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Precise orbit determination for a large leo constellation with inter-satellite links and the measurements from different ground networks:a simulation study

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satellite Navigation 2022年第3期3卷 38-50,I0002页

作者： Xingchi He Urs Hugentobler Anja Schlicht Yufeng Nie Bingbing Duan Institute for Astronomical and Physical Geodesy Technical University of MunichArcisstr.2180333MunichGermany College of Surveying and Geo-Informatics Tongji UniversitySiping Road 1239Shanghai200092China

Geodetic applications of Low Earth Orbit(leo)satellites requires accurate satellite orbits.Instead of using onboard Global Navigation satellite System observations,this contribution treats the leo satellite constellation independently,using Inter-satellite Links and the measurements of different ground networks.Due to geopolitical and geographical reasons,a ground station network cannot be well distributed.We compute the impact of different ground networks(i.e.,global networks with different numbers of stations and regional networks in different areas and latitudes)on leo satellite orbit determination with and without the inter-satellite links.The results are based on a simulated constellation of 90 leo satellites.We find that the orbits determined using a high latitude network is worse than using a middle or low latitude network.This is because the high latitude network has a poorer geometry even if the availability of satellite measurements is higher than for the other two cases.Also,adding more stations in a regional network shows almost no improvements on the satellite orbits if the number of stations is more than 16.With the help of ISL observations,however,the satellite orbits determined with a small regional network can reach the same accuracy as that with the global network of 60 stations.Furthermore,satellite biases can be well estimated(less than 0.6 mm)and have nearly no impact on satellite orbits.It does thus not matter if they are not physically calibrated for estimating precise orbits.

关键词： leo satellite Orbit determination Ground station distribution Inter-satellite link

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NOMA-Based Collaborative Beam Hopping Frequency Allocation Mechanism for Future leo satellite Systems

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China Communications 2023年第6期20卷 321-338页

作者： Fei Zheng Zhao Pi Zou Zhou Miao Ye Hongbing Qiu Ministry of Education Key Laboratory of Cognitive Radio and Information Processing Guilin University of Electronic TechnologyGuilin 541004China State key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

Low Earth orbit(leo) satellite systems provide terrestrial users with services that are not limited by geographical location. However, the conflict between existing allocation schemes and the business variability between beams is becoming increasingly prominent. Beam hopping technology allows for a more flexible and versatile approach to satellite resource allocation. This paper proposes a beam hopping pattern optimization scheme that jointly considers the interference threshold distance and beam service priority, reducing the inter-beam co-channel interference(CCI). In the cluster area, a non-orthogonal multiple access(NOMA)-based collaborative beam hopping(NCBH) scheme is proposed to minimize the cell-edge user(CEU) interference. Since there is a difference in channel gain between the CEU and cellcenter user(CCU), this scheme forms a NOMA cluster to perform power domain multiplexing and formulates a NOMA cluster pairing strategy according to the user location to reduce the CCI of the CEU. After NOMA cluster pairing, the optimal carrier frequency of the NOMA cluster is selected by a reinforcement learning algorithm. The simulation results verify the excellent performance of the proposed NCBH scheme regarding the user’s received power, transmission rate, and outage probability.

关键词： leo satellite beam hopping NOMA resource allocation

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LoS MIMO Transmission for leo satellite Communication Systems

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China Communications 2022年第10期19卷 180-193页

作者： Lingxuan Li Tingting Chen Wenjin Wang Xiaohang Song Li You Xiqi Gao National Mobile Communications Research Laboratory Southeast UniversityNanjing 210096China Vodafone Chair Mobile Communications Systems Technische Universität Dresden01062 DresdenGermany

To provide global service with low latency, the broadband low earth orbits (leo) satellite constellation based communication systems have become one of the focuses in academic and industry. To allow for wideband access for user links, the feeder link of leo satellite is correspondingly required to support high throughput data communications. To this end, we propose to apply line-of-sight (LoS) multiple-input multiple-output (MIMO) transmission for the feeder link to achieve spatial multiplexing by optimizing the antenna arrangement. Unlike the LoS MIMO applications for static scenarios, the movement of leo satellites make it impractical to adjust the optimal antenna separation for all possible satellite positions. To address this issue, we propose to design the antenna placement to maximize the ergodic channel capacity during the visible region of the ground station. We first derive the closed-form probability distribution of the satellite trajectory in visible region. Based on which the ergodic channel capacity can be then calculated numerically. The antenna placement can be further optimized to maximize the ergodic channel capacity. Numerical results verify the derived probability distribution of the satellite trajectory, and show that the proposed LoS MIMO scheme can significantly increase the ergodic channel capacity compared with the existing SISO one.

