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Dissertations / Theses on the topic 'Satellite Scheduling'
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1
Sauer, Birgit M. (Birgit Maria) 1971. "Autonomous mission scheduling for satellite operations." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/49978.
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Glim, Carl. "MULTI-USER SATELLITE TRACKING NETWORK SCHEDULING." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/609211.
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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaThe recent proliferation of Low Earth Orbiting (LEO) science, earth resources, and global communication satellites requires a significant number of ground stations for support. A network of satellite tracking ground stations with the ability to support multiple users and communicate with multiple satellites requires a robust scheduling and conflict resolution system. This paper describes an automated scheduling implementation for managing such a commercial, multi-user, multiple satellite, ground station network.
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Ganti, Anand 1975. "Transmission scheduling for wireless and satellite systems." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29316.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (p. 135-137).
We study queuing systems with time-varying service rates, as a natural model of satellite and wireless communication systems. Packets arrive at a satellite to be transmitted to one of the sub-regions (channels) in a service area. The packets are stored in an on-board buffer and in a separate queue for each channel. The satellite has a limited power available for scheduling transmissions, and a fixed number of transmitters. The power allocated to a particular channel, in conjunction with the channel state, determines the transmission rate of the channel, i.e., the service rate for the queue corresponding to that channel. The assignment of transmitters to the queues as well as the power allocated to each transmitter are modeled as control variables. The goal is to design a power allocation policy so that the expected queue size, in steady-state, is minimized. We model the system as a slotted system with N queues, and i.i.d. Bernoulli arrivals at each queue during each slot. Each queue is associated with a channel that changes between "on" and "off" states according to i.i.d. Bernoulli processes. We assume that the system has K identical transmitters ("servers").
(cont.) Each server, during each slot, can transmit up to Co packets from a queue associated with an "on" channel. We show that when K and Co are arbitrary and a total of up to KCo packets can be served from all the N queues in a time slot, a policy that assigns the K servers to the "on" channels associated with the K longest queues is optimal. We also consider a "fluid" service model under which fractional packets can be served, for the case K = N, and subject to a constraint that at most C packets can be served in total over all of the N queues. We show that there is an optimal policy which serves the queues so that the resulting vector of queue lengths is "Most Balanced." We also describe techniques to upper bound the expected queue size in steady-state under an optimal policy.
by Anand Ganti.
Ph.D.
4
Shen, Haijun. "Optimal scheduling for satellite refueling in circular orbits." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/12331.
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Kinney, Mark D. "General loss function applied to satellite scheduling optimization." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/43938.
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Approved for public release; distribution is unlimitedSatellite imagery utilization is an oversubscribed problem and therefore requires optimum scheduling methodology to maximize the use of the systems. There are many methods to determine performance of a scheduling algorithm, many of which rely on comparison to already established standards. Based on Taguchi’s quality loss function formulation that was developed for the manufacturing industry, four general quality loss functions are presented. These loss functions show the dollars lost when two different performances are changed. The two examined are (1) system response time to user image request and (2) total number of image requests satisfied. The general loss function is applied to the satellite scheduling problem to associate losses captured by the algorithm into a common unit, dollars lost. These loss functions, once developed, help decision makers determine how best to utilize their systems in terms of expected bottom line value to the company.
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Maillard, Adrien. "Flexible Scheduling for Agile Earth Observing Satellites." Thesis, Toulouse, ISAE, 2015. http://www.theses.fr/2015ESAE0024/document.
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Les satellites d’observation de la Terre sont des senseurs qui acquièrent des données, les compressent et les mémorisent à bord, puis les vident vers le sol. Des incertitudes rendent la planification des activités au sol de plus en plus discutable car la planification est alors pessimiste et les plans largement sous-optimaux. Cette thèse détaille la conception d'une planification mixte qui permet de profiter de la réalisation des paramètres incertains à bord tout en préservant la prévisibilité de l'exécution pour les opérateurs au sol. Notre première contribution concerne le problème de planification des vidages. Un mécanisme de planification flexible a été conçu dans lequel seules les acquisitions de haute priorité sont planifiées de manière pessimiste. A bord, un algorithme adapte le plan en fonction des volumes réels, en s'assurant que le vidage des acquisitions de haute priorité est toujours garanti, et insère des nouveaux vidages si possible. Notre deuxième contribution concerne le problème de planification des acquisitions. Au sol, des contraintes contribuent à éliminer du plan de nombreuses acquisitions qui auraient pu être réalisées car les niveaux de ressources à bord sont souvent plus hauts que ceux prévus par ces contraintes. Dans un nouveau mécanisme de décision, le sol produit des plans conditionnels dans lesquels la réalisation des acquisitions de basse priorité est conditionnée par des niveaux d'énergie requis. Comparées à d'autres mécanismes de planification, ces deux approches flexibles permettent d'éviter le gaspillage des ressources et de réaliser plus d'acquisitions et de vidages tout en conservant de la prévisibilitéEarth-observation satellites are space sensors which acquire data, compress and record it on board, and then download it to the ground. Some uncertainties make planning and scheduling satellite activities offline on the ground more and more arguable as worst-case assumptions are made about uncertain parameters and plans are suboptimal. This dissertation details our efforts at designing a flexible decision-making scheme that allows to profit from the realization of uncertain parameters on board while keeping a fair level of predictability on the ground. Our first contribution concerns the data download problem. A flexible decision-making mechanism has been designed where only high-priority acquisition downloads are scheduled with worst-case assumptions. Other acquisition downloads are scheduled with expected parameters and conditioned by resource availability. The plan is then adapted on board. Our second contribution concerns the acquisition planning problem. A lot of acquisitions that could have been done are eliminated when planning because of worst-case assumptions. In a new decision-making scheme, these high-level constraints are removed for low-priority acquisitions. Observation plans produced on the ground are conditional plans involving conditions for triggering low-priority acquisitions. Compared with pure ground and pure onboard methods, these two approaches avoid wastage of resource and allow more acquisitions to be executed and downloaded to the ground while keeping a fair level of predictability on the ground
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Horan, Stephen. "An Operational Concept for a Demand Assignment Multiple Access System for the Space Network." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611436.
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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaAn operational concept for how a Demand Access Multiple Assignment (DAMA) system could be configured for the NASA Space network is examined. Unique aspects of this concept definition are the use of the Multiple Access system within the Space Network to define an order wire channel that continuously scans the Low Earth Orbit space for potential users and the use of advanced digital signal processing technology to look for the Doppler-shifted carrier signal from the requesting satellite. After the reception of the signal, validation and processing of the request is completed. This paper outlines the concept and the ways in which the system could work.
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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
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Xu, Kai J. "Radio Resource Management for Satellite UMTS. Dynamic scheduling algorithm for a UMTS-compatible satellite network." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/5685.
