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1
Wood, Lloyd. "Internetworking with satellite constellations." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/704760/.
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The development and growth of the Internet during the past thirty years has led to demand for and development of Internet services everywhere and over every possible communications medium. This includes the medium of satellite communications. During those same three decades, the growth in use of satellite communications to provide a widely-available wireless communications infrastructure has led to the development of broadband satellite communications using satellite constellation networks. These two technological trends have intersected. Here, we examine networking and internetworking issues affecting satellite networking in complex satellite constellation networks, and determine what is needed in order to support services based on the TCP/IP suite well in satellite constellations. We analyse constellation network topology. Its movement and effects on end-to-end delays experienced by network traffic travelling across the constellation are examined in detail. Analysis of the impact of cross-seam links upon delays experienced by traffic across star constellations shows that the use of cross-seam links is worthwhile. We examine the effects of multi-path routing within the constellation upon TCP communication, and demonstrate the performance advantages of an intelligent flowbased approach to routing in the constellation network. The desirability of implementing IP routing functionality in the space segment of the constellation is shown. The use of IP routing, to enable good support for IP QoS and IP multicast, is shown to be possible. We present an approach to implementing IP multicast within the constellation, evaluating use of a core-based tree algorithm, and outline an architecture permitting IP routing of IP traffic in an ATM-based satellite constellation network, using MPLS. Finally, we present and demonstrate the advantages of a novel method of managing path delay between ground terminals across a rosette constellation with intersatellite links, by using controlled handover to manage surface diversity to provide classes of service to network traffic.
2
Shah, Naresh Harkishan. "Automated station-keeping for satellite constellations." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10514.
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Salazar, Kardozo Alexandros. "A High-Level Framework for the Autonomous Refueling of Satellite Constellations." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14534.
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Satellite constellations are an increasingly attractive option for many commercial and military applications. They provide a robust and distributed method of accomplishing the goals of expensive monolithic satellites. Among the many challenges that satellite constellations engender (challenges in control, coordination, disposal, and other areas), refueling is of particular interest because of the many methods one can use to refuel a constellation and the lifetime implications on the satellites.
The present work presents a methodology for carrying out peer-to-peer refueling maneuvers within a constellation. Peer-to-peer (P2P) refueling can be of great value both in cases where a satellite unexpectedly consumes more fuel than it was alloted, and as part of a mixed refueling strategy that will include an outside tanker bringing fuel to the constellation. Without considering mixed-refueling, we formulate the peer-to-peer refueling problem as an assignment problem that seeks to guarantee that all satellites will have the fuel they need to be functional until the next refueling, while concurrently minimizing the cost in fuel that the refueling maneuvers entail. The assignment problem is then solved via auctions, which, by virtue of their distributed nature, can easily and effectively be implemented on a constellation without jeopardizing any robustness properties.
Taking as a given that the P2P assignment problem has been solved, and that it has produced some matching among fuel deficient and fuel sufficient satellites, we then seek to sequence those prescribed maneuvers in the most effective manner. The idea is that while a constellation can be expected to have some redundancy, enough satellites leaving their assigned orbital slots will eventually make it impossible for the constellation to function. To tackle this problem, we define a wide class of operability conditions, and present three algorithms that intelligently schedule the maneuvers. We then briefly show how combining the matching and scheduling problems yields a complete methodology for organizing P2P satellite refueling operations.
4
Kwok, Kenneth C. H. (Kenneth Chun Hei) 1977. "Cost optimization and routing for satellite network constellations." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8774.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 140-142).
Low-earth orbit (LEO) satellite communications systems have been under rapid development in the past few years as it is predicted that they will become part of the Next Generation Internet (NGI), a global heterogeneous network that provides ubiquitous access to every part of the world. Nevertheless, very little research has been done on the cost aspect of a satellite network. In this thesis, uplink and downlink costs are ignored and a cost equation based solely on crosslinks is developed and studied closely together with a seamless constellation model. Using this cost equation, cost optimization is performed in LEO and GEO satellite systems to find the optimum constellation size with respect to the amount of uniform traffic present. Modifications of the constellations, such as the 3-crosslink-per-node mesh network, and the 1-inter-plane-crosslink mesh network, are introduced in an attempt to further reduce the cost of the system. Interaction of hotspot traffic with uniform traffic in a square mesh is also studied. We are able to find a lower bound and an upper bound of the minimum required crosslink capacity, given a stream of uniform traffic and multiple streams of hot spot traffic. We also find the properties of hot spot traffic in an infinite grid and extend the result to a fixed size grid. Finally, the notion of incorporating the satellite network into the global heterogeneous network is explored. The relationship between the satellite network and the terrestrial network is studied. In particular, the assignment of cost metrics to inter-satellite links, uplinks and downlinks, and terrestrial links is investigated. At the end a basic simulation of the traffic in a heterogeneous network is developed in MATLAB, which can be used to study the transient properties of the network.
by Kenneth C.H. Kwok.
S.M.
5
Holden, Bobby Glenn II. "Onboard distributed replanning for crosslinked small satellite constellations." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122513.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 81-85).
This work implements distributed onboard planning and scheduling approach for crosslinked small satellites Earth observation missions. The example cases used involve 65 small satellites in ISS and Sun Synchronous Orbits, as well as NASA's Near Earth Network groundstations, and three target cases. Target cases include urgent observations. This work focuses on handling dynamic modifications to an existing nominal plan. The disruptions considered include failures to complete an activity and new user requests. The Scheduling Planning Routing Intersatellite Networking Tool, or SPRINT, is the infrastructure used in this work. SPRINT's global planner advances the state of the art by addressing the combinatorially expensive crosslink routing planning challenges, given the constraints of small satellites. SPRINT's distributed onboard planner, the focus of this work, manages both proactive state sharing and reactive planning activities. By introducing robust onboard planning components, high-performance schedules are enabled. An atmospheric model is integrated to provide the SPRINT scenarios. Results are presented for performance of the onboard replanning system. Given arbitrary activity failures, improvement, by means of reduction of the penalty, of 6 to 10 times the unmitigated effects are demonstrated using the onboard planning approach. A path to flight software integration is developed.
NASA Small Spacecraft Technology Program (SSTP)Grant/ Cooperative Agreement Number 80NSSC18M0042
by Bobby Glenn Holden II.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
6
Dhaou, Riadh. "Modélisation de réseaux composés de constellations de satellites." Paris 6, 2002. http://www.theses.fr/2002PA066405.
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Legge, Robert S. Jr. "Optimization and valuation of recongurable satellite constellations under uncertainty/." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/97261.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 303-320).