关键词： LoS MIMO leo satellite ergodic channel capacity Beyond 5G

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A Safe and Reliable Routing Mechanism of leo satellite Based on SDN

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Computers, Materials & Continua 2020年第7期64卷 439-454页

作者： Chao Guo Juan Guo Chanjuan Yu Zhaobin Li Cheng Gong Abdul Waheed Department of Electronics and Communication Engineering Beijing Electronic Science and Technology InstituteBeijing100070China Vocational and Technical College Guilin University of Electronic TechnologyBeihai536000China School of Computer and Communication Engineering University of Science and Technology BeijingBeijing100083China University of Management Technology Lahore55300Pakistan

satellite networks have high requirements for security and data processing speed.In order to improve the reliability of the network,software-defined network(SDN)technology is introduced and a central controller is set in the network.Due to the characteristics of global perspective,control data separation,and centralized control of SDN,the idea of SDN is introduced to the design of the satellite network model.As a result,satellite nodes are only responsible for data transmission,while the maintenance of the links and the calculation of routes are implemented by the controller.For the massive leo satellite network based on SDN,a state evaluation decision routing mechanism is proposed.The designed mechanism monitors the status of the entire network effectively and reduces the on-board load on the satellite network.The best routing decision is made under the comprehensive consideration of the current and historical status of each inter-satellite link between Low Earth Orbit(leo)satellite network nodes.The calculation and storage requirements are controlled within a reasonable range.Based on the curve parameter transmission fuzzy encryption algorithm,a safe and reliable condition assessment decision routing mechanism(CADRM)is designed.It ensures that the personal information of the leo satellite network can be transmitted safely and effectively.The experimental simulation results show the improvement of network throughput,the reduction of packet loss rate and the enhancing of network reliability.

关键词： Route leo satellite SDN state assessment inter-satellite link

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Adaptive Tracking for Beam Alignment Between Ship-Borne Digital Phased-Array Antenna and leo satellite

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Journal of Communications and Information Networks 2019年第3期4卷 60-70页

作者： Qin Chen Yuying Xu Chunyi Song Zhiwei Xu Institute of Marine Electronic and Intelligent System Ocean CollegeZhejiang UniversityZhoushan 316021China Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province Zhoushan 316021China

In mobile satellite communication networks employing digital beam forming technology,beam alignment imposes great influence on link quality and network efficiency.Owing to complex coupling motion by low earth orbit(leo)satellite and ship,direction of arrival(DOA)of target satellite varies rapidly and nonlinearly.It then causes difficulty to accurately track the DOA.In this work,an adaptive tracking algorithm is proposed by exploiting advantages of flexible parameter configuration of digital phased-array antenna.The alignment process basically consists of observation and tracking.In the observation stage,two-dimensional(2-D)multiple signal classification(MUSIC)is applied by the ship-borne digital phased-array antenna to estimate beam direction of satellite;in the tracking stage,an extended Kalman filter(EKF)based adaptive tracking is designed to achieve fast and accurate alignment.The proposed adaptive tracking improves performance by adaptively estimating tracking parameters in EKF firstly.The estimation results are then used as feedback to adaptively adjust digital phased-array antenna parameters to improve estimation accuracy of DOA.Simulation results under sea state 5 show that the proposed tracking algorithm improves tracking accuracy and stability over conventional ones.

关键词： satellite communication on-the-move adaptive tracking alignment of antenna leo satellite shipborne communication digital phased-array antenna

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OTFS Enabled NOMA for MMTC Systems over leo satellite

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ZTE Communications 2021年第4期19卷 63-70页

作者： MA Yiyan MA Guoyu WANG Ning ZHONG Zhangdui AI Bo Beijing Jiaotong University Beijing 100044China Zhengzhou University Zhengzhou 450001China Peng Cheng Laboratory Shenzhen 518000China

As a complement of terrestrial networks,non-terrestrial networks(NTN)have ad⁃vantages of wide-area coverage and service continuity.The NTN is potential to play an impor⁃tant role in the 5G new radio(NR)and beyond.To enable the massive machine type communi⁃cations(mMTC),the low earth orbit(leo)satellite is preferred due to its lower transmission delay and path loss.However,the leo satellite may generate notable Doppler shifts to de⁃grade the system performance.Recently,orthogonal time frequency space(OTFS)modulation has been proposed.It provides the opportunity to allocate delay Doppler(DD)domain resourc⁃es,which is promising for mitigating the effect of high mobility.Besides,as the leo satellite constellation systems such as Starlink are thriving,the space spectrum resources have become increasingly scarce.Therefore,non-orthogonal multiple access(NOMA)is considered as a candidate technology to realize mMTC with limited spectrum resources.In this paper,the ap⁃plication of OTFS enabled NOMA for mMTC over the leo satellite is investigated.The leo satellite based mMTC system and the OTFS-NOMA schemes are described.Subsequently,the challenges of applying OTFS and NOMA into leo satellite mMTC systems are discussed.Fi⁃nally,the potential technologies for the systems are investigated.

关键词： mMTC leo satellite OTFS NOMA

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satellite-Ground Link Planning Method for leo satellite Navigation Augmentation Network in the case of Multiple Ground Stations

Satellite-Ground Link Planning Method for LEO Satellite Navi...