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The third generation of mobile communication systems introduce
interactive Multicast and Unicast multimedia services at a fast data rate of
up to 2 Mbps and is expected to complete the globalization of the mobile
telecommunication systems. The implementation of these services on
satellite systems, particularly for broadcast and multicast applications to
complement terrestrial services is ideal since satellite systems are capable
of providing global coverage in areas not served by terrestrial
telecommunication services. However, the main bottleneck of such
systems is the scarcity of radio resources for supporting multimedia
applications which has resulted in the rapid growth in research efforts for
deriving efficient radio resource management techniques. This issue is
addressed in this thesis, where the main emphasis is to design a dynamic
scheduling framework and algorithm that can improve the overall
performance of the radio resource management strategy of a UMTS
compatible satellite network, taking into account the unique characteristics
of wireless channel conditions.
This thesis will initially be focused on the design of the network and
functional architecture of a UMTS -compatible satellite network. Based on
this architecture, an effective scheduling framework is designed, which
can provide different types of resource assigning strategies. A functional
model of scheduler is defined to describe the behaviours and interactions
between different functional entities.
An OPNET simulation model with a complete network protocol stack is
developed to validate the performance of the scheduling algorithms
implemented in the satellite network. Different types of traffic are
considered for the OPNET simulation, such as the Poisson Process, ONOFF
Source and Self Similar Process, so that the performance of
scheduling algorithm can be analyzed for different types of services.
A novel scheduling algorithm is proposed to optimise the channel
utilisation by considering the characteristics of the wireless channel, which
are bursty and location dependent. In order to overcome the channel
errors, different code rates are applied for the user under different channel
conditions. The proposed scheduling algorithm is designed to give higher
priority to users with higher code rate, so that the throughput of network is
optimized and at the same time, maintaining the end users¿ service level
agreements. The fairness of the proposed scheduling algorithm is
validated using OPNET simulation. The simulation results show that the
algorithm can fairly allocate resource to different connections not only
among different service classes but also within the same service class
depending on their QoS attributes.Inmarsat Global Ltd. BGAN and the European Space Agency (ESA)
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Xu, Kai. "Radio resource management for satellite UMTS : dynamic scheduling algorithm for a UMTS-compatible satellite network." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/5685.
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The third generation of mobile communication systems introduce interactive Multicast and Unicast multimedia services at a fast data rate of up to 2 Mbps and is expected to complete the globalization of the mobile telecommunication systems. The implementation of these services on satellite systems, particularly for broadcast and multicast applications to complement terrestrial services is ideal since satellite systems are capable of providing global coverage in areas not served by terrestrial telecommunication services. However, the main bottleneck of such systems is the scarcity of radio resources for supporting multimedia applications which has resulted in the rapid growth in research efforts for deriving efficient radio resource management techniques. This issue is addressed in this thesis, where the main emphasis is to design a dynamic scheduling framework and algorithm that can improve the overall performance of the radio resource management strategy of a UMTS compatible satellite network, taking into account the unique characteristics of wireless channel conditions. This thesis will initially be focused on the design of the network and functional architecture of a UMTS -compatible satellite network. Based on this architecture, an effective scheduling framework is designed, which can provide different types of resource assigning strategies. A functional model of scheduler is defined to describe the behaviours and interactions between different functional entities. An OPNET simulation model with a complete network protocol stack is developed to validate the performance of the scheduling algorithms implemented in the satellite network. Different types of traffic are considered for the OPNET simulation, such as the Poisson Process, ONOFF Source and Self Similar Process, so that the performance of scheduling algorithm can be analyzed for different types of services. A novel scheduling algorithm is proposed to optimise the channel utilisation by considering the characteristics of the wireless channel, which are bursty and location dependent. In order to overcome the channel errors, different code rates are applied for the user under different channel conditions. The proposed scheduling algorithm is designed to give higher priority to users with higher code rate, so that the throughput of network is optimized and at the same time, maintaining the end users' service level agreements. The fairness of the proposed scheduling algorithm is validated using OPNET simulation. The simulation results show that the algorithm can fairly allocate resource to different connections not only among different service classes but also within the same service class depending on their QoS attributes.
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Gilmore, John Sebastian. "Development of a satellite communications software system and scheduling strategy." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4152.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Stellenbosch University and the Katholieke Universiteit Leuven has a joint undertaking to develop a satellite communications payload. The goals of the project are: to undertake research and expand knowledge in the area of dynamically configurable antenna beam forming, to prove the viability of this research for space purposes and to demonstrate the feasibility of the development in a practical application. The practical application is low Earth orbit satellite communication system for applications in remote monitoring. Sensor data will be uploaded to the satellite, stored and forwarded to a central processing ground station as the satellite passes over these ground stations. The system will utilise many low-cost ground sensor stations to collect data and distribute it to high-end ground stations for processing. Applications of remote monitoring systems are maritime- and climate change monitoring- and tracking. Climate change monitoring allows inter alia, for the monitoring of the effects and causes of global warming. The Katholieke Universiteit Leuven is developing a steerable antenna to be mounted on the satellite. Stellenbosch University is developing the communications payload to steer and use the antenna. The development of the communications protocol stack is part of the project. The focus of this work is to implement the application layer protocol, which handles all file level communications and also implements the communications strategy. The application layer protocol is called the Satellite Communications Software System (SCSS). It handles all high level requests from ground stations, including requests to store data, download data, download log files and upload configuration information. The design is based on a client-server model, with a Station Server and Station Handler. The Station Server schedules ground stations for communication and creates a Station Handler for each ground station to handle all ground station requests. During the design, all file formats were defined for efficient ground station-satellite communications and system administration. All valid ground station requests and handler responses were also defined. It was also found that the system may be made more efficient by scheduling ground stations for communications, rather than polling each ground station until one responds. To be able to schedule ground station communications, the times when ground stations will come into view of the satellite have to be predicted. This is done by calculating the positions of the Satellite and ground stations as functions of time. A simple orbit propagator was developed to predict the satellite distance and to ease testing and integration with the communications system. The times when a ground station will be within range of the satellite were then predicted and a scheduling algorithm developed to minimise the number of ground stations not able to communicate. All systems were implemented and tested. The SCSS executing on the Satellite was developed and tested on the satellite on-board computer. Embedded implementations possess strict resource limitations, which were taken into account during the development process. The SCSS is a multi-threaded system that makes use of thread cancellation to improve responsiveness.
