Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View

Small satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced small satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of satellites provide improved spatial and temporal resolution of the target. Small satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-satellite communication is a key aspect when satellites fly in formation. In this paper, we present the various researches being conducted in the small satellite community for implementing inter-satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-satellite communications for multiple small satellite missions. Specific topics include proposed solutions for some of the challenges faced by small satellite systems, enabling operations using a network of small satellites, and some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications Surveys and Tutorial

A Performance Analysis of a Joint LMDS/ Satellite Communication Network

The goal of this research is to provide a performance analysis of a joint terrestrial/ satellite communication network. The systems of interest are the Local Multipoint Distribution Service (LMDS) terrestrial system and the proposed Teledesic satellite network. This analysis is performed using the OPNET network simulation tool. Simulations are run for twelve separate scenarios involving three factors which include: number of users, modulation type, and Quality of Service (QoS). The key metrics for characterizing simulation scenarios are the end-to-end delay, bit error rate, and average system throughput. The results obtained display the benefit of improved throughput, approximately 20 Mbps for the low user load and approximately 8 to 11 Mbps for the high user load, when the modulation schemes where changed. This improvement comes at the expense the bit error rate. For example, the bit error rate increased by a factor of 5 for the low user load when changing from BPSK to QPSK and by a factor of 1.5 for the QPSK to 8-PSK change. The peak end-to-end delay results, ranging from .053 seconds to .446 seconds, proved to support real-time voice communication for all but one scenario (BPSK/ high user load). The QoS proved to be a benefit for scenarios with a high user load (150 users) increasing the average throughput by 2 to 4 Mbps. The QoS also reduced the peak end-to-end delay, narrowing the range from .04 to .104 seconds. The analysis of these three main operational characteristics gives a fundamental look at the joint network\u27s performance capabilities

Low Earth orbit microsatellite constellation utilizing satellite Hellas Sat 5 as a relay