Space-based persistent surveillance provides decision makers with information necessary to effectively respond to both natural and man-made crises. This thesis investigates a reconfigurable constellation strategy that utilizes on-demand, maneuverable satellites to provide focused regional coverage with short revisit times at greatly decreased cost when compared to traditional static satellite constellations. The thesis develops and demonstrates a general framework to guide the design and optimization of recongurable satellite constellations specifically tailored to stakeholder objectives while considering requirement uncertainty. The framework is novel in that it avoids many of the assumptions and simplifications of past research by: 1. explicitly considering uncertainty in future operating conditions; 2. concurrently optimizing constellation pattern design, satellite design, and operations design; and, 3. investigating layered and asymmetric patterns. The framework consists of three elements: a detailed simulation model to compute constellation performance and cost for a variety of architectures and patterns, Monte Carlo simulation to determine how well each design performs under uncertain future conditions, and a parallel multi-objective evolutionary algorithm developed from the [epsilon]-NSGA-II genetic algorithm to nd designs that maximize performance while simultaneously minimizing cost. Additionally, a new performance metric is developed to measure directly how well a design meets desired temporal and spatial sampling requirements and a decision model and optimal assignment process is developed to determine how to employ the option of reconfigurability to respond to specific regional events. The framework was used to perform 85 optimization runs selected to compare the cost-effectiveness of several constellation architectures over varied operating conditions and coverage requirements. All optimization runs were performed in less than three months, demonstrating that parallel computing coupled with sophisticated optimization routines enable rapid spiral development of satellite constellations. Results show that recongurable constellations cost 20 to 70% less than similarly performing static constellations for the scenarios studied. The cost savings grows with increasingly demanding coverage requirements. Results from optimizing a fully asymmetric constellation pattern led to two the development of new 'quasi'-asymmetric patterns that were found to significantly outperform symmetric patterns for providing discontinuous coverage. Additionally, results show that the sun-synchronous and rapid launch architectures are the least cost-eective approaches.
by Robert Scott Legge Jr.
Ph. D.
8
Kennedy, Andrew Kitrell. "Planning and scheduling for earth-observing small satellite constellations." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120415.
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Thesis: Ph. D. in Space Systems, Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 225-235).
The growth of Earth-observing small satellite constellations requires effective, automated operations management. State-of-the-art techniques must be improved to manage scheduling of observation data collection, data routing through a crosslinked constellation network, and maintenance of limited onboard resources, as well as to enable scaling to hundreds of satellites. This work has four primary contributions. The first is the development of a hierarchical smallsat constellation planning and scheduling system that addresses data routing and resource management. A centralized ground-based algorithm, the Global Planner, manages the whole constellation, while an onboard algorithm, the Local Planner, replans in real-time to handle urgent, unexpected observations. The second contribution is the development of the software infrastructure for simulating the constellation with high fidelity. The third is the analysis of system performance with a set of representative orbit geometries, ground station networks, and communications contexts. The fourth is the demonstration of routing of urgent observation data. The Global Planner algorithm demonstrates execution on larger problem sizes than the state-of-the-art, by quickly executing for both long planning horizons (requiring < 1 minute for a 1000 min. horizon) and many satellites (< 30 mins for 100 sats). Representative constellation geometries are simulated and analyzed with a 6U CubeSat bus model, including a 10-sat Sun-synchronous Orbit Ring and a 30-sat Walker Delta constellation. The improvement using crosslinks in addition to downlinks is assessed over a set of metrics including observation data throughput, latency of data delivery to ground, average Age of Information (freshness) of observation data, and freshness of TT&C data. In every case, performance is found to improve when using crosslinks and downlinks versus only using downlinks. Unplanned, urgent observation data is routed effectively by the Local Planner, achieving comparable latency performance with regular observation data (median of 42 minutes versus 38 mins) in a 6-sat simulation. This work enables efficient scheduling of operations for large, complex smallsat constellations. Future work is discussed that promises further scalability and schedule quality increases from the algorithm architecture presented.
by Andrew Kitrell Kennedy.
Ph. D. in Space Systems
9
Wallace, Scott Thomas. "Parallel orbit propagation and the analysis of satellite constellations." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/46444.
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Santos, Michel. "Improving the coverage of earth targets by maneuvering satellite constellations." College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/7328.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.Thesis research directed by: Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Paek, Sung Wook. "Reconfigurable satellite constellations for geo-spatially adaptive Earth observation missions." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76106.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 145-151).
Continuously increasing demand for Earth observation in atmospheric research, disaster monitoring, and intelligence, surveillance and reconnaissance (ISR) has been met by responsive architectures such as unmanned aerial systems (UAS) or artificial satellites. Space-based architectures can provide non-dominated design solutions on the utility-cost curve compared to alternate architectures through the use of two approaches: (1) reducing satellite manufacturing and launch costs and (2) introducing reconfigurability to the satellite constellations. Reconfigurable constellations (ReCons) enable fast responses to access targets of interest while providing global monitoring capability from space. The wide-area coverage and fast responses provided ReCon can complement high-resolution imagery provided by UAS. A newly proposed ReCon framework improves the model fidelity of previous approaches by utilizing Satellite Tool Kit (STK) simulations and Earth observation mission databases. This thesis investigates the design and optimization of ReCon in low Earth orbits. A multidisciplinary simulation model is developed, to which optimization techniques are applied for both single-objective and multi-objective problems. In addition to the optimized baseline ReCon design, its variants are also considered as case studies. Future work will potentially co-optimize ReCon and UAS-like systems.
by Sung Wook Paek.
S.M.
12
Straub, Alexandra N. (Alexandra Nicole). "Expanded tradespace analysis and operational considerations for reconfigurable satellite constellations." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127090.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 127-131).
Earth observation (EO) satellites provide helpful imagery to a variety of applications ranging from weather monitoring to agricultural support. Disaster response imaging is an essential but difficult application for EO to support. Reconfigurable satellite constellations (ReCon) provide a flexible solution to the challenge of quickly providing imagery of unknown locations. ReCon leverages the natural shift of ground tracks due to the disparity between the Earth's rotation and the period of an orbit to maneuver a constellation into repeating ground track (RGT) orbits. This maneuvering strategy relies on altitude changes to vary an orbit's ascending node and mean anomaly, which both dictate the location of satellite's ground track. Altitude changes require significantly less fuel than plane changes. Using ReCon allows for smaller constellations to provide high-performance imagery for disaster response for a lower cost.
This work explores additional trades for consideration when developing ReCon designs. The following explores satellite image scheduling techniques to further the efficacy of an Earth observation constellation. The scheduler incorporates agile satellites to add imaging targets outside of the satellite's nadir field of view. The ability for a satellite to slew to off-nadir targets is incredibly important when leveraging RGTs. Another design trade considered for ReCon is the propulsion system incorporated on the satellites. Performance and cost trades invoked when using electrical propulsion instead of chemical propulsion are presented within the ReCon framework. This work presents recommendations and future considerations to inform future designers. An investigation into the potential use of staged and responsive launch options further explores flexible options. Using alternative launch strategies allows a program to leverage dropping launch costs and adapt to uncertain imagery demand.
The use of flexible options for EO satellite constellation design is vital in low Earth orbit as satellite technology improves, and space becomes a more crowded domain.
by Alexandra N. Straub.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
13
Luong, Ngoc-Dung. "Analyse d'erreurs de constellations de satellites en termes de positionnement global et d'orbitographie." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4112/document.