AFRIKAANSE OPSOMMING: Die Universiteit van Stellenbosch ontwerp tans ’n satelliet kommunikasieloonvrag in samewerking met die Katolieke Universiteit van Leuven. Die doel van die projek is om navorsing te doen oor die lewensvatbaarheid van dinamies verstelbare antenna bundelvorming vir ruimte toepassings, asook om die haalbaarheid van hierdie navorsing in die praktyk te demonstreer. Die praktiese toepassing is ’n satellietkommunikasiestelsel vir afstandsmonitering, wat in ’n Lae-Aarde wentelbaan verkeer. Soos die satelliet in sy wentelbaan beweeg, sal sensor data na die satelliet toe gestuur, gestoor en weer aangestuur word. Die stelsel gebruik goedkoop sensorgrondstasies om data te versamel en aan te stuur na kragtiger grondstasies vir verwerking. Afstandsmoniteringstelsels kan gebruik word om klimaatsverandering, sowel as die posisie van skepe en voertuie, te monitor. Deur oa. klimaatsveranderinge te dokumenteer, kan gevolge en oorsake van globale verhitting gemonitor word. Die Katholieke Universiteit van Leuven is verantwoordelik vir die ontwerp en vervaardiging van die satelliet antenna, terwyl die Universiteit van Stellenbosch verantwoordelik is vir die ontwerp en bou van die kommunikasie loonvrag. ’n Gedeelte van hierdie ontwikkeling sluit die ontwerp en implementasie van al die protokolle van die kommunikasieprotokolstapel in. Dit fokus op die toepassingsvlak protokol van die protokolstapel, wat alle leêrvlak kommunikasie hanteer en die kommunikasiestrategie implementeer. Die toepassingsvlaksagteware word die Satellietkommunikasie sagtewarestelsel (SKSS) genoem. Die SKSS is daarvoor verantwoordelik om alle navrae vanaf grondstasies te hanteer. Hierdie navrae sluit die oplaai en stoor van data, die aflaai van data, die aflaai van logs en die oplaai van konfigurasie inligting in. Die ontwerp is op die standaard kliënt-bediener model gebasseer, met ’n stasiebediener en ’n stasiehanteerder. Die stasiebediener skeduleer die tye wanneer grondstasies toegelaat sal word om te kommunikeer en skep stasiehanteerders om alle navrae vanaf die stasies te hanteer. Gedurende die ontwerp is alle leêrformate gedefinieer om doeltreffende adminstrasie van die stelsel, asook kommunikasie tussen grondstasies en die satelliet te ondersteun. Alle geldige boodskappe tussen die satelliet en grondstasies is ook gedefnieer. Daar is gevind dat die doeltreffendheid van die stelsel verhoog kan word deur die grondstasies wat wil kommunikeer te skeduleer, eerder as om alle stasies te pols totdat een reageer. Om so ’n skedule op te stel, moet die tye wanneer grondstasies binne bereik van die satelliet gaan wees voorspel word. Hierdie voorspelling is gedoen deur die posisies van die satelliet en die grondstasies as funksies van tyd te voorspel. ’n Eenvoudige satelliet posisievoorspeller is ontwikkel om toetsing en integrasie met die SKSS te vergemaklik. ’n Skeduleringsalgoritme is toe ontwikkel om die hoeveelheid grondstasies wat nie toegelaat word om te kommunikeer nie, te minimeer. Alle stelsels is geimplementeer en getoets. Die SKSS, wat op die satelliet loop, is ontwikkel en getoets op die satelliet se aanboord rekenaar. Die feit dat ingebedde stelsels oor baie min hulpbronne beskik, is in aanmerking geneem gedurende die ontwikkeling en implementasie van die SKSS. Angesien die SKSS ’n multidraadverwerkingsstelsel is, word daar van draadkansellasie gebruik gemaak om die stelsel se reaksietyd te verbeter.
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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.
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Czerniak, Paul T. (Paul Thaddeus) 1976. "Approximation techniques for the optimal scheduling of the Space-Based Visible satellite." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86797.
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Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 61).
by Paul T. Czerniak.
M.Eng.and S.B.
14
Mata, Fernando. "Properties of the satellite location polyhedron and its relation to the scheduling polyhedron /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487685204969045.
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Anderson, Mike, Peter Militch, and Hugh Pickens. "AN AUTONOMOUS SATELLITE TRACKING STATION." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/607307.
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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaIn 1998, AlliedSignal Technical Services (ATSC) installed three fully autonomous 13-meter satellite tracking systems for the Integrated Program Office of the National Oceanic and Atmospheric Administration (NOAA) at the Command and Data Acquisition Station near Fairbanks, Alaska. These systems track and command NOAA Polar Orbiting Weather Satellites and Defense Meteorological Satellites. Each tracking system operates for extended periods of time with little intervention other than periodic scheduling contacts. Schedule execution initiates equipment configuration, including establishing the RF communications link to the satellite. Station autonomy is achieved through use of a robust scheduler that permits remote users and the System Administrator to request pass activities for any of the supported missions. Spacecraft in the mission set are scheduled for normal operations according to the priority they have been assigned. Once the scheduler resolves conflicts, it builds a human-readable control script that executes all required support activities. Pass adds or deletes generate new schedule scripts and can be performed in seconds. The systems can be configured to support CCSDS and TDM telemetry processing, but the units installed at Fairbanks required only telemetry and command through-put capabilities. Received telemetry data is buffered on disk-storage for immediate, post-pass playback, and also on tape for long-term archiving purposes. The system can autonomously support up to 20 spacecraft with 5 different configuration setups each. L-Band, S-Band and X-Band frequencies are supported.
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Hemberg, Alexander. "Automated booking and scheduling for CubeSats : Development of an automated Scheduling engine for satellite communication with emphasis on communication with CubeSats." Thesis, KTH, Rymd- och plasmafysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160615.
