega Satellite Constellation Network
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作者 Yifei Jiang Wanxia He +3 位作者 Shufan Wu Lili Zuo Weixin Zhang Qiankun Mo 《Journal of Computer and Communications》 2023年第6期122-130,共9页
With the rapid development of satellite technology, mega satellite constellations have become a research hotspot. A large number of related techniques have been developed on orbit topology, network routing, energy bal... With the rapid development of satellite technology, mega satellite constellations have become a research hotspot. A large number of related techniques have been developed on orbit topology, network routing, energy balance and resource control. However, it is difficult to accurately compare the performance of similar studies due to differences in the means of validation. Especially for invulnerability studies in many military applications, a unified evaluation system is essential. This paper proposes a network evaluation system for mega satellite constellations. Evaluation parameters include orbit topology, communication network, energy balance and invulnerability. Different application algorithms and traffic models were used to validate the specific system. . 展开更多
关键词 Mega constellation Satellite Communication Network Evaluation
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Constellation玻切机使用中的维护与保养 被引量:1
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作者 苑建捧 刘维维 《中国妇幼健康研究》 2017年第S2期328-329,共2页
玻切机是用于眼前段(超声乳化白内障吸出术和白内障摘除术)和眼后段(玻璃体视网膜术)手术不可或缺的基本设备,也是最昂贵的手术设备之一。最新一代Constellation玻切机自2010年上市以来,一直以高安全、高效率、高智能化占居全球玻切设... 玻切机是用于眼前段(超声乳化白内障吸出术和白内障摘除术)和眼后段(玻璃体视网膜术)手术不可或缺的基本设备,也是最昂贵的手术设备之一。最新一代Constellation玻切机自2010年上市以来,一直以高安全、高效率、高智能化占居全球玻切设备市场第一,受到了广大医护人员的欢迎。Constellation玻切机的正常运行直接影响着手术的效率和效果,所以对Constellation玻切机使用中的维护与保养显得尤为重要。 展开更多
关键词 constellation玻切机 使用安装 注意事项 维护 故障排除
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COVERAGE PERFORMANCES ANALYSIS ON COMBINED-GEO-IGSO SATELLITE CONSTELLATION 被引量:12
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作者 Jiang Yong Yang Sen +1 位作者 Zhang Gengxin Li Guangxia 《Journal of Electronics(China)》 2011年第2期228-234,共7页
The Combined-GEO-IGSO constellation is the combination of Geostationary Earth Orbit(GEO) satellite and Inclining GeoSynchronous Orbit(IGSO) satellite.The Combined-GEO-IGSO constellation can integrate the advantages of... The Combined-GEO-IGSO constellation is the combination of Geostationary Earth Orbit(GEO) satellite and Inclining GeoSynchronous Orbit(IGSO) satellite.The Combined-GEO-IGSO constellation can integrate the advantages of GEO and IGSO to achieve regional coverage.In order to discuss the performances of the Combined-GEO-IGSO constellation,the performances of coverage,elevation,diversity,and transmission are simulated in China and surrounding regions by Satellite Tool Kit(STK).The simulation results show that:the combined constellation can reach higher multi-satellite coverage and higher communication elevation in China and surrounding areas;the Doppler shift,delay,and propagation loss of this constellation have little impact on the system.As regional coverage constellation,the Combined-GEO-IGSO is feasible. 展开更多
关键词 constellation Geostationary Earth Orbit(GEO) Inclining GeoSynchronous Orbit(IGSO) Combined-GEO-IGSO Doppler shift
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Satellite Constellation Design with Adaptively Continuous Ant System Algorithm 被引量:5
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作者 He Quan Han Chao 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2007年第4期297-303,共7页
The ant system algorithm (ASA) has proved to be a novel meta-heuristic algorithm to solve many multivariable problems. In this paper, the earth coverage of satellite constellation is analyzed and a n + 1^ -fold cov... The ant system algorithm (ASA) has proved to be a novel meta-heuristic algorithm to solve many multivariable problems. In this paper, the earth coverage of satellite constellation is analyzed and a n + 1^ -fold coverage rate is put forward to evaluate the coverage performance of a satellite constellation. An optimization model of constellation parameters is established on the basis of the coverage performance. As a newly developed method, ASA can be applied to optimize the constellation parameters. In order to improve the ASA, a rule for adaptive number of ants is proposed, by which the search range is obviously enlarged and the convergence speed increased. Simulation results have shown that the ASA is more quick and efficient than other methodV211.71s. 展开更多
关键词 ant system algorithm satellite constellation optimization design coverage performance adaptive adjusting
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Sensor management of LEO constellation based on covariance control 被引量:4
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作者 QIN Zheng LIANG Yan'gang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第2期393-401,共9页