Με δεδομένο ότι βρισκόμαστε σε μια εποχή ορόσημο για την ανάπτυξη στον διαστημικό τομέα, το σύνολο σχεδόν όλων των ανεπτυγμένων χωρών έχει συνειδητοποιήσει ότι η επένδυση στο σύνολο των διαστημικών τεχνολογιών αποτελεί μονόδρομο ανάπτυξης και ευημερίας. Τα δαπανούμενα ποσά είναι απολύτως ενδεικτικά της φρενίτιδας που επικρατεί στη λεγόμενη κούρσα του διαστήματος. Η εισαγωγή πλέον και του ιδιωτικού τομέα στη κούρσα αυτή έχει επιτρέψει την προώθηση του ανταγωνισμού κάτι το οποίο με τη σειρά του έχει ελαττώσει εντυπωσιακά το κόστος χρήσης και αξιοποίησης του διαστημικού τομέα. Αυτό το νέο διαστημικό οικοσύστημα που έχει αναπτυχθεί παγκοσμίως τις τελευταίες δεκαετίες, έχει επιτρέψει τη πρόσβαση στις διαστημικές τεχνολογίες από το σύνολο σχεδόν των χωρών του πλανήτη, τη στιγμή που κατά τις προηγούμενες δεκαετίες, οι μοναδικές χώρες που είχαν τη δυνατότητα να επενδύσουν στον τομέα ήταν οι ΗΠΑ και οι Ρωσία. Δορυφορική παρατήρηση της γης, πλοήγηση, αποτροπή φυσικών καταστροφών, εξερεύνηση του διαστήματος, επιστημονική ανάλυση της επιφάνειας του εδάφους, εκμετάλλευση φυσικών πόρων αλλά και πολιτικές και στρατιωτικές τηλεπικοινωνίες, είναι μόνο μερικές από τις νέες τεχνολογίες που έχει να προσφέρει ο διαστημικός τομέας. Κάθε ένας από αυτούς τους τομείς μπορεί δυνητικά να αποτελέσει πυλώνα ανάπτυξης αν αξιοποιηθεί σωστά και πλέον όλες οι χώρες έχουν συνειδητοποιήσει πως η επένδυση σε κάποιον ή και σε όλους αυτούς τους τομείς μπορούν να επιφέρουν πολλαπλά οφέλη. Ένα χαρακτηριστικό παράδειγμα του νέου διαστημικού οικοσυστήματος που έχει διαμορφωθεί κατά τις τελευταίες δεκαετίες και που δείχνει το πόσο πολύ επενδύουν πλέον οι χώρες στον διαστημικό τομέα, είναι ο υπερδιπλασιαμός των ενεργών δορυφορικών συστημάτων κατά τη πενταετία 2015 – 2020, ιδιαίτερα των τηλεπικοινωνιακών. Αξίζει να σημειωθεί πως τον Δεκέμβριο του 2015, σύμφωνα με τα στοιχεία της UCS, ο αριθμός των ενεργών δορυφόρων του έτους ανήλθε σε 1.381, αριθμός ο οποίος κατά τον ίδιο μήνα του έτους 2020 είχε φτάσει τους 3.372. Έχοντας πει όλα τα παραπάνω, η παρούσα διπλωματική εργασία στοχεύει στην παρουσίαση μιας ολοκληρωμένης ανάλυσης όλων των απαιτούμενων βημάτων που πρέπει να εξετάσει ένας μηχανικός / σχεδιαστής συστημάτων προκειμένου να κατασκευάσει και να αναπτύξει μια πλήρως λειτουργική και αξιόπιστη δορυφορική ζεύξη επικοινωνίας. Η μεθοδολογία περιλαμβάνει μια πλήρη περιγραφή των βασικών νόμων του διαστημικού περιβάλλοντος καθώς και μια εκτενή ανάλυση της τροχιακής μηχανικής και των παραμέτρων. Η ιδέα ήταν να παρουσιαστεί πώς η θεωρία μπορεί να εφαρμοστεί σε μια πραγματική δορυφορική προσομοίωση καθώς και πώς επηρεάζεται από αυτήν. Το τελευταίο βήμα ήταν ο σχεδιασμός και η κατασκευή ενός πραγματικού συστήματος δορυφορικής επικοινωνίας σε ένα εξειδικευμένο λογισμικό και η παρουσίαση των αποτελεσμάτων. Το κύριο συμπέρασμα της παραπάνω υλοποίησης είναι το γεγονός ότι μέσω της χρήσης ενός αστερισμού δορυφόρων χαμηλής Γήινης τροχιάς σε συνδυασμό με έναν γεωστατικό δορυφόρο που χρησιμοποιείται αναμεταδότης, είναι δυνατό να επιτευχθεί μια ανθεκτική και αξιόπιστη επικοινωνιακή ζεύξη με εξαιρετικά υψηλούς ρυθμούς μετάδοσης δεδομένων και σχεδόν παγκόσμια κάλυψη.Given that we are in a landmark era of the space sector development , most countries have realized that an investment in space technologies is the only way for development and prosperity. The invested budgets are absolutely indicative of the so-called space race. The introduction of the private sector in this race has allowed the promotion of competition, which in turn has dramatically reduced the cost of using and exploiting the space sector. This new space ecosystem that has been developed worldwide in recent decades, has allowed access to space technologies from almost all countries on the planet, while in previous decades, the only countries that had the opportunity to invest in the sector were USA and Russia. Satellite earth observation, navigation, prevention of natural disasters, space exploration, scientific analysis of the earth's surface, exploitation of natural resources, but also civil and military telecommunications, are just some of the new technologies that the space sector has to offer. Each of these sectors can potentially be a pillar of development if exploited properly and almost all of the modern countries have realized that investing in one or all of these sectors can offer multiple benefits. A typical example of the new space ecosystem that has been formed during the last decades and that shows how much money countries are now investing in the space sector, is the dramatic increase of the active satellite systems during the years 2015 – 2020, especially the telecommunication ones. It is worth mentioning that in December 2015, according to UCS data, the number of active satellites was 1.381, a number which during the same month in 2020 reached the astonishing number of 3.372. The rapid development of the space sector combined with the cost reducing methods that private sectors have introduced, is showing that the imminent future seems to be very promising. Having said all of the above, this thesis aims at presenting a comprehensive analysis of all the required steps that a system engineer / designer must consider in order to build and deploy a fully functional and reliable satellite communication link. The methodology entails a fully description of the basic laws of the space environment as well as an extensive analysis of the orbital mechanics and parameters. The idea was to demonstrate how the theory can be utilized in an actual satellite project simulation as well as how it is affected by it. The last step was to design and build an actual satellite communication system on a specialized software and present the results. The main conclusion of the above implementation is the fact that through the use of a low Earth orbit satellite constellation combined with a geostationary satellite used as a relay, it’s possible to achieve a resilient and reliable communication link with exceptional high data rates and an almost worldwide coverage