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This thesis work details the development of an automatic scheduling engine for satellite communication from the operational stand point of a ground station. The aim has been to create a scheduling engine that autonomously calculates passes for a large number of satellites over a ground station and assigns these passes to appropriate resources. The process used can be described as rule based scheduling, where each satellite is assigned a set of specic requirements that the scheduler tries to satisfy in order to create a schedule that satises all specied requirements. This approach is in contrast to the most commonly used scheduling today, where satellite operators request passes and ground stations try to satisfy these requests, often manually. With rule based scheduling satellite operators are instead allowed to set requirements and the pass times are chosen automatically so as to optimize the process and admit a higher utilization of available resources. It is shown that a typical utilization of a ground stations resources of about 60% can be achieved. In addition to the scheduling engine a simple web interface has been developed, allowing the control of all parameters and scheduling through a web browser, thus demonstrating the ability to make this system more widely accessible for a broader range of users. The development of a rule based scheduler illustrates the possibility of making the process of satellite to ground communications more streamlined from the part of the ground station while at the same time permitting an increase in the number of passes it can support.Det har examensarbetet beskriver utvecklingen av en autonom schemalaggare for satellitkommunikation fran en markstations perspektiv. Syftet har varit att skapa en autonom schemalaggare som pa egen hand beraknar passtider for ett stort antal satelliter over en markstation och schemalagger dessa pass pa lampliga resurser. Processen som anvands kan beskrivas som regelbaserad schemalaggning, dar varje satellit som ska schemalaggas tilldelas ett antal specika krav som schemalaggaren sedan forsoker tillfredsstalla for att pa sa satt skapa ett schema som tillfredsstaller alla krav fran alla satellitoperatorer. Det har angreppssattet skiljer sig fran det som anvands mest idag, dar satellitoperatorer staller detaljerade krav pa vilka pass som ska bokas in hos markstationen, och personalen pa markstationen forsoker att tillfredsstalla dessa krav sa langt det ar mojligt, ibland manuellt. Med regelbaserad schemalaggning far satellitoperatorer istallet specicera ett set med krav for sina satelliter, och schemalaggaren valjer passtider sa att alla krav for alla satelliter tillgodoses pa ett sa eektivt satt som mojligt, sa att en hogre belaggning pa markstationen kan uppnas an vad som annars vore mojligt. Det visas i dokumentet att en belaggning pa ca 60 % ar mojlig med hjalp av regelbaserad schemalaggning; hogre an normalscenariot for en markstation idag. Utover schemalaggaren har ett webbaserat granssnitt utvecklats som mojliggor kontroll av satellitparametrar och schemalaggning via en webblasare. Pa sa satt visas mojligheten att gora ett sadant har system tillgangligt for ett brett spektrum av anvandare. Utvecklingen av en automatiserad schemalaggare illustrerar mojligheten att forenkla processen for passbokning av satellit till markstationskommunikation samtidigt som en forhallandevis hog belaggning kan uppnas.
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Sunshine, Carl, and Lance Williams. "ACHIEVING DATA TRANSFER AND SERVICE MANAGEMENT INTEROPERABILITY IN SATELLITE CONTROL NETWORKS." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605583.
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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, NevadaA critical area for achieving interoperability between satellite control networks is the means chosen to interconnect Satellite Operations Centers and remote antenna systems. The CCSDS Space Link Extension (SLE) services are good candidates for this purpose, but national security space activities have demanding requirements for accuracy of data transfer, controlled delay, and security, which may not be fully achievable with the existing recommendations. The US Air Force developed a test bed to evaluate the SLE protocols during live satellite contacts, for both data transfer and management functions such as scheduling, configuring ground resources, and status reporting. Performance was generally satisfactory, but several extensions were found to be necessary. The SLE services provide a promising basis for use in ground stations to support both legacy Air Force interfaces and newer standards based satellite control services.
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Capitanu, Calin. "Fault Detection, Isolation and Recovery : Analysis of two scheduling algorithms." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300128.
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Unmanned, as well as manned space missions have seen a high failure rate in the early era of space technology. However, this decreased a lot since technology advanced and engineers learnt from previous experiences and improved critical real time systems with fault detection mechanisms. Fault detection, isolation and recovery, nowadays, is generally available in every flying device. However, the cost of hardware can bottleneck the process of creating such a system that is both robust and responsive. This thesis analyses the possibility of implementing a fault detection, isolation and recovery system inside of a single-threaded, cooperative scheduling operating system. The thesis suggests a cooperative implementation of such a system, where every task is responsible for parts of the fault detection. The analysis is done from both the integration layer, across the operating system and its tasks, as well as from the inside of the detection system, where two key components are implemented and analyzed: debug telemetry and operation modes. Results show that it is possible to implement a fault detection system that is spread across all the components of the satellite and acts cooperatively. Furthermore, the comparison with a traditional, dedicated fault detection system proves that errors can be caught faster with a cooperative mechanism.Obemannade såväl som bemannade rymduppdrag har sett ett högt misslyckande i rymdteknikens tidiga era. Detta har dock förbättrats mycket sedan ingenjörer började lära sig av sina tidigare erfarenheter och utrustade kritiska realtidssystem med feldetekteringsmekanismer. Idag är alla flygande enheter utrustade med feldetekterings-, isolerings- och återställningsmekanismer. Däremot kan kostnaden för hårdvara vara ett problem för processen att skapa ett sådant system som är både robust och mottagligt. Denna uppsats analyserar möjligheten att implementera ett feldetekterings-, isolerings- och återställningssystem inuti ett enkelgängat samarbetsplaneringssystem. Denna uppsats föreslår ett samarbete för implementering av ett sådant system, där varje uppgift ansvarar för delar av feldetekteringen. Analysen görs från både integrationsskiktet, över operativsystemet och dess uppgifter, samt från insidan av detekteringssystemet, där två nyckelkomponenter implementeras och analyseras. Resultaten visar att det är möjligt att implementera ett feldetekteringssystem som täcker alla satellitkomponenter och som är mottaglig. Dessutom visar jämförelsen med ett traditionellt, dedikerat feldetekteringssystem att fel kan fångas snabbare med en mottagligmekanism.
Misiunile spat,iale cu oameni, atât cât s, i fara oameni, au avut o rata a es, ecurilor destul de ridicata în perioada init,iala a erei tehnologiei spat,iale. În schimb, aceasta a scazut semnificativ odata cu dezvoltarea tehnologiei, dar s, i datorita faptului ca inginerii au învat,at din experient,ele precendente s, i au îmbunatat, it sistemele critice în timp real cu mecanisme de detect,ie a erorilor. Sisteme de detect,ie, izolare s, i recuperare din erori sunt disponibile astazi în aproape toate sistemele spat,iale. Însa, costul echipamentelor poate împiedica crearea unor astfel de sisteme de detect,ie, care sa fie robuste s, i responsive. Aceasta teza analizeaza posibilitatea implementarii unui sistem de detect,ie, izolare s, i recuperare de la erori într-un satelit care este echipat cu un procesor cu un singur fir de execut,ie, care are un sistem de planificare cooperativ în sistemul de operare. Aceasta teza sugereaza o implementare cooperativa a unui astfel de sistem, unde fiecare proces este responsabil de câte o parte din detectarea erorilor. Analiza este realizata atât din perspectiva integrarii în sistemul de operare s, i procesele acestuia, cât s, i din interiorul acestui sistem de detect,ie, unde doua elemente importante sunt implementate s, i analizate: telemetria de depanare s, i modurile de operare. Rezultatele arata faptul ca este posibila implementarea unui sistem de detect,ie care este împart, it în toate componentele sistemului unui satelit s, i se comporta cooperativ. Mai departe, comparat,ia cu un sistem tradit,ional, dedicat, de detect,ie a erorilor arata ca erorile pot fi detectate mai rapid cu un sistem cooperativ.