This paper studies the multi-sensor management problem for low earth orbit(LEO) infrared warning constellation used to track a midcourse missile. A covariance control approach, which selects sensor combinations or sub... This paper studies the multi-sensor management problem for low earth orbit(LEO) infrared warning constellation used to track a midcourse missile. A covariance control approach, which selects sensor combinations or subset based on the difference between the desired covariance matrix and the actual covariance of each target, is used for sensor management, including some matrix metrics to measure the differentia between two covariance matrices. Besides, to meet the requirements of the space based warning system, the original covariance control approach is improved. Simulation results demonstrate that the covariance control approach is able to provide a better tracking performance by providing a well-designed desired covariance and balance tracking performance goals with system demands. 展开更多
关键词 sensor management COVARIANCE control TARGET TRACKING ACCURACY LEO constellation
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Analysis of detection capabilities of LEO reconnaissance satellite constellation based on coverage performance 被引量:10
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作者 MENG Shaofei SHU Jiansheng +1 位作者 YANG Qi XIA Wei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第1期98-104,共7页
In the design problem of low earth orbit(LEO) reconnaissance satellite constellation, optimization of coverage performance is the design goal in most current methods. However,in the using process, the user only concer... In the design problem of low earth orbit(LEO) reconnaissance satellite constellation, optimization of coverage performance is the design goal in most current methods. However,in the using process, the user only concerns with the detection capabilities rather than coverage performance. To establish the relationship between these two aspects, the reconnaissance processes of normal stochastic targets are considered and the mathematic models of detection processes are built. The indicators of coverage performance are used to evaluate the detection probability and expectation of detection time delay, which are important factors in reconnaissance constellation estimation viewed from military intelligence discipline. The conclusions confirmed by the final simulation will be useful in LEO reconnaissance constellation design, optimization and evaluation. 展开更多
关键词 low earth orbit(LEO) reconnaissance satellite constellation detection capability Monte Carlo experiment
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Information gain based sensor search scheduling for low-earth orbit constellation estimation 被引量:3
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作者 Bo Wang Jun Li +1 位作者 Wei An Yiyu Zhou 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第6期926-932,共7页
This paper addresses the problem of sensor search scheduling in the complicated space environment faced by the low-earth orbit constellation.Several search scheduling methods based on the commonly used information gai... This paper addresses the problem of sensor search scheduling in the complicated space environment faced by the low-earth orbit constellation.Several search scheduling methods based on the commonly used information gain are compared via simulations first.Then a novel search scheduling method in the scenarios of uncertainty observation is proposed based on the global Shannon information gain and beta density based uncertainty model.Simulation results indicate that the beta density model serves a good option for solving the problem of target acquisition in the complicated space environments. 展开更多
关键词 low-earth orbit constellation sensor network scheduling algorithm information gain acquisition.
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6G Service Coverage with Mega Satellite Constellations 被引量:5
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作者 Min Sheng Di Zhou +2 位作者 Weigang Bai Junyu Liu Jiandong Li 《China Communications》 SCIE CSCD 2022年第1期64-76,共13页
The rapid development and continuous updating of the mega satellite constellation(MSC)have brought new visions for the future 6G coverage extension, where the global seamless signal coverage can realize ubiquitous ser... The rapid development and continuous updating of the mega satellite constellation(MSC)have brought new visions for the future 6G coverage extension, where the global seamless signal coverage can realize ubiquitous services for user terminals. However, global traffic demands present nonuniform characteristics. Therefore, how to ensure the on-demand service coverage for the specific traffic demand, i.e., the ratio of traffic density to service requirement per unit area, is the core issue of 6G wireless coverage extension exploiting the MSC. To this regard, this paper first discusses the open challenges to reveal the future direction of 6G wireless coverage extension from the perspective of key factors affecting service coverage performance, i.e., the network access capacity, space segment capacity and their matchingrelationship. Furthermore, we elaborate on the key factors affecting effective matchings of the aforementioned aspects, thereby improving service coverage capability. 展开更多