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Grâce au développement des techniques spatiales (GNSS, DORIS, laser et le VLBI), la géodésie apporte quantité d’informations sur la forme de la Terre (sa géométrie et sa gravité), sa rotation et son orientation dans l’espace, aux échelles globales comme aux échelles régionales. L’étude des déformations de chaînes de montagne par GPS, des courants marins cartographiés par altimétrie satellitaire, des variations temporelles du champ de gravité, ainsi que l’établissement du repère de référence terrestre international, sont les exemples de l’apport de ces techniques à l’observation de la Terre et au changement global. Notre travail a pour but de faire un bilan des erreurs résiduelles de la géodésie spatiale, en séparant les causes des effets. Le but est de montrer comment les erreurs d’orbite se propagent d’abord dans la trajectoire, puis dans des produits globaux comme le repère de référence (via les mesures de poursuite de satellites) et la surface topographique (via les mesures altimétriques). Nous avons développé une approche analytique qui traite du transfert des erreurs d’origines géométrique et dynamique. En partant des équations du mouvement orbital, nous proposons une solution analytique d’ordre un du mouvement orbital circulaire, qui est appliquée pour propager les erreurs de modèle dynamique. Ensuite, les résultats sont transférés (ou projetés) sur plusieurs types de fonction de mesure : l’altimétrie, les mesures de distance et les mesures de vitesse radiale. L’originalité de ce travail tient pour beaucoup dans les méthodes purement analytiques qui ont été développées spécifiquement pour effectuer les analysesThanks to the development of space techniques (GNSS, DORIS, laser and VLBI) geodesy provides amount of information to determine and to study the shape of the Earth (its geometry and its gravity), its rotation and orientation in space at global scales as well as at regional scales. The study of crustal deformations by using GPS, the ocean topography by satellite altimetry, the temporal variations of the gravity field (mass transports) as well as the construction and monitoring of the International Terrestrial Reference Frame (ITRF), are some examples of the contribution of these techniques to the Earth observation including the current global change. Our work aims to separate causes and consequences. We developed a dedicated approach in which different source of errors, of geometrical and dynamical natures, are treated by analytical expressions. Starting from the dynamical satellite equation of motion, we propose to integrate and propagate the model errors and then to project the results into different measurement functions: altimetry, tracking distances and radial velocities. It results in a complex but comprehensive way that enables the propagation of prediction errors into some general geodetic products as the terrestrial reference frame or the ocean surface topography. The originality of this work lies in the development of a purely analytical method for circular orbits, which has been used to propagate errors from dynamical models. In addition, the resulting orbit errors were projected at the measurement level in order to deduce the impacts on some global geodetic products
14
Bau, Jason H. (Jason Hsi-Chieh) 1978. "Topologies for satellite constellations in a cross-linked space backbone network." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/38441.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 101).
An evolutionary space data network can be formed from satellites serving as both backbone and user-access nodes connected via high-speed cross-links. Such a space backbone network should support spacecraft-to-ground and spacecraft-to-spacecraft links for users of various altitudes (LEO, MEO, GEO and HEO). One main consideration in the design of such a space network is the physical altitude and topology of the backbone satellite constellation. In this thesis, different GEO, MEO, and LEO configurations are considered as backbone topologies to serve the projected user altitudes and requirements. First, exact constellations are determined for each proposed configuration that meet the user coverage requirements while maximizing coverage efficiency. The complexities of these constellations are then compared using constellation parameters such as altitude, and the number of orbital planes required, and the number of satellites required per plane, as well as individual satellite parameters like the number of antennae required, the necessary slewing rate of each antenna, the power required by each antenna, and the physical placement of these antennae on the satellites. The complexity parameters of each individual satellite will be determined for two of the types of communications links used on the satellite, namely links between the user satellites and backbone satellites and links between backbone satellites. These parameters are then used in a speculative cost model to determine the cost versus complexity of each constellation. Through these calculations, a GEO backbone consisting of three satellites is determined to require a minimum number of apertures for both types of links as well as allowing an optimal onboard placement of these apertures. Thus, it possesses cost vs. complexity characteristics superior to other constellations and should be the choice for a space-borne data backbone network.
by Jason H. Bau.
M.Eng.
15
Walker, Roger. "The long-term interactions of satellite constellations with the orbital debris environment." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310852.
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Bruccoleri, Christian. "Flower constellation optimization and implementation." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2404.
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Chaize, Mathieu 1980. "Enhancing the economics of satellite constellations via staged deployment and orbital reconfiguration." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/28285.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2003.Includes bibliographical references (p. 171-175).
The "traditional" way of designing constellations of communications satellites is to optimize the design for a specific global capacity. This approach is based on a forecast of the expected number of users and their activity level, both of which are highly uncertain. It can lead to economic failure if the actual demand is smaller than the one predicted. This thesis presents an alternative approach to the design process to reduce the economic risks. It proposes to deploy constellations in a staged manner, starting with a smaller, more affordable capacity that can be increased if necessary. When the capacity is increased, additional satellites have to be launched and the existing constellation needs to be reconfigured on orbit. Technically, it implies that particular design elements are initially embedded in the design to allow the reconfiguration. Such elements are called "real options" and give decision makers the right but not the obligation to increase the capacity of the system after its initial deployment. This approach reframes the design objectives. Instead of determining an optimal design for a specific capacity, paths of architectures are sought in the trade space. A general framework is presented to identify the paths that offer the most flexibility given different demand scenarios. It is then applied to LEO constellations of communications satellites. Improvements in the life cycle costs on the order of 30% can be obtained for different discount rates and volatilities. This value of flexibility has to be compared to the actual price of the real options. A general method is proposed to study this problem and two technical solutions are proposed.
by Mathieu Chaize.
S.M.
18
Kormos, Tamas. "Dynamics and control of satellite constellations and formations in low earth orbit." Thesis, University of Surrey, 2004. http://epubs.surrey.ac.uk/844273/.
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The topic of this research focuses on developing analytic models, simulations and relative orbit control for multiple spacecraft in constellations or formations in Low Earth Orbits (LEO). The motivation for this research lies in the recent development and focus on describing the relative motions of spacecraft flying in LEO and also the numerous advantages proposed formation flying missions could provide. Since the complexity of modelling, the dynamics and executing control on a group of satellites is far greater than that of one satellite, this research only investigates a small number of very specific problems in this area. The focus of the approach is to develop the orbit modelling of a single satellite, to describe the relative motion of multiple satellites in neighbouring orbits, using the analytical epicycle equations. The first part of the thesis focuses on the problem of formation and constellation assembly, where inclination differences in the initial conditions causes drift in the relative phases of the satellites. After deriving an analytical model and executing firings, real world data is shown to prove the accuracy of the method. In the second part, the modelling of relative orbits of kilometre-sized satellite formations is investigated. Such formations could only be viable if accurate description and prediction of the relative orbits of the spacecraft is available. The analytic formulation also gives a better understanding of ways to establish formations and maintain them with the least fuel requirement. Finally, in the third part, the orbit acquisition, phasing and maintenance of constellations of satellites is discussed in the context of Surrey's Disaster Monitoring Constellation. The centralized control scheme allows for global optimization and fuel balancing algorithms, which can also be used for formation flying as well. The results presented show that small satellite formations and constellations benefit significantly from an analytical description. Reformulating the epicycle equations for multi-satellite applications provides satisfactory accuracy for most small satellite formation missions. Key words: spacecraft formation flying, satellite constellations, epicycle.