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Niculae, Alexandra Mihaela. "Mécanismes d'optimisation multi-niveaux pour IP sur satellites de nouvelle génération." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT034H/document.
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L'objectif de cette thèse est de fournir aux réseaux satellitaires géostationnaires des outils d'amélioration de performances dans un contexte contraint, lié au support de communication qui présente une qualité variable. Les défis s'étendent de la couche d'accès au support (l'ordonnancement) à la couche transport (le comportement du TCP étant sensible au délai de propagation dans les réseaux géostationnaires). Nous faisons appel aux mécanismes cross-layer qui mettent en place des interactions entre entités protocolaires non adjacentes du modèle OSI offrant ainsi une adaptation immédiate au changement des conditions dans le réseau. Nous employons à ce but une technique cross-layer informant l'entité protocolaire TCP du débit disponible, permettant d'éviter des conséquences telles que la chute du débit et des pertes liées à la congestion des files d'attente. Nous mettons en oeuvre ce mécanisme au niveau d'un élément sensible du réseau géostationnaire, le proxy TCP. L'intérêt des techniques cross-layer a été mis en évidence au niveau de l'ordonnanceur présent au sein de la gateway d'un réseau DVB-S2/DVB-RCS. Ainsi, ils contribuent à la maximisation de la capacité du système, à l'assurance des contraintes de qualité de service, à l'équité de l'allocation de ressources, etc. Enfin, nous présentons une solution possible d'architecture cross-layer. Nous proposons des caractéristiques demandées pour une architecture cross-layer afin d'assurer l'évolutivité, la modularité et la co-existence avec l'architecture standard existanteThe main objective of this thesis is to provide tools of improving performance of geostationary satellite networks, operating in a constrained environment mainly due to the variable quality of radio links. There are protocol layers being challenged by such characteristics, such as the medium access protocol and the transport layer protocol (TCP behaviour is impacted by the long propagation delay in geostationary satellite networks). We employ cross-layer mechanisms implementing interaction between non-adjacent protocol layers defined by the OSI architecture aiming at providing a rapid adaptation to changes in network state. We provide a cross-layer technique informing TCP protocol of the available network rate, thus preventing consequences such as TCP rate drop or loss due to buffer overflow. This mechanism is to be implemented in a sensible network element, such as a TCP proxy. Data link layer scheduler can benefit from the advantages of employing cross-layer mechanisms, especially at the gateway of a DVB-S2/DVB-RCS satellite network. The improved scheduler allows an efficient use of network resources and helps insuring quality of services constraints, resource allocation fairness, etc. Finally, we propose a cross-layer architecture along with in-demand characteristics able to offer an inter-operability with the existing architecture, an easy up-grade and design
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Belli, Jacob. "Mission Analysis for Pico-Scale Satellite Based Dust Detection in Low Earth Orbits." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5764.
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A conceptual dust detection mission, KnightSat III, using pico-scale satellites is analyzed. The purpose of the proposed KnightSat III mission is to aid in the determination of the size, mass, distribution, and number of dust particles in low earth orbits through a low cost and flexible satellite or a formation of satellites equipped with a new dust detector. The analysis of a single satellite mission with an on-board dust detector is described; though this analysis can easily be extended to a formation of pico-scale satellites. Many design aspects of the mission are discussed, including orbit analysis, power management, attitude determination and control, and mass and power budgets. Two of them are emphasized. The first is a new attitude guidance and control method, and the second is the online optimal power scheduling. It is expected that the measurements obtained from this possible future mission will provide insight into the dynamical processes of inner solar system dust, as well as aid in designing proper micro-meteoroid impact mitigation strategies for future man-made spacecraft.M.S.A.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Aerospace Engineering; Space System Design and Engineering
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Dupe, Jean-Baptiste. "Ordonnancement et gestion des ressources pour un système de télécommunications haut débit : Optimisation de la bande passante satellite." Thesis, Toulouse, INPT, 2015. http://www.theses.fr/2015INPT0136/document.
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Les télécommunications par satellite ont connu ces dernières années un regain d'intérêt important, du fait de leur capacité à permettre la réduction de la fracture numérique. En effet, un satellite en orbite géostationnaire peut s'appuyer sur une très grande couverture et une capacité importante pour atteindre des zones où le déploiement des réseaux terrestres n'est pas envisageable, comme les transports (bateau, avion), ou bien les zones blanches, où il serait difficilement rentable. Traditionnellement concentrés sur la diffusion de télévision numérique, les dernières générations de standards reflètent cet engouement en faisant une place de choix à la transmission de données bidirectionnelle, notamment en permettant une prise en charge simple des protocoles de l'Internet. Le problème de l'ordonnancement dans ces systèmes devient alors particulièrement important, puisqu'il doit prendre en compte deux processus évoluant de manière totalement décorrélée. D'un côté, l'évolution de la demande des utilisateurs, dépendante des applications (vidéo, voix, données). De l'autre, l'évolution de la capacité du système, celle-ci étant tributaire des conditions de transmission : les fréquences utilisées dans ces systèmes sont particulièrement sensibles à l'atténuation due à l'eau dans l'atmosphère. Cette thèse s'intéresse au problème de l'ordonnancement et de l'allocation de ressources, dans le but de fournir un service comparable aux réseaux terrestres en termes de services, en présentant les meilleures performances possibles. Si un certain nombre de propositions ont été faites sur le sujet, aucune ne prend en compte l'ensemble des contraintes d'un tel système. Outre le caractère variable de la capacité, la variabilité de la demande, conjuguée avec les contraintes de qualité de service constitue une difficulté supplémentaire. Enfin, il nous faut considérer la faisabilité de notre solution dans un contexte temps réel, nécessaire dans l'optique d'une implantation dans un système réel. Nous avons ainsi développé une architecture d'ordonnanceur pour la voie Aller, reposant sur des fonctions d'utilité, permettant ainsi une formulation simple du compromis entre demande et capacité. Nous montrons comment cet algorithme pourrait être utilisable dans un système complet, à travers une implantation détaillée, de faible complexité, ainsi que des simulations de cas réels. Nous portons ensuite notre attention sur la voie Retour, où nous proposons une méthode d'allocation de ressources prenant en compte de manière conjointe la qualité de service et la qualité du support pour délivrer une allocation à la fois conforme et performante. Les simulations montrent que notre algorithme obtient une efficacité et une meilleure gestion du trafic que des solutions de référence présentées dans la littératureSatellite telecommunications have seen a tremendous increase in interest, due to its ability to reduce the digital divide. In fact, a geostationary satellite can take advantage of its very wide coverage and high capacity to reach areas where deployment of a terrestrial network would not be possible, such as transports, or too expensive to be profitable, as in remote areas. Traditionally focused on digital television broadcasting, the latest generation of standards have evolved to reflect those new needs, dealing extensively with the transmission of interactive data, particularly by natively supporting Internet protocols. Scheduling has arisen as a major issue of those modern systems, since it has to deal with to highly uncorrelated processes: demand and capacity. Demand, on one side, evolves with user's needs, and therefore with the applications they are using: video, voice or data. Capacity, on the other side, depends on meteorological conditions over the satellite's cover, as the frequencies used in such systems are very sensitive to wet atmosphere attenuation. This thesis aims to study the problem of scheduling and resource allocation, hoping to achieve a service that can match with terrestrial networks in terms of services, while showing the best possible performances. If numerous solutions were proposed on this topic, none is taking into account all of the current system's constraints. In addition to the variable nature of system's capacity, the conjunction of variable demand and quality of service constraints constitutes an additional issue. Furthermore, we have to consider the practicability of our solution in a real-time context, necessary if we aim for industrial use. We have first developed a scheduler architecture for the Forward link, based on utility functions, thus allowing a simple formulation of the capacity versus demand compromise. We show, through a detailed low-complexity implementation and accurate simulations, how our algorithm could be used efficiently in an industrial context. We then focus on the Return link, where we propose a resource allocation method, taking into account quality of service and quality of transmission jointly to deliver an efficient yet consistent resource allocation. Simulations show that our algorithm achieves a better efficiency and traffic handling than reference solutions presented in the literature
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Choi, Jihwan Patrick 1975. "Resource allocation and scheduling for communication satellites with advanced transmission antennas." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38298.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 175-180).