关键词 6G mega satellite constellations on-demand service coverage un-uniform traffic demands resource management
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AI-Enhanced Constellation Design for NOMA System: A Model Driven Method 被引量:3
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作者 Sen Wang Hanxiao Yu +2 位作者 Yifei Yuan Guangyi Liu Zesong Fei 《China Communications》 SCIE CSCD 2020年第11期100-110,共11页
Grant-free Non-orthogonal Multiple Access(GF-NOMA)is a promising technology for massive access users and sporadic small-packet transmission for Beyond the 5th Generation mobile communication system(B5G)/the 6th Genera... Grant-free Non-orthogonal Multiple Access(GF-NOMA)is a promising technology for massive access users and sporadic small-packet transmission for Beyond the 5th Generation mobile communication system(B5G)/the 6th Generation mobile communication system(6G).One of the key aspects in GF-NOMA system is the signature/constellation design.However,due to the channel variation and random activation of users,conventional optimization approaches seem unsuitable for such complex models.In this paper,as an initial attempt,we propose a human intelligence(HI)-guided artificial intelligence(AI)-enhanced signature/constellation design method.By separate design of modulation and power allocation inspired by prior knowledge,the proposed deep neuron network(DNN)for NOMA signature/constellation design not only has smaller size of DNN and less training data,but also has stronger interpretability.In the last section,via simulations we demonstrate that in terms of bit error rate,the proposed scheme can achieve significant performance gain over the conventional NOMA schemes. 展开更多
关键词 NOMA system DNN constellation design power allocation
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Polar-Coded Modulation Based on the Amplitude Phase Shift Keying Constellations 被引量:1
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作者 Dekun Zhou Jincheng Dai +4 位作者 Kai Niu Chao Dong Jingyuan Sun Yi Zhang Hao Guan 《China Communications》 SCIE CSCD 2017年第9期166-177,共12页
In this paper, we investigate the polarization effect of the amplitude phase shift keying(APSK) constellations. We find that the polarization effect of the APSK constellations is affected by the bit mapping and the bi... In this paper, we investigate the polarization effect of the amplitude phase shift keying(APSK) constellations. We find that the polarization effect of the APSK constellations is affected by the bit mapping and the bit loading. Traditionally, the Gray mapping is usually adopted in APSK constellations. Based on the given Gray mapping, we firstly propose the bit interleaved coded modulation polar-APSK(BICM-PA) scheme, which neglects the correlations between the bit levels by using the bit interleaver. In the BICM-PA scheme, a new metric called cumulative Bhattacharyya parameter is introduced to optimize the bit loading of the APSK constellations under the Gray mapping. Second, the multilevel coded modulation polar-APSK(MLCM-PA) is proposed to further improve the performance. A twostage optimization approach is adopted to select the bit mapping and the bit loading in the MLCM-PA scheme. The semi-set partitioning mapping is introduced to achieve a better system performance in the MLCM-PA scheme. Simulation results verify the effectiveness of all the proposed metrics. In addition to this, BICM-PA and MLCM-PA both outperform the coded modulation Turbo-APSK scheme up to 1 dB. 展开更多
关键词 APSK constellationS BICM-PA MLCM-PA TWO-STAGE optimization semi-setpartitioning
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Comparison between several satellite constellation schemes for MEO-TDRSS of China 被引量:2
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作者 Wu Tingyong Wu Shiqi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第5期907-913,共7页
The satellite constellation classes, which are suitable for the medium earth orbit tracking and data relay satellite system (MEO-TDRSS) of China, are investigated. On the basis of the functionality and the traffic d... The satellite constellation classes, which are suitable for the medium earth orbit tracking and data relay satellite system (MEO-TDRSS) of China, are investigated. On the basis of the functionality and the traffic distribution characteristic of MEO-TDRSS, the coverage performance and inter-satellite link properties of four different constellation schemes are compared by simulations. Simulation results indicate that the rosette and common-track constellations, whose satellites are distributed on the celestial sphere more uniformly, are appropriate for the implementation of MEO-TDRSS of China. 展开更多
关键词 medium earth orbit tracking and data relay satellite system (MEO-TDRSS) satellite constellation inter-satellite links.