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第十三届中国卫星导航年会

作者： Yanghongyi Kuang Xianqing Yi Zhenwei Hou Science and Technology on Information Systems Engineering Laboratory National University of Defense Technology National Innovation Institute of Defense Technology Academy of Military Science

Aiming at satellite-ground link planning problem for leo satellite navigation augmentation network in the case of multiple ground stations, we proposes a planning method based on graph theory. First, according to the boundary assumption and essential analysis of satellite-ground link planning problem for leo satellite navigation augmentation network in the case of multiple ground stations, we establishes a corresponding mathematical model. Then, based on the need to quickly solve the approximate optimal solution of the above model, a graph theory-based satellite-ground link planning method is proposed, and the performance of the solution result of this method is theoretically proved. Finally, the simulation results verify the effectiveness of the method actually applied to the leo satellite navigation augmentation network in the case of multiple ground stations.

关键词： multiple ground stations leo satellite navigation augmentation satellite-ground link planning

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Precise orbit determination of leo satellite using onboard BDS-3 B1C/B2a observations

Precise orbit determination of LEO satellite using onboard B...

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第十三届中国卫星导航年会

作者： Youcun Wang Qile Zhao Kecai Jiang GNSS Research Center Wuhan University

The precise orbit determination（POD） of low earth orbit（leo） satellites is always a hotspot topic in the field of satellite geodesy. Current gravity field determination, satellite altimetry, and remote sensing measurement depend crucially on the precise orbits of the spacecraft. BeiDou global navigation satellite system（BDS-3） is officially completed in 2020 and offers positioning, navigation, and timing（PNT） service for global users. The onboard BDS measurements from leo satellites can be used for leo POD and served as an effective supplement for BDS tracking geometry. In this study, the BDS-3 observations with B1 C and B2 a signals of HY-2 D spacecraft are employed for reduced-dynamic POD. For superior orbit quality, the extended analytical model for solar radiation pressure（SRP） is used for leo POD, and in-flight calibration of the leo receiver antenna is carried out to improve the orbit precision. Two weeks of onboard BDS-3 observation were used to assess the BDS-based POD performance. For HY-2 D satellite based on BDS-3 instruments, the capability of continuous tracking is at the global level, and almost all the epochs can have 5-7 usable BDS satellites. The average RMS of the phase residual from the reduced-dynamic POD is 6.5 mm, and that of pseudorange residual is 1.28 m. The internal precision for the entire arc is in good agreement. Moreover, an orbit self-consistency of 0.94 cm, 0.76 cm, and 0.49 cm is displayed in the along-track, cross-track, and radial directions, respectively. The average consistency for the reduced-dynamic orbit is at the 1.33 cm position RMS level. BDS-3-based leo orbit determination with the uncertainty of about 2 cm is obtained through independent satellite Laser Ranging（SLR） validation. These results could be used for the Chinese subsequent leo satellite equipped with a BDS-3 receiver.

关键词： BDS-3 leo satellite Precise orbit determination B1C/B2a Orbit precision

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An Optimized Multiple Access Control Protocol for a ’little leo’ satellite Store-and-Forward Global Data Network

An Optimized Multiple Access Control Protocol for a ’little...

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The Fourth International Conference on Parallel and Distributed Computing, Applications and Technologies

作者： Baozhong Cheng Jeff Ward Marting Sweeting School of Electronics and Information Engineering Northern Jiaotong University Surrey Space Center University of SurreySurreyGU2 7XHUK

＜正＞The reservation method used in a TD-SRMA protocol determines the protocol’s efficiency.The typical reservation methods proposed are SALOHA and VCR-SALOHA（Varying Calling Rate SALOHA）. SALOHA is relatively simple to realize but it can not adapt well to the dynamic traffic pattern in a ’little leo’ satellite network.VCR-SAOHA can better adapt the dynamic traffic, but its highest efficiency on average is still 0.38.To improve the reservation efficiency,a new reservation method,AP-SALOHA（Adaptive Polling and SALOHA）,is proposed.In AP-SALOHA,polling is used for the stations which have high probability to upload a message,and SALOHA is used for the stations which have low probability to upload messages.Different from SALOHA and VCR-SALOHA,the length of a reservation period in AP-SALOHA varies according to the network traffic. Analysis and simulation show that AP-SALOHA provides better throughput performance.About 19%improvement over VCR-SALOHA can be achieved.

关键词： Multiple Access Protocol leo satellite

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Method of GNSS Security Augmentation Based on leo satellite

Method of GNSS Security Augmentation Based on LEO Satellite

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第十一届中国卫星导航年会

作者： Tao Yan Ying Wang Xiao Liu Lang Bian Yansong Meng China Academy of Space Technology (Xi’an)

In order to improve the service performance of the global navigation satellite system(GNSS), a variety of augmentationsystems have been developed, including satellite-based and ground-based augmentati

关键词： Security augmentation leo satellite Signal authentication GNSS signals

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