資源に制約のある小型衛星における自由空間光通信に関する研究

Presently, the farthest CubeSats have gone into deep space was via a piggy-back ride to the orbit of planet Mars where a twin-6U CubeSats (MarCO-A & B) in formation provided X-band (8.425GHz) radio-frequency (RF) communication relay support between the Insight Lander spacecraft and the NASA Deep Space Network (DSN) receiving system on Earth at about 8Kbps data rate. Subsequent planned interplanetary CubeSat missions (such as the ESA Asteroid Impact and Deflection Assessment collaborative mission) seeks to leverage on and improve the capacity. The increasing demand for higher network bandwidth and system data-throughput has led to the utilization of higher frequency bands in the electromagnetic spectrum and increase in transmitter power for long range scenarios. Operating at higher frequencies (or shorter wavelengths) provides an expanded channel capacity and reduction in the transceiver components sizes comparable to the lower frequencies (VHF, UHF) counterparts. However, RF signals are highly susceptible to divergent spreading, atmospheric absorption and attenuation, severely limiting the communication system performance and efficiency. The RF spectrum is also fast becoming congested with severe signal interference problems especially in collocated and multi-node systems. On the contrary, the optical bands are currently underexplored, less regulated and without licensing complications. Free-space laser communication represents a paradigm shift in modern high-rate data link and information processing capability enhancement. Laser signals have very high directivity, significantly increasing the transmitter’s effective isotropic radiated power (EIRP) and improving the received signal to noise ratio in a long distance link such as direct deep-space satellite to ground communication system. Compactness of opto-electronic components is likewise attractive for very low-resource (size, weight and power) small satellite platforms, especially CubeSats. On the contrary, the suiting benefits of the narrow laser beamwidth simultaneously give rise to misalignment challenges, pointing and acquisition, tracking (PAT) problems, resulting to pointing errors between the communicating nodes. Platform disturbances and micro-vibrations from satellite onboard subsystems and deployable appendages also contribute to the laser signal pointing instability. A small satellite in deep space establishing an optical link with the ground will require a very strictly precise attitude determination and control system working together with a rapid response beam stabilization system having a high level of reliability and accuracy. Lean or small (commonly used interchangeably) satellite philosophy is gaining prominence in defining the current and future architecture of space exploration missions. In recognition of this, the International Academy of Astronautics constituted a Study Group to define the industry standards and requirements of small satellites. The lean satellite approach seeks cheaper, quick development and delivery of small satellite missions, utilizing commercial-off-the-shelf components, smaller human resource and faster mission turn-around time. CubeSats are getting more roles and are consistently been considered for demanding tasks which were once the domain of traditional satellites. However, there exists a number of technology gaps that must be filled before the full potentials of CubeSat applications for very high throughput missions and deep space exploration can be fully harnessed. Gigabytes rate communication transceivers, compact propulsion system, interplanetary guidance and navigation systems are a few of the current technological gaps. This research is focused on tackling the problems of laser communication adaptability on small satellites in considerable range with Earth-bound optical ground systems. To this end, the systematic design of an example theoretical mission described in this thesis adapts lean satellite initiative, use of COTS components and scalability. A new approach of utilizing Photodiode Array (PDA) as an optical feedback sensor applicable to a MEMS Fine Steering Mirror (FSM) based laser beam fine pointing and control system is introduced in this thesis. Analyses and experiments demonstrated that the PDA have a much improved frame rate, eliminating the feedback delay experienced in the use of CCD cameras for laser beam position control. This presents a useful improvement in the performance of optical beacon tracking and fine pointing systems for laser communication modules in small satellites. Experiments on characterization of platform jitter spectrum and beam steering system mitigating the jitter effects in a 6U CubeSat platform is also presented in this thesis. CubeSats and Unmanned Aerial Vehicles (UAV) are identical in terms of “leanness” or “scarcity” of onboard resources and are both considered as viable host platforms for laser communication devices in a ubiquitous optical communication regime. As a derivation of this research, the activities of the Japanese’ National Institute of Information and Communications Technology, NICT-Kyutech collaboration on the development of a Drone 40Gbps lasercom fine pointing system is discussed. The Drone lasercom project sought to advance the state-of-the-art in UAV communication capabilities, with the agile optical coarse tracking, acquisition and fine pointing system playing a very critical role. In conclusion, the work done and reported in this thesis contributes to the advancement of free-space laser communication technology on small satellites in both near-Earth and deep space scenarios.九州工業大学博士学位論文 学位記番号：工博甲第537号 学位授与年月日：令和3年12月27日1. Introduction |2. Background and Literature Review |3. Lunar Cubesat Lasercom Design Reference Mission |4. Photodiode Array Aided Laser Beam Steering Experiment |5. Cubesat Jitter Effects on Lasercom Beam Pointing Stability |6. Drone 40gbps Lasercom Project |7. Conclusion and Recommendations九州工業大学令和3年