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Simulation of earth gravity field using satellite constellation with variable inclination configuration 被引量:1
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作者 Qian Zhao Weiping Jiang +1 位作者 Xinyu Xu Xiancai Zou 《Geodesy and Geodynamics》 CSCD 2021年第5期323-328,共6页
Based on a satellite constellation composed of two GRACE-type satellite formations with different inclinations(near polar orbit + low inclination) and the theory of repeat orbit cycle, we discuss the methods for selec... Based on a satellite constellation composed of two GRACE-type satellite formations with different inclinations(near polar orbit + low inclination) and the theory of repeat orbit cycle, we discuss the methods for selecting medium-low inclinations for global and local gravity fields. The effects of this constellation configuration on gravity field inversion are comparatively analyzed using a whole-course dynamics simulation. The results show that compared with the single GRACE-type satellite formation,the use of satellite constellations with different inclination configurations improves the gravity solution precision by 34%. The inclusion of multi-directional observations can improve the spatio-temporal resolution of the satellite missions, and yield gravity field solutions with higher isotropic sensitivity.Furthermore, it is necessary to select the optimal low inclination according to the study area, which will have a significant influence on the gravity field solution. 展开更多
关键词 Satellite constellation Low inclination Multi-directional observations Inversion of gravity field
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Optimal reconfiguration of constellation using adaptive innovation driven multiobjective evolutionary algorithm 被引量:1
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作者 HU Jiaxin YANG Leping +1 位作者 HUANG Huan ZHU Yanwei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第6期1527-1538,共12页
Constellation reconfiguration is a critical issue to recover from the satellite failure,maintain the regular operation,and enhance the overall performance.The constellation reconfiguration problem faces the difficulti... Constellation reconfiguration is a critical issue to recover from the satellite failure,maintain the regular operation,and enhance the overall performance.The constellation reconfiguration problem faces the difficulties of high dimensionality of design variables and extremely large decision space due to the great and continuously growing constellation size.To solve such real-world problems that can be hardly solved by traditional algorithms,the evolutionary operators should be promoted with available domain knowledge to guide the algorithm to explore the promising regions of the trade space.An adaptive innovationdriven multi-objective evolutionary algorithm(MOEA-AI)employing automated innovation(AI)and adaptive operator selection(AOS)is proposed to extract and apply domain knowledge.The available knowledge is extracted from the final or intermediate solution sets and integrated into an operator by the automated innovation mechanism.To prevent the overuse of knowledgedependent operators,AOS provides top-level management between the knowledge-dependent operators and conventional evolutionary operators.It evaluates and selects operators according to their actual performance,which helps to identify useful operators from the candidate set.The efficacy of the MOEAAI framework is demonstrated by the simulation of emergency missions.It was verified that the proposed algorithm can discover a non-dominant solution set with better quality,more homogeneous distribution,and better adaptation to practical situations. 展开更多
关键词 constellation reconfiguration emergency observations rapid response multi-objective optimization
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The principle of a navigation constellation composed of SIGSO communication satellites 被引量:1
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作者 Hai-Fu Ji Li-Hua Ma +1 位作者 Guo-Xiang Ai Hu-Li Shi 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2013年第4期479-489,共11页
The Chinese Area Positioning System (CAPS), a navigation system based on geostafionary orbit (GEO) communication satellites, was developed in 2002 by astronomers at Chinese Academy of Sciences. Extensive positioni... The Chinese Area Positioning System (CAPS), a navigation system based on geostafionary orbit (GEO) communication satellites, was developed in 2002 by astronomers at Chinese Academy of Sciences. Extensive positioning experiments of CAPS have been performed since 2005. On the basis of CAPS, this paper studies the principle of a navigation constellation composed of slightly inclined geostationary orbit (SIGSO) communication satellites. SIGSO satellites are derived from GEO satellites which are near the end of their operational life by inclined orbit operation. Considering the abundant frequency resources of SIGSO satellites, multi-frequency observations could be conducted to enhance the precision of pseudorange measurements and ameliorate the positioning performance. A constellation composed of two GEO satellites and four SIGSO satellites with an inclination of 5° can provide service to most of the territory of China with a maximum position dilution of precision (PDOP) over 24 h of less than 42. With synthetic utilization of the truncated precise code and a physical augmentation factor in four frequencies, the navigation system with this constellation is expected to obtain comparable positioning performance to that of the coarse acquisition code of the Global Positioning System (GPS). When the new method of code-carrier phase combinations is adopted, the system has the potential to possess commensurate accuracy with the precise code in GPS. Additionally, the copious frequency resources can also be used to develop new anti-interference techniques and integrate navigation and communication. 展开更多
关键词 astrometry and celestial mechanics - astronomy application-artificial satellite - satellite navigation constellation
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Conceptual Design Process for LEO Satellite Constellations Based on System Engineering Disciplines
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作者 Ali Salehi Mahdi Fakoor +1 位作者 Amirreza Kosari Seyed Mohammad Navid Ghoreishi 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第5期599-618,共20页
Satellite design process is an interdisciplinary subject in which the need for collaboration among various science and engineering disciplines is evident.Meanwhile,finding an optimal process for conceptual design of a... Satellite design process is an interdisciplinary subject in which the need for collaboration among various science and engineering disciplines is evident.Meanwhile,finding an optimal process for conceptual design of a satellite,which can optimize time and cost,is still an important issue.In this paper,based on system engineering approach,an optimal design process is proposed for LEO satellite constellations.In the proposed method,design process,design sequences,and data flow are established.In this regard,the conceptual design process is divided into two levels of mission(or constellation)and system(or satellite)as well as 15 main activities based on the mission profile,previous experiences of the authors,and existing literature.Then,the relationships between these activities have been determined by considering the importance of relationships according to their priority.Finally,these relations are optimized based on design structure matrix(DSM).By utilizing this approach,system design process of a telecommunication satellite constellation in LEO is formulated in conceptual design phase.Performance and capability of the proposed approach in optimal design process of the satellite constellation are investigated by comparing the outcome with existing results in the literature. 展开更多
关键词 Satellite constellation system engineering design structure matrix conceptual design
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