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Smith, James Earl 1973. "Application of optimization techniques to the design and maintenance of satellite constellations." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/32695.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1999.Vita.
Includes bibliographical references (p. 401-406).
Optimization techniques were studied and applied to a variety of applications in both the design and maintenance of satellite constellations. Powell's method and parallel genetic algorithms were used in conjunction with precise orbit propagation schemes to develop robust orbit optimization tools. Specifically, local and global optimization methods were used to design a 113:14 repeat ground track variant of the Ellipso TM inclined elliptical sub-constellation and a gear array variant of the Ellipso TM equatorial sub-constellation. The resulting optimal constellation designs were found to maintain stability, even when subjected to full perturbation analysis. The global optimization technique of parallel genetic algorithms was also used to create an optimization approach capable of maintaining the designed orbits over specified lengths of time. Although the global method proved successful over short time periods, limitations of the approach eliminated longer time span optimizations and led to the creation of a more operational station-keeping optimization scheme. The more operational station-keeping implementation yielded similar station-keeping estimates while allowing for the study of longer time periods.
by James Earl Smith.
S.M.
20
Budianto, Irene Arianti. "A collaborative optimization approach to improve the design and deployment of satellite constellations." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/12384.
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Chang, Darren Datong 1977. "Quantifying technology infusion and policy impact on low earth orbit communication satellite constellations." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17759.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2004.Includes bibliographical references (p. 199-204).
Technology infusion and policy implementation bring impacts to the trade space of complex engineering systems. This work describes in detail the frameworks for quantitative analyses on these impacts, demonstrates their use on the sample system, and presents the analysis results. The low earth orbit (LEO) communication satellite constellation system serves as the platform for carrying out the system trade space analysis. The system is reproduced in computer environment in the form of a multiple-input-output MATLAB model. The model contains multiple modules that incorporate the physics, economy, and policies of the real-world system. The inputs to the model are system design variables and the outputs are system performance, capacity, and cost. The Pareto optimal solution set of the baseline trade space is generated by the model using a full-factorial run that covers the entire design space. To simulate technology infusion, technical and cost attributes of four new technologies are quantified and infused into the system model. The infusion of technologies and combinations of technologies into the system is simulated. Policy implementation is simulated by changing the policy constraints in the model. The technology-infused trade space and policy-implemented trade space have new sets of Pareto optimal solutions. By comparing these solution sets with the baseline optimal solution set in the objective space, we can quantify the impact of technology infusion and policy impact. In conclusion, the methodologies of quantifying the impact of technology infusion and policy implementation on complex engineering systems is repeatable and has been tested against real-world systems.
(cont.) The information generated demonstrates their usefulness to technology selection and policy decision-making processes.
by Darren Datong Chang.
S.M.
22
Sun, Jun 1975. "Capacity provisioning, failure recovery and throughput analysis for low earth orbit satellite constellations." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16892.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 85-87).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
We investigate the capacity needed to build a restorable satellite network and design routing schemes to achieve high throughput. Specifically, the first part of this thesis considers the link capacity requirement for a LEO satellite constellation. We model the constellation as an N x N mesh-torus topology under a uniform all-to-all traffic model. Both primary capacity and spare capacity for recovering from a link or node failure are examined. In both cases, we use a method of \cuts on a graph" to obtain lower bounds on capacity requirements and subsequently find algorithms for routing and failure recovery that meet these bounds. Finally, we quantify the benefits of path based restoration over that of link based restoration; specifically, we find that the spare capacity requirement for a link based restoration scheme is nearly N times that for a path based scheme. In the second part of this thesis, we consider a packet switching satellite network in which each node independently generates packets with a fixed probability during each time slot. With a limited number of transmitters and buffer space onboard each satellite, contention for transmission inevitably occurs as multiple packets arrived at a node. We consider three routing schemes in resolving these contentions: Shortest Hops Win, Random Packet Win and Oldest Packet Win; and evaluate their performance in terms of throughput. Under no buffer case, the throughput of the three schemes are significantly different. However, there is no appreciable difference in the throughput when buffer is available at each node. Also, a small buffer size at each node can achieve the same throughput performance as that of infinite buffer size. Simulations suggests that our theoretical throughput analysis is very accurate.
by Jun Sun.
S.M.
23
Burlacu, Maria-Mihaela. "Analyse des performances et routage dans les constellations de nano-satellites : modèles et applications pour les régions éloignées." Phd thesis, Université de Haute Alsace - Mulhouse, 2010. http://tel.archives-ouvertes.fr/tel-00608660.
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La réduction des budgets du domaine spatial et les missions scientifiques traditionnelles ayant des coûts et une complexité croissants a amené la communauté scientifique à se concentrer sur les petits satellites qui fournissent non seulement des résultats scientifiques de valeur, mais permettent aussi de nouvelles applications dans le domaine de la télédétection, de la surveillance environnementale et des télécommunications. De plus, le concept de vol en formation de petits satellites est une technologie-clé pour beaucoup de missions spatiales futures, en améliorant la capacité de survie et réduisant le coût des missions. Ce travail de recherche a un double but : la proposition de modèles innovants de constellations de nano-satellites et de nouvelles approches de routage pour les réseaux de nano-satellites. Cette thèse propose et analyse trois modèles de constellations de nano-satellites dénommés NanoDREAM, NanoiCE et NanoSPHERE, qui fournissent des services de télécommunications aux régions éloignées. Le modèle NanoDREAM est conçu pour le Désert Salar de Uyuni en Bolivie, une région qui détient 70% de la réserve mondiale de lithium. Le modèle NanoiCE est destiné aux Régions Polaires, pour satisfaire les besoins de télécommunications de la communauté scientifique. Le modèle NanoSPHERE est conçu pour fournir une couverture globale de la Terre pour un marché de télécommunications concurrentiel. De plus, nous avons proposé une architecture pour le segment terrestre basée sur la technologie sans fil. Cette architecture a été déployée sur la zone d'exploitation du Désert Salar de Uyuni. Ces modèles ont été développés analytiquement et mis ensuite en œuvre dans le simulateur SaVi afin d'identifier la meilleure constellation satisfaisant les requis de la mission en terme de couverture et en réduisant au minimum le nombre de nano-satellites de la constellation. [...]
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Dutta, Atri. "Optimal cooperative and non-cooperative peer-to-peer maneuvers for refueling satellites in circular constellations." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28082.
Full textAbstract:
Thesis (M. S.)--Aerospace Engineering, Georgia Institute of Technology, 2009.Committee Chair: Panagiotis Tsiotras; Committee Member: Eric Feron; Committee Member: Joseph Saleh; Committee Member: Ryan Russell; Committee Member: William Cook
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Foreman, Veronica L. (Veronica Lynn). "Emergence of second-generation low earth orbit satellite constellations : a prospective technical, economic, and policy analysis." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119297.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018.Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy Program, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 133-145).