Assessing the technical and financial viability of broadband satellite systems using a cost per T1 minute metric

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, Thesis (S.M.)--Massachusetts Institute of Technology, Technology and Policy Program, 1998.Includes bibliographical references (p. 109-111).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.A cost per 1.544 Mbps (T1) link per minute metric is developed for systems evaluation of satellite based broadband communications systems. Global market models based on Internet growth and computer penetration are developed. Initially systems are limited by the available market, however as the market increases, the design of the system becomes the limiting factor. These limits include satellite power resources, achievable link margins, and rain attenuation. A computer simulation is developed to model the complex interactions between the capacity limits and distributed market models.by Andjelka Kelic.S.M

All-Domain Sensor Network Orchestration from Seabed-to-Space

NPS NRP Technical ReportThe DoD seeks to conduct all-domain operations, requiring Intelligence Surveillance and Reconnaissance (ISR) across all domains of conflict. For the Navy, this uniquely includes the deep seabed, undersea, sea surface, air, space and cyberspace operations. All-Domain ISR encompasses and integrates information from all domains of the maritime environment, sensors and sources from seabed-to-space, to provide commanders with the most complete picture of adversary activities. This capability supports the Navy approach to Distributed Maritime Operations (DMO), an operational concept that enables widely dispersed naval units to perform sensing, command and control and weapon activities such that the distributed platforms act as a coherent whole. All-domain ISR requires a network to enable widely dispersed sensors to exchange and combine sensor data (the fusion of data) to provide a complete understanding of the operational picture, and to provide targeting information for long-range engagement required by DMO. This research studies the diverse sensor access time horizons, sensor mode options, observation feasibilities, and relative contribution of all-domain sensors (seabed-to-space) which pose a significant mathematical and computational challenge to achieve all-domain ISR. Furthermore, the delays from sensing to fusion across such a wide range of sensors can diminish the contribution of some combinations of sensing modes. The study also evaluates the distribution of fusion nodes across an all-domain network to improve the delivery of information across the network.Naval Information Warfare Center Pacific (NIWC Pacific)ASN(RDA) - Research, Development, and AcquisitionThis research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

Adaptation of the IEEE 802.11 protocol for inter-satellite links in LEO satellite networks