For multimedia and other data services over satellite networks, the efficient management of scarce satellite communication resources is critical for the economic competitiveness of the medium. To support a broad spectrum of users with small terminals at high data rates, narrow transmit spotbeams from the satellite must be used. Since satellite on-board resources are too expensive to illuminate all of the spotbeam-coverage cells within the satellite service area, an optimized method of agile antenna gain patterning and beam scheduling is required to greatly improve the efficiency of transmission and power management. In this thesis, we jointly optimize resource allocation/scheduling, congestion control and antenna gain patterning for communication satellites with advanced transmission antennas. Then, we develop a low-complexity on-line algorithm that considers channel conditions, interference and average delay constraints, and approaches the theoretical steady-state limit. We introduce optimized beam profiling based on traffic demand and channel conditions over satellite downlinks, which can achieve a substantial power gain and reasonable proportional fairness. We show that a modest number of active parallel beams are sufficient to cover many cells efficiently with dynamic capacity allocation.
(cont.) Next, for the multiple beam antenna case, we develop a jointly optimized scheme of beam allocation and congestion control with transmitter-sharing and average delay constraints, which provides high throughput and/or small average queueing delays. Last, we find the solution for joint antenna gain patterning and scheduling by considering spatially close co-channel interference in the use of phased array antenna. We suggest an optimum scheduling policy, which selects users with higher marginal returns of a composite cost function with respect to allocated power, in terms of better channel conditions, less interference (depending on users' geographic distribution), and larger delay. The simulation result indicates that a real-time on-line algorithm can achieve a throughput close to the analytic steady-state upper bound. Due to its flexible power allocation, we demonstrate that the phased array antenna can provide better performance than the multiple beam antenna when a small number of users are very demanding or many users are located in a small and crowded area
by Jihwan Patrick Choi.
Ph.D.
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Monmousseau, Philippe. "Scheduling of a Constellation of Satellites: Improving a Simulated Annealing Model by Creating a Mixed-Integer Linear Model." Thesis, KTH, Optimeringslära och systemteori, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-179300.
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The purpose of this thesis is to provide a new scheduling model of a large constellation of imaging satellites that does not use a heuristic solving method. The objective is to create a mixed-integer linear model that would be competitive in speed and in its closeness to reality against a current model using simulated annealing, while trying to improve both models. Each satellite has the choice between a number of possible events, each event having a utility and a cost, and the chosen schedule must take into account numerous time-related constraints. The main difficulties appeared in modeling realistically a battery level and in handling infeasible configurations due to inaccurate parameters. The obtained linear model has enabled a better understanding of the performance of the simulated annealing solver, and could also be adapted to different real-world scheduling problems.
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Aiyetoro, Gbolahan Rilwan. "Packet scheduling in satellite HSDPA networks." Thesis, 2010. http://hdl.handle.net/10413/3709.
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The continuous growth in wireless networks is not showing any sign of slowing down as new services, new technologies and new mobile users continue to emerge. Satellite networks are expected to complement the terrestrial network and be a valid option to provide broadband communications services to both fixed and mobile users in scenarios where terrestrial networks cannot be used due to technical and economical viability. In the current emerging satellite networks, where different users with varying traffic demands ranging from multimedia, voice to data and with limited capacity, Radio Resource Management (RRM) is considered as one of the most significant and challenging aspect needed to provide acceptable quality of service that will meet the requirements of the different mobile users. This dissertation considers Packet Scheduling in the Satellite High Speed Downlink Packet Access (S-HSDPA) network. The main focus of this dissertation is to propose a new cross-layer designed packet scheduling scheme, which is one of the functions of RRM, called Queue Aware Channel Based (QACB) Scheduler. The proposed scheduler, which, attempts to sustain the quality of service requirements of different traffic requests, improves the system performance compared to the existing schedulers. The performance analysis comparison of the throughput, delay and fairness is determined through simulations. These metrics have been chosen they are three major performance indices used in wireless communications. Due to long propagation delay in HSDPA via GEO satellite, there is misalignment between the instantaneous channel condition of the mobile user and the one reported to the base station (Node B) in S-HSDPA. This affects effectiveness of the channel based packet schedulers and leads to either under utilization of resource or loss of packets. Hence, this dissertation investigates the effect of the introduction of a Signal-to-Noise (SNR) Margin which is used to mitigate the effect of the long propagation delay on performance of S-HSDPA, and the appropriate SNR margin to be used to achieve the best performance is determined. This is determined using both a semi-analytical and a simulation approach. The results show that the SNR margin of 1.5 dB produces the best performance.
Finally, the dissertation investigates the effect of the different Radio Link Control (RLC) Transmission modes which are Acknowledged Mode (AM) and Unacknowledged Mode (UM) as it affects different traffic types and schedulers in S-HSDPA. Proportional fair (PF) scheduler and our proposed, QACB, scheduler have been considered as the schedulers for this investigation. The results show that traffic types are sensitive to the transmitting RLC modes and that the QACB scheduler provides better performance compared to PF scheduler in the two RLC modes considered.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.