Modern proposals for Low Earth Orbit (LEO) satellite constellations underscore the tremendous potential and versatility of distributed spacecraft missions (DSMs), but they have also begun to stress the limits of the existing development paradigm. A new generation of LEO constellations is emerging, and understanding the related technical, economic, and policy landscapes will be critical to fostering their success. The most significant value of this research effort comes from its breadth. LEO constellations are becoming essential tools for a wide range of applications, and this work seeks to examine the diverse set of topics facing modern constellation stakeholders. Through a multidisciplinary, systems engineering evaluation, this thesis synthesizes current knowledge gaps and questions related to second-generation LEO constellations. The investigation begins with a discussion of the historical development of DSMs, and three distinct eras of constellation use are identified. The initial time period, 1959 to 1996, captures the early DSMs that framed the development of modern systems. The first generation spans from 1997 to 2009. It begins with the installation of the first commercial, telecommunications constellations and demonstrates logistic growth for commercial DSM member spacecraft. Growth rates surge again as the second generation begins in 2010, and the data reflect current trends toward commercial, remote-sensing applications of DSM systems. The second generation of LEO constellations coincides with an approximately 189% increase in the annual NGSO satellite launch rate and a 92% increase in the number of constellation systems initialized each year over the first generation. This work continues by underscoring technologies that have enabled this growth through a survey of relevant literature and patent filings. Contemporary issues in constellation technology policy are also examined. Through a series of cost and risk focused case studies, limitations within the existing development and maintenance paradigms are illustrated. The new generation of constellations is challenging the assumptions that have traditionally guided such analyses, and opportunities for further framework development are discussed. This thesis represents a contribution to the advancement of constellation systems by assessing the viability of the existing paradigm and identifying critical areas of future research.
Supported by the National Science Foundation Graduate Research Fellowship Grant No. 1122374
by Veronica L. Foreman.
S.M.
S.M. in Technology and Policy
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Du, Toit Daniel N. J. "Low Earth orbit satellite constellation control using atmospheric drag." Thesis, Link to the online version, 1997. http://hdl.handle.net/10019/2999.
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Bonnet, Jonathan. "Multi-criteria and multi-objective dynamic planning by self-adaptive multi-agent system, application to earth observation satellite constellations." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30058/document.
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Etablir le meilleur plan pour l'usinage d'un produit, le meilleur ordonnancement des activités de construction d'un bâtiment ou la meilleure tournée de véhicules pour la livraison des commandes, en prenant en compte diverses contraintes économiques, temporelles, humaines, ou même météorologiques : dans cette diversité d'applications, optimiser la planification est une tâche complexe par le grand nombre d'entités hétérogènes en interaction, la forte dynamique, les objectifs contradictoires à atteindre, etc. La planification de missions pour des constellations de satellites en est un exemple majeur : beaucoup de paramètres et de contraintes, souvent antagonistes, doivent être pris en compte, entraînant une importante combinatoire. Actuellement, en Europe, les plans de missions sont élaborés au sol, juste avant que le satellite ne soit visible par la station d'émission. Les requêtes arrivant durant la planification ne peuvent être traitées, et sont mises en attente. De plus, la complexité de ce problème croit drastiquement : le nombre de constellations et les satellites les composant augmentent, ainsi que le nombre de requêtes journalières. Les approches actuelles montrent leurs limites. Pour pallier à ces inconvénients, de nouveaux systèmes basés sur la décentralisation et la distribution inhérentes à ce genre de problèmes, sont nécessaires. La théorie des systèmes multi-agents adaptatifs (AMAS) et notamment le modèle AMAS4Opt (AMAS for Optimisation) ont montré leur adéquation pour la résolution de problèmes d'optimisation complexes sous contraintes. Le comportement local et coopératif des agents AMAS permet au système de s'auto-adapter à la forte dynamique et de fournir des solutions adéquates rapidement. Dans cette thèse, nous adressons la résolution de la planification des missions de satellites par AMAS. Pour cela, nous avons complété et enrichi les modèles d'agents proposés par AMAS4Opt. Nous avons ainsi développé le système de planification dynamique de missions ATLAS. Pour valider ATLAS sur divers critères, nous avons utilisé un grand nombre de données hétérogènes. Enfin, ce travail a été comparé à un système " opérationnel' " standard sur des scénarios réels, mettant en valeur les apports de notre systèmeBuilding the best plan in product treatment, the best schedule to a building construction or the best route for a salesman in order to visit a maximum of cities in the time allowed while taking into account different constraints (economic, temporal, humans or meteorological ): in all of those variety of applications, optimizing the planning is a complex task including a huge number of heterogeneous entities in interaction, the strong dynamics, multiple contradictory objectives, etc. Mission planning for constellations of satellites is a major example: a lot of parameters and constraints, often antagonists must be integrated, leading to an important combinatorial search space. Currently, in Europe, plans are built on ground, just before the satellite is visible by the ground stations. Any request coming during the planning process must wait for the next period. Moreover, the complexity of this problem grows drastically: the number of constellations and satellites increases, as the number of daily requests. Current approaches have shown their limits. To overcome those drawbacks, new systems based on decentralization and distribution inherent to this problem, are needed. The adaptive multi-agent systems (AMAS) theory and especially the AMAS4Opt (AMAS For Optimization) model have shown their adequacy in complex optimization problems solving. The local and cooperative behavior of agents allows the system to self-adapt to highly dynamic environments and to quickly deliver adequate solutions. In this thesis, we focus on solving mission planning for satellite constellations using AMAS. Thus, we propose several enhancement for the agent models proposed by AMAS4Opt. Then, we design the ATLAS dynamic mission planning system. To validate ATLAS on several criteria, we rely on huge sets of heterogeneous data. Finally, this work is compared to an operational and standard system on real scenarios, highlighting the value of our system
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Pegher, Douglas J. "Optimizing coverage and revisit time in sparse Military satellite constellations : a comparison of traditional approaches and genetical algorithms /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FPegher.pdf.
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Pegher, Douglas J. Parish Jason A. "Optimizing coverage and revisit time in sparse military satellite constellations : a comparison of traditional approaches and genetic algorithms /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FPegher.pdf.
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Parish, Jason A. "Optimizing coverage and revisit time in sparse military satellite constellations a comparison of traditional approaches and genetic algorithms." Thesis, Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1209.
Full textAbstract:
Sparse military satellite constellations were designed using two methods: a traditional approach and a genetic algorithm. One of the traditional constellation designs was the Discoverer II space based radar. Discoverer II was an 8 plane, 24 satellite, Low Earth Orbit (LEO), Walker constellation designed to provide high-range resolution ground moving target indication (HRR-GMTI), synthetic aperture radar (SAR) imaging and high resolution digital terrain mapping. The traditional method designed 9-ball, 12-ball, 18-ball, and 24- ball Walker constellations. The genetic algorithm created constellations by deriving a phenotype from a triploid genotype encoding of orbital elements. The performance of both design methods were compared using a computer simulation. The fitness of each constellation was calculated using maximum gap time, maximum revisit time, and percent coverage. The goal was to determine if one design method would consistently outperform the other. The genetic algorithm offered a fitness improvement over traditional constellation design methods in all cases except the 24-ball constellation where it demonstrated comparable results. The genetic algorithm improvement over the traditional constellations increased as the number of satellites per constellation decreased. A derived equation related revisit time to the number of ship tracks maintained.US Navy (USN) author.