Knowledge of the coefficient of thermal expansion (CTE) of a ceramic material is important in many application areas. Whilst the CTE can be measured, it would be useful to be able to predict the expansion behaviour of multiphase materials.. There are several models for the CTE, however, most require a knowledge of the elastic properties of the constituent phases and do not take account ofthe microstructural features of the material. If the CTE could be predicted on the basis of microstructural information, this would then lead to the ability to engineer the microstructure of multiphase ceramic materials to produce acceptable thermal expansion behaviour. To investigate this possibility, magnesia-magnesium aluminate sp~el (MMAS) composites, consisting of a magnesia matrix and magnesium aluminate s~ne'l (MAS) particles, were studied. Having determined a procedure to produce MAS fr alumina and magnesia, via solid state sintering, magnesia-rich compositions wit ~ various magnesia contents were prepared to make the MMAS composites. Further, the l\.1MAS composites prepared from different powders (i.e. from an alumina-magnesia mixture ahd from a magnesia-spinel powder) were compared. Com starch was added into the powder mixtures before sintering to make porous microstructures. Microstructural development and thermal expansion behaviour ofthe MMAS composites were investigated. Microstructures of the MAS and the MMAS composites as well as their porous bodies were quaritified from backscattered electron micrographs in terms of the connectivity of solids i.e. solid contiguity by means of linear intercept counting. Solid contiguity decreased with increasing pore content and varied with pore size, pore shape and pore distribution whereas the phase contiguity depended strongly on the chemical composition and was less influenced by porosity. ' The thermal expansion behaviour of the MAS and the MMAS composites between 100 and 1000 °C was determined experimentally. Variation in the CTE ofthe MAS relates to the degree of spinel formation while the thermal expansion of the MMAS composites depends strongly on phase content. However, the MMAS composites with similar phase compositions but made from different manufacturing processes showed differences in microstructural features and thermal expansion behaviour. Predictions of the CTE values for composites based on a simple rule-of-mixtures (ROM) using volume fraction were compared with the measured data. A conventional ROM accurately predicted the effective CTE of a range of dense alumina-silicon carbide particulate composites but was not very accurate for porous multiphase structures. It provided an upper bound prediction as all experimental values were lower. Hence, the conventional ROM was modified to take account of quantitative microstructural parameters obtained from solid contiguity. The modified ROM predicted lower values and gave a good agreement with the experimental data. Thus, it has been shown that quantitative microstructural information can be used to predict the CTE of multiphase ceramic materials with complex microstructures.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Architectures and synchronization techniques for distributed satellite systems: a survey

Cohesive Distributed Satellite Systems (CDSSs) is a key enabling technology for the future of remote sensing and communication missions. However, they have to meet strict synchronization requirements before their use is generalized. When clock or local oscillator signals are generated locally at each of the distributed nodes, achieving exact synchronization in absolute phase, frequency, and time is a complex problem. In addition, satellite systems have significant resource constraints, especially for small satellites, which are envisioned to be part of the future CDSSs. Thus, the development of precise, robust, and resource-efficient synchronization techniques is essential for the advancement of future CDSSs. In this context, this survey aims to summarize and categorize the most relevant results on synchronization techniques for Distributed Satellite Systems (DSSs). First, some important architecture and system concepts are defined. Then, the synchronization methods reported in the literature are reviewed and categorized. This article also provides an extensive list of applications and examples of synchronization techniques for DSSs in addition to the most significant advances in other operations closely related to synchronization, such as inter-satellite ranging and relative position. The survey also provides a discussion on emerging data-driven synchronization techniques based on Machine Learning (ML). Finally, a compilation of current research activities and potential research topics is proposed, identifying problems and open challenges that can be useful for researchers in the field.This work was supported by the Luxembourg National Research Fund (FNR), through the CORE Project COHEsive SATellite (COHESAT): Cognitive Cohesive Networks of Distributed Units for Active and Passive Space Applications, under Grant FNR11689919.Award-winningPostprint (published version