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劉盈妤. "Satellite Imaging Scheduling by Clustering Method." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/27751503039772992058.
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碩士國立新竹教育大學
人資處數學教育碩士班
98
In this paper, we study the imaging scheduling of the single remote sensing satellite by using cluster analysis. The orbit of a satellite is setting around the Earth. We use cluster analysis and scheduling method to reduce the count, promote timeliness, and achieve the greatest of the approximate solution. This heuristic algorithm is more practical than the Exhaustive-Attack-method since it is brute and time-consuming. In this study, we assume that the satellite was enabled to remote sensing images, between different clusters, continually or one time breaking. We begin the next imaging before the satellite camera angle conversion and mobile satellite location. Especially, the imaging range and power have specific limits. After determining the imaging range, we apply two-step cluster analysis by using the hierarchical method by the Hierarchical procedure and the non-hierarchical method by K-Means Cluster procedure, alternatively; until the cluster group is a steady state. Then, the first and second highest clusters are selected for finding the best scheduling. The experimental simulation results show that the more clusters cause the higher number of the count tasks. But increases to a peak volume, it makes the number of tasks in a single cluster that are too few and the total sum of counting that is reduce. In general, when a larger number of sample tasks will make a higher number of the clusters.
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Wei-Cheng, Lin. "Satellite Imaging Scheduling: Algorithm Design and Application." 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2901200523124400.
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林湘淩. "An Algorithm of Scheduling for Satellite Imaging." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/69883186609002090064.
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碩士國立新竹教育大學
人資處數學教育碩士班
98
This thesis presents on scheduling of satellite imaging tasks solving. For satellite routing and imaging tasks have different resources combinations and limitations. The imaging scheduling problem is a complicated problem that needs to consider various kinds of parameters, which including the power and thermal constrain of satellite, changeover efforts between two consecutive imaging operations (tasks). The goal of satellite imaging scheduling is based on these limitations to find the maximum image tasks as we can do. As considering various kinds of parameters in the scheduling problem, which belong to the NP-hard in computational complexity, we follow the heuristic algorithm to find the approximation solution. The solution algorithms include Earliest Due Date first rule, Earliest Start Time first rule. Base on these algorithms and considering task distribution, satellite position with angle of len to target images and satellite routing with high speed. The results indicate that the third algorithm, EST-modifying. In the EST-modifying algorithm in this research, we found EST-modifying algorithm have 56% improvement to get the approximation solution from the samples in this thesis. EST-modifying algorithm is a significant way to improve satellite imaging tasks solving by approximation solution.
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Lin, Wei-Cheng, and 林偉誠. "Satellite Imaging Scheduling: Algorithm Design and Application." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/79992600139205166733.
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博士國立臺灣大學
電機工程學研究所
93
This thesis presents the research and development of a novel imaging scheduling system for the newest generation of low-orbit, earth observation satellite, FORMOSAT-2. FORMOSAT-2 passes through Taiwan twice daily in approximately 10 minutes each time. The mission of FORMOSAT-2 is to perform near real-time, remote imaging of ocean and landmass in the vicinity of Taiwan. The daily imaging scheduling problem of FORMOSAT-2 includes considerations of various imaging requests (jobs) with different reward opportunities, changeover efforts between two consecutive imaging operations (tasks), cloud coverage effects, and the availability of satellite resource. It belongs to a class of single-machine scheduling problems with salient features of job-assembly characteristic, sequence-dependent setup effect, and the constraint of operating time window. The scheduling problem is first formulated as a monolithic integer programming problem, which is NP-hard in computational complexity. An approximation of the weighted penalty of incomplete jobs by penalties of individual tasks facilitates a separable integer programming problem. For problems of such high complexity, dynamic programming and exhaustive search techniques are either too time-consuming or impractical for optimal solutions. Rule-based or heuristic approaches can reduce the computation time drastically but the resultant optimality may be unsatisfactory. In view of the separable problem structure and researching findings about imaging scheduling of SPOT-5 in the literature, two solution approaches, Lagrangian relaxation and Tabu search, are adopted for novel solution algorithm design and investigation of their effectiveness. The Lagrangian relaxation algorithm design exploits the separable problem structure and relaxes coupling constraints with setup effect to decompose the problem into independent subproblem, each being a simple search for one task’s beginning imaging time within its time window. To solve the dual problem, Lagrangian multipliers are iteratively updated by subgradient (SG) method. For simplicity, a greedy-based feasibility adjustment heuristic is implemented to modify a dual solution into a feasible primal solution. It consists of constraint-violation resolving and task rescheduling. This heuristic is quick in computation and east to implement which exploits the separable problem structure and takes advantage of Lagrangian multipliers obtained from solving the dual. The Tabu search algorithm design integrates some important ideas including a greedy-based searching process, boundary extension by constraint relaxation, a dynamic Tabu tenure mechanism, intensification, and diversification. Core to three Tabu steps, Exploration, Intensification, and Diversification, are simply the greedy-based task’s insertion-and-removal process over partially constrained search space with the evaluation of primal objective function. Numerical results of 40 classes of 400 realistic instances indicate that Lagrangian relaxation algorithm achieves near-optimal dual solutions and has an advantage in computational efficiency. With the help of intensification and diversification, Tabu search algorithm is superior in optimality. Furthermore, two hybrid schemes, CASCADE and COMBINATION, are designed for performance improvement. CASCADE adopts Tabu search techniques to improve the solution quality of Lagrangian relaxation algorithm directly. COMBINATION then deals with the development of Tabu search-based feasibility adjustment heuristic in Lagrangian relaxation algorithm. Numerical results of 7 classes of 70 test cases for 10-minute scheduling time horizon indicate that the two hybrid algorithms improve the solution quality of Lagrangian relaxation algorithm significantly. Under the same TS iteration process (maximum iteration number and program), there are no significant differences on optimality among two hybrid algorithm and pure TS algorithm. It is concluded that the design of feasibility adjustment heuristic has significant impact on the performance of Lagrangian relaxation algorithm. Tabu search algorithm is independent on the initial schedule. Since using the solutions of Lagrangian relaxation algorithm as initial schedules to Tabu search algorithm did not bring better solutions. This is because the Diversification Tabu step has done exclusive exploration over diverse schedules, which helps Tabu search algorithm to escape from trapping in a local optimum. In conclusion, Tabu search algorithm design is good at solving the daily imaging scheduling problem of FORMOSAT-2.
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林秀蓉. "The Optimization Imaging Scheduling of Satellite with Inclinable Bservation." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/32562799142125977306.