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Restrepo, Mejia Joaquin. "Analyse comparative entre constellations de satellites en orbite basse (cellules rattachees au satellite et cellules fixes au sol) pour un service simultane a des usagers fixes et mobiles." Paris : Ecole nationale supérieure des télécommunications, 1997. http://catalogue.bnf.fr/ark:/12148/cb37024902w.
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Walton, M. Patrick. "Concepts for Rapid-refresh, Global Ocean Surface Wind Measurement Evaluated Using Full-System Parametric Extrema Modeling." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9157.
Full textAbstract:
Satellite wind vector data is integral to atmospheric models and forecasts. Currently, the limited refresh rate of global wind vector measurement systems makes it difficult to observe diurnal variation of mesoscale processes. Using advancements in the underlying subsystem technologies, new satellite wind scatterometers may be possible that increase temporal resolution, among other performance metrics. I propose a method for parametrically modeling the extreme performance range of a complex system. I use this method to develop a model of the space of possible satellite wind scatterometer designs. I validate the model using point designs of heritage scatterometers. Finally, I present two example concepts for constellations of cooperative satellite wind scatterometers capable of measuring global ocean surface vector winds every hour for the same total cost as a single heritage scatterometer.
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Dainty, Benjamin G. "Use of two-way time transfer measurements to improve geostationary satellite navigation :." Ft. Belvoir Defense Technical Information Center, 2007. http://handle.dtic.mil/100.2/ADA472457.
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Scialom, Uriel 1978. "Optimization of satellite constellation reconfiguration." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/82803.
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Parker, Melahn Lyle 1979. "Broadband satellite constellation design & evaluation." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/81807.
Full textAbstract:
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001.Pages 145-150 are folded and numbered as leaves.
Includes bibliographical references (p. 175-179).
by Melahn Lyle Parker.
M.Eng.
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Kiremitci, Huseyin. "SATELLITE CONSTELLATION OPTIMIZATION FOR TURKISH ARMED FORCES." Monterey, California. Naval Postgraduate School, 2013. http://hdl.handle.net/10945/32849.
Full textAbstract:
Advancing technologies in smallsats provide remote sensing and communications capabilities achievable with a constellation of satellites at a reasonable cost to meet military needs. Like any other nation looking for a cheap but effective solution in that area, Turkey might also benefit from a replacement of its remote sensing assets. Currently Turkish Armed Forces rely on a limited number of reconnaissance aircraft and Unmanned Aerial Vehicles, which do not provide real-time or near real-time remote sensing capabilities. Near real-time remote sensing needs for the Turkish warfighter dictates Turkish Armed Forces reach that capability as soon as possible. Likewise, replacing its conventional communication radios with satellite communication devices would also fulfill warfighter needs. While current communication devices have physical limitations in Turkeys mountainous terrain and the surrounding seas, satellite communication capability would provide wider coverage and for specific frequencies might provide better resistance to jamming and interference too. For the benefit of Turkish Armed Forces communications needs, a satellite constellation must be optimized such that effective coverage will be achieved with the least number of satellites to provide a reasonable cost. In this study, Satellite constellation optimization for the Turkish Armed Forces will be achieved by using Analytical Graphics, Inc.s Systems Tool Kit software for simulation and analysis of several possible communications and remote sensing satellite constellations covering Turkish territory and surrounding seas.
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Eves, S. "Figure of merit for satellite constellation design." Thesis, Cranfield University, 2002. http://dspace.lib.cranfield.ac.uk/handle/1826/11255.
Full textAbstract:
The purpose of this research has been to develop a technique by which satellite
constellations in different classes of orbit may be realistically compared. Previous work on
constellation design has tended to focus on minimising the number of satellites required to
provide coverage of the Earth. The variations in satellite vehicle design, which result from
the use of different orbits, have, in general, been neglected in such analyses. The purpose of
this research is to bridge this gap between constellation design and satellite design using a
Figure of Merit.
This Figure of Merit incorporates the coverage value provided by the satellite
constellation, measured in terms of percentage coverage time, and the overall mass of the
satellites which are required to provide this coverage.
The coverage value is measured against a specific requirement, which is defined
geographically, and which may be weighted by the user to reflect the relative importance of
different regions. This allows arbitrary, asymmetric, real-world requirements to be
adequately represented. This also marks something of a departure from previous work, in
that the goal of much constellation design work has been to provide un-weighted coverage of
the entire globe.
Simplified mass models are developed for generic communications and surveillance
satellites in a variety of orbits, and are then used to calculate the Figure of Merit for
individual satellites.
It is shown that the best solution depends crucially upon the geographical distribution
of the requirement, and other user-defined parameters, such as the minimum elevation angle
which can be tolerated. It is also shown that, for certain typical requirements, the Figure of
Merit correctly identifies geostationary orbit (GEO) and low Earth orbit (LEO) as having
particular advantages.
iii
The technique of characterising the requirement geographically may also be used as a
means of optimising the orbital parameters of the candidate constellations, and a preliminary
description of this procedure is also provided.
The Figure of Merit Technique is then applied to representative communications
satellite constellations in order to demonstrate its ability to differentiate between candidate
options.
The Figure of Merit technique is also used to investigate the possibility of using a
surveillance satellite at very low altitudes.
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Lee, Soung Sub. "Dynamics and Control of Satellite Relative Motion: Designs and Applications." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26661.
Full textAbstract:
This dissertation proposes analytic tools for dynamics and control problems in the perspective of large-scale relative motion without perturbations. Specifically, we develop an exact and efficient analytic solution of satellite relative motion using a direct geometrical approach in spherical coordinates. The resulting solution is then transformed into general parametric equations of cycloids and trochoids. With this transformation, the dissertation presents new findings for design rules and classifications of closed and periodic parametric relative orbits. A new observation from the findings states that the orbit shape resulting from the relative motion dynamics of circular orbit cases in polar views are exactly the same as the parametric curves of cycloids and trochoids. The dynamics problem of satellite relative motion is expanded to include the design of satellite constellations for multiple satellite systems. A Parametric Constellation (PC) is developed to create an identical constellation pattern, or repeating space track, of target satellites with respect to a base satellite. In this PC theory, the number of target satellites is distributed using a real number system for node spacing. While using a base satellite orbit as the rotating reference frame, the PC theory consists of satellite phasing rules and closed form formulae for designing repeating space tracks. The evaluation of the PC theory is illustrated through it’s comparison to the existing Flower Constellation theory in terms of node spacing distribution and constellation design process. For the control problems, the efficient analytic solution is applied to the reference trajectory of satellite relative tracking control systems for inter-satellite links. Two types of relative tracking control systems are developed and each is evaluated to determine which is more appropriate for practical applications of inter-satellite links. All of the proposed analytic solutions and tools in this dissertation will be useful for the mission analysis and design of relative motions involving a two or more satellite system.Ph. D.
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Eves, Stuart. "A figure of merit for satellite constellation design." Thesis, Cranfield University, 2002. http://dspace.lib.cranfield.ac.uk/handle/1826/11255.
Full textAbstract:
The purpose of this research has been to develop a technique by which satellite constellations in different classes of orbit may be realistically compared. Previous work on constellation design has tended to focus on minimising the number of satellites required to provide coverage of the Earth. The variations in satellite vehicle design, which result from the use of different orbits, have, in general, been neglected in such analyses. The purpose of this research is to bridge this gap between constellation design and satellite design using a Figure of Merit. This Figure of Merit incorporates the coverage value provided by the satellite constellation, measured in terms of percentage coverage time, and the overall mass of the satellites which are required to provide this coverage. The coverage value is measured against a specific requirement, which is defined geographically, and which may be weighted by the user to reflect the relative importance of different regions. This allows arbitrary, asymmetric, real-world requirements to be adequately represented. This also marks something of a departure from previous work, in that the goal of much constellation design work has been to provide un-weighted coverage of the entire globe. Simplified mass models are developed for generic communications and surveillance satellites in a variety of orbits, and are then used to calculate the Figure of Merit for individual satellites. It is shown that the best solution depends crucially upon the geographical distribution of the requirement, and other user-defined parameters, such as the minimum elevation angle which can be tolerated. It is also shown that, for certain typical requirements, the Figure of Merit correctly identifies geostationary orbit (GEO) and low Earth orbit (LEO) as having particular advantages. iii The technique of characterising the requirement geographically may also be used as a means of optimising the orbital parameters of the candidate constellations, and a preliminary description of this procedure is also provided. The Figure of Merit Technique is then applied to representative communications satellite constellations in order to demonstrate its ability to differentiate between candidate options. The Figure of Merit technique is also used to investigate the possibility of using a surveillance satellite at very low altitudes.
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Grandchamp, Enguerran. "Quelque contribution à l'optimisation de constellations de satellites." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2001. http://tel.archives-ouvertes.fr/tel-00634769.
Full textAbstract:
A mi-chemin entre l optimisation et l astronautique ce travail de recherche s attaque au problème du design de constellations de satellites Déterminer le nombre de satellites nécessaires pour ré- pondre à un besoin et les positionner de manière correcte tels sont les enjeux techniques de cette thèse Minimiser les coûts et les délais tels sont les enjeux économiques auxquels est confronté le domaine spatial au quotidien Les difficultés majeures de ce problème sont d une part la taille et les caractéristiques de l espace de recherche; D autre part la non-régularité des critères utilisés et la nature mathématique et phy- sique hétérogène de l ensemble des paramètres (paramètres entiers et paramètres réels) interdisant l utilisation d algorithmes classiques; Enfin l évaluation des solutions qui met en oeuvre une simu- lation coûteuse en temps et en calculs sans retourner d information pertinente sur les bonnes ou mauvaises propriétés de la constellation évaluée interdit une exploration massive de l espace de recherche De ces constatations et de diverses études préliminaires est née une nouvelle approche Basé sur une meilleure exploitation de la simulation et sur une simplification des critères utilisés l algorithme composé de plusieurs niveaux met en oeuvre plusieurs techniques d optimisation En intégrant une base de connaissance sur les orbites et une méthode numérique de recherche d optimum le tout or- chestré par un algorithme métaheuristique cette nouvelle approche tente de résoudre les difficultés intrinsèques au domaine d application en décomposant le problème.
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Boukhatem, Lila. "Le handover dans les constellations de satellites LEO." Paris 6, 2001. http://www.theses.fr/2001PA066501.
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Grandchamp, Enguerran. "Quelques contributions pour l'optimisation de constellations de satellites." Toulouse, INPT, 2001. http://www.theses.fr/2001INPT045H.
Full textAbstract:
A mi-chemin entre l'optimisation et l'astronautique, ce travail de recherche s'attaque au problème du design de constellations de satellites. Déterminer le nombre de satellites nécessaires pour répondre à un besoin et les positionner de manière correcte, tels sont les enjeux techniques de cette thèse. Minimiser les coûts et les délais, tels sont les enjeux économiques auxquels est confronté le domaine spatial au quotidien. Les difficultés majeures de ce problème sont : d'une part la taille et les caractéristiques de l'espace de recherche; D'autre part la non-régularité des critères utilisés et la nature mathématique et physique hétérogène de l'ensemble des paramètres (paramètres entiers et paramètres réels) interdisant l'utilisation d'algorithmes classiques; Enfin l'évaluation des solutions qui met en oeuvre une simulation coûteuse en temps et en calculs sans retourner d'information pertinente sur les bonnes, ou mauvaises, propriétés de la constellation évaluée interdit une exploration massive de l'espace de recherche. De ces constatations et de diverses études préliminaires est née une nouvelle approche. Basé sur une meilleure exploitation de la simulation et sur une simplification des critères utilisés, l'algorithme composé de plusieurs niveaux met en oeuvre plusieurs techniques d'optimisation. En intégrant une base de connaissance sur les orbites et une méthode numérique de recherche d'optimum,le tout orchestré par un algorithme métaheuristique, cette nouvelle approche tente de résoudre les difficultés intrinsèques au domaine d'application en décomposant le problème.
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Wilkins, Matthew Paul. "The Flower Constellations - theory, design process, and applications." Texas A&M University, 2004. http://hdl.handle.net/1969.1/3053.
Full textAbstract:
In this research, constellations of satellites all having orbits compatible with rotating
reference frames are considered. That is to say, no matter how many satellites are considered
for the constellation, when viewed from an arbitrarily defined rotating reference frame
of interest, they all follow a single, identical relative trajectory. In this regard, one could
think of the relative trajectories as ?space trajectories on a rotating reference frame.?
In particular, this research concerns itself with reference frames constrained to rotate
with the planet under consideration (e.g. the Earth Centered Earth Fixed (ECEF) frame,
a frame rotating with the Earth). When the axis of symmetry of these constellations is
aligned with the spin axis of the planet, then the ground track as projected onto the planet
surface will be repeating.
Flower Constellations are identified by eight parameters. Five are integer parameters:
the number of petals (Np), the number of sidereal days to repeat the ground track (Nd), the
number of satellites (Ns), and two integers to govern the phasing (Fn and Fd). Three are
orbit parameters that are generally equal for all satellites: the argument of perigee (w), the
orbit inclination (i), and the perigee altitude (hp). Each of these parameters has a unique effect on the overall design of a Flower Constellation. Based upon specific choices of these parameters, some broad categories of constellation types are presented along with some unique cases. Often, a large number of satellites are used to completely visualize these constellations. While Flower Constellations lend themselves to micro- and nano-satellite constellations very easily, they are also readily scalable to any mission requirement. Also investigated are inverse design techniques where the governing equations are solved for the Flower Constellation parameters to achieve a desired final constellation or formation shape. Flower Constellations present beautiful and interesting dynamical features that allow us to explore a wide range of potential applications that include: telecommunications, Earth and deep space observation, global positioning systems, and new kinds of formation flying schemes among others. To demonstrate their potential, some specific Flower Constellations are described and discussed. Finally, the effect of perturbations such as the Earth?s oblateness are investigated and options for mitigating perturbations are discussed.
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Bonnet, Grégory. "Coopération au sein d'une constellation de satellites." Toulouse, ISAE, 2008. http://www.theses.fr/2008ESAE0006.
Full textAbstract:
L'objectif de ces travaux est d'utiliser des liaisons intersatellites (InterSatellite Links) au sein d'une constellation de satellites d'observation autonomes en termes de planification, permettant ainsi aux satellites de communiquer entre eux et d'avoir une indépendance maximale par rapport au sol. Nous considérons donc un problème d'affectation de tâches (1) dynamique car des tâches d'observation asynchrones sont générées au cours de l'exécution, (2) distribué car chaque satellite ne connaît qu'un sous-ensemble des tâches à réaliser et (3) contraint en communication car les satellites ne peuvent communiquer que lorsque leurs orbites se croisent. Nous proposons une approche décentralisée en modélisant la constellation de satellites par un système multiagent. Chaque agent planifie individuellement, communique avec ses voisins et coopère avec eux par la suite. Pour cela, nous proposons une notion de connaissance commune et de confiance en cette connaissance fondées sur le modèle d'accointances de la constellation ainsi qu'une méthode décentralisée de formation de coalitions par référence. Cette approche coopérative a été validée expérimentalement en proposant des métriques permettant de caractériser la dimension multiagent du système. Les résultats expérimentaux montrent que notre approche permet non seulement aux constellations de satellites de réaliser plus rapidement plus de tâches d'observation mais aussi de réduire la taille des constellations mises en œuvre pour un même niveau de performance.
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Sauter, Luke Michael 1979. "Satellite constellation design for mid-course ballistic missile intercept." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28888.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.Includes bibliographical references (p. 223-228).
This thesis will establish a conceptual approach to the design of constellations for satellite-based mid-course missile defense. The ballistic missile intercept problem leads to a new paradigm of coverage where interceptor "reachability" replaces line-of-sight coverage. Interceptors in this concept are limited in their time of flight and AV capabilities. Classical design approaches, based on ground coverage, are employed to provide a priori constellations for ballistic missile defense from a postulated North Korean attack. Both symmetric and asymmetric constellation types, designed for Earth coverage, provide bounds on the number of satellites required. A detailed parametric analysis is used to explore the constellation design space. Various constellation types are optimized to maximize missile defense coverage. Both genetic algorithms and gradient-based optimization techniques are employed. Satellite-based mid-course ballistic missile defense from a regional threat is achievable with as few as 21 satellites. Additional constellation intercept statistics, such as: the number of intercepts per missile, and interceptor closing velocities, are compiled to provide a lethality index. The effective capabilities of these constellations to defend CONUS, beyond the original regional threat, are also explored. It will be demonstrated that the constellations constructed in this work are capable of providing defense from an array of threatening states about the globe. This research illustrates how known design methods and astrodynamics techniques can be used to create new and viable methods of space-based missile defense.
by Luke Michael Sauter.
S.M.
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Smalarz, Bradley Ryan. "CubeSat Constellation Analysis for Data Relaying." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/650.
Full textAbstract:
Current CubeSat communication technology limits the amount of time, and number of accesses with ground stations. It has been proposed to use a constellation of CubeSats to improve relay performance and increase the number of accesses between a CubeSat and ground stations. By using the spatial and temporal analysis features of STK, coupled with the STK/Matlab interface a robust tool was created to analyze the performance of CubeSat constellations based on a store-and-forward communications model which is not currently supported by the STK Engine. Utilizing the Connect messaging format through a socket connection on the local machine, a Matlab graphical user interface, called SATCAT, was constructed in order to provide a user with the ability to control many aspects of the STK Engine externally. A function was created to use three Time Ordered Access (TOA) reports from STK to determine how long it would take for data to be relayed from a target to a ground station through a constellation of CubeSats. Three sample scenarios were created to demonstrate the use and performance analysis capabilities of SATCAT. The performance of a single CubeSat was analyzed and compared to the performance of a three CubeSat constellation and a thirty-seven CubeSat constellation. It was shown that a constellation of three CubeSats decreased the average relay time from 328 minutes to 149 minutes and a constellation of thirty-seven CubeSats further reduced the average relay time to only 3 minutes. While decreasing the average relay time, the constellation of three CubeSats also increased the number of accesses over a twenty-four hour period from 6 to 36, and the constellation of thirty-seven CubeSats allowed for 564 accesses.
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Hui, Liu, and Zhang Qishan. "ANALYSIS ON THE COVERAGE CHARACTERISTICS OF GLONASS CONSTELLATION." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/606822.
Full textAbstract:
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaThe coverage characteristics of the GLONASS constellation is analyzed. The almanac data of GLONASS navigation message are used in the computation according to the operation of the satellites. The ground traces of the GLONASS satellites are plotted. And the probability of visible satellite number is calculated under different latitude conditions. The results are analyzed to give descriptions of the GLONASS constellation. And they are compared with those of GPS's. The conclusion is verified that GLONASS constellation provides better coverage at high latitude.
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DiDomenico, Paul B. "A phase-based approach to satellite constellation analysis and design." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/42496.
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Asvial, Muhamad. "Satellite constellation design and radio resource management using genetic algorithm." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/842976/.
Full textAbstract:
A novel strategy for automatic satellite constellation design with satellite diversity is proposed. The automatic satellite constellation design means some parameters of satellite constellation design can be determined simultaneously. The total number of satellites, the altitude of satellite, the angle between planes, the angle shift between satellites and the inclination angle are considered for automatic satellite constellation design. Satellite constellation design is modelled using a multiobjective genetic algorithm. This method is applied to LEO, MEO and hybrid constellations. The advantage of this algorithm is automatic satellite constellation design whilst achieving dual satellite diversity statistics. Furthermore a new strategy of dynamic channel allocation is proposed using a genetic algorithm for use in MSS networks. The main idea behind this algorithm is to use minimum cost as a metric to provide optimum channel solutions for specified interference constraints. The frequency reuse condition for all spotbeams is investigated as a function of time. The update interval time and the sampling time are introduced in order to track time valiant coefficients and constraints of the algorithm. The method is demonstrated for S-UMTS based on a MEO satellite constellation. Using this algorithm, it is shown that the proposed model outperforms conventional DCA schemes in terms of capacity of the system and Quality of Service (QoS).We show in the thesis that the genetic algorithm is a robust method for calculation of dynamic variations in satellite constellation design and provides resource allocation improvements over DCA in MSS system networks.
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Kantsiper, Brian L. (Brian Lee). "A systematic approach to station-keeping of constellations of satellites." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50322.
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