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碩士國立新竹教育大學
人資處數學教育碩士班
98
Abstract FORMOSA-2 is a satellite with practical utility of the earth remote imaging and science experiment research. It is designed with daily coming againe property and high definition in high altitude. The satellite proceedes remote imaging in Taiwan and the land and sea area of all the world to promptly gets satellite imaging. It can satisfy different demand. The objective of the thesis research is to design a optimization scheduling algorithm to solve the job scheduling problem of the satellite. The jobs are recorded as coordinates. Satellite with inclinable observation on single orbit take job images between one consecutive imaging operation. Before taking images satellite must adjust its camera lens rangeing between -45 and 45 degreens on all sides. The objective is to get the maximum number of jobs in a limited resource of eight minutes. The scheduling problem is NP-hard in computational complexity. The thesis research presents a branch-and-bround algorithm to improve the processing of exhaustive attack method. Using effective upper bound, lower bound and dominance rules improve the solving quality and efficiency.Hope to get the optimal solution in a reasonable time. In the end ,simulating the computation experience with computer, the time and nodes of using branch-and-bound algorithms is superiour to exhaustive attack method in solving the remote imaging scheduling problem of the satellite.
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Feng, Ti Kan. "Combining Decomposition and Hybrid Algorithms for the Satellite Range Scheduling Problems." Thesis, 2012. http://hdl.handle.net/1807/32239.
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Multiple-resource satellite scheduling problem (MuRRSP) is a complex and difficult scheduling problem, which schedules a large number of task requests onto ground-station antennas in order to communicate with the satellites. We first examined several exact algorithms that were previously implemented in the machine scheduling field. They are column generation and logic-based Benders decomposition. A new hybrid approach that combines both column generation and logic-based Benders decomposition is proposed. The hybrid performed well when there is a large number of machines. Next, we presented a connection between the parallel machine scheduling problem and MuRRSP in order to solve MuRRSP with exact algorithms. Furthermore, we proposed a strengthened cut in the sub-problem of the logic-based Benders
decomposition. The resulting algorithm proved to be very effective. Barbulescu’s benchmark problems were solved and proved optimal with an average run-time less than one-hour. To the best of our knowledge, previous efforts to solve MuRRSP were all heuristic based and no optimal schedules existed.
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Lin, Ping-chun, and 林秉君. "The Analyses of Scheduling and Congestion Control in Broadband Satellite Network." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/89766623642665566346.
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碩士國立臺灣大學
電機工程學系研究所
86
Due to the inherent advantages and the emerging technology of the communic ation satellite, the concept of broadband satellite network (BSN) has become t he most potential network of global communications. We first discuss the s cheduling of downlink flows on the multibeam onboard processing satellite. In our model, the transponder can hop among zones with a little walk time which s hould be taken into consideration. We use MMPP model to analyze the performanc e of FCFS scheme and also to give an approximate solution of mean delay. Then the performance of some round-robin schemes are also analyzed by simulation. We investigate the threshold congestion control scheme based upon multi- rate server using Markov chain approach. Our analysis can be used to derive th e cell loss probability of ABR traffic. Through numerical analysis, we discuss the impact of service rate fluctuation on the performance of the congestion c ontrol. A new method for congestion control of ABR traffic in BSN is propos ed and its performance is examined by a simulation model. The results show tha t we can not only enhance the link utilization, but also reduce the number of feedback control signals. Besides, in our centralized controlled satellite com munication system, fairness can be easily achieved among all ABR connections.
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Yeh, Yi-Yao, and 葉憶瑤. "A Study of Developing Multi-Objective Optimization for Multi-Satellite Imaging Scheduling." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/bje68h.
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博士國防大學理工學院
國防科學研究所
101
The scheduling of satellite imaging increases in complexity with the need to satisfy additional constraints. A considerable amount of theoretical work has been carried out on single- or multi-satellite scheduling problems based on single-objective optimization. However, relatively little work has dealt with multi-objective optimization in a multi-satellite scheduling scenario. This paper proposes a novel imaging scheduling algorithm to provide mul-ti-objective optimization for multi-satellite. The concept of orbit coordination is introduced and geometry analysis is incorporated to obtain a Pareto front as a set of trade-off solutions. Moreover, this study developed a truncated Cauchy probability distribution function for the search algorithm as well as Ant Colony Optimization to efficiently obtain a sequence of tasking areas with imaging times. The proposed scheme is highly adaptive to real-world satellite imaging optimization problems and makes available a greater body of information to help the mission planners in the selection of final imaging plans.
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Schmidt, Marco. "Ground Station Networks for Efficient Operation of Distributed Small Satellite Systems." Doctoral thesis, 2011. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-64999.
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The field of small satellite formations and constellations attracted growing attention, based on recent advances in small satellite engineering. The utilization of distributed space systems allows the realization of innovative applications and will enable improved temporal and spatial resolution in observation scenarios. On the other side, this new paradigm imposes a variety of research challenges. In this monograph new networking concepts for space missions are presented, using networks of ground stations. The developed approaches combine ground station resources in a coordinated way to achieve more robust and efficient communication links. Within this thesis, the following topics were elaborated to improve the performance in distributed space missions: Appropriate scheduling of contact windows in a distributed ground system is a necessary process to avoid low utilization of ground stations. The theoretical basis for the novel concept of redundant scheduling was elaborated in detail. Additionally to the presented algorithm was a scheduling system implemented, its performance was tested extensively with real world scheduling problems. In the scope of data management, a system was developed which autonomously synchronizes data frames in ground station networks and uses this information to detect and correct transmission errors. The system was validated with hardware in the loop experiments, demonstrating the benefits of the developed approachSatellitenformationen und Konstellationen rücken immer mehr in den Fokus aktueller Forschung, ausgelöst durch die jüngsten Fortschritte in der Kleinsatelliten-Entwicklung. Der Einsatz von verteilten Weltraumsystemen ermöglicht die Realisierung von innovativen Anwendungen auf Basis von hoher zeitlicher und räumlicher Auflösung in Observationsszenarien. Allerdings bringt dieses neue Paradigma der Raumfahrttechnik auch Herausforderungen in verschiedenen Forschungsfeldern mit sich. In dieser Dissertation werden neue Netzwerk-Konzepte für Raumfahrtmissionen unter Einsatz von Bodenstationnetzwerken vorgestellt. Die präsentierten Verfahren koordinieren verfügbare Bodenstationsressourcen um einen robusten und effizienten Kommunikationslink zu ermöglichen. In dieser Arbeit werden dabei folgende Themenfelder behandelt um die Performance in verteilten Raumfahrtmissionen zu steigern: Das Verteilen von Kontaktfenster (sogenanntes Scheduling) in verteilten Bodenstationssystem ist ein notwendiger Prozess um eine niedrige Auslastung der Stationen zu vermeiden. Die theoretische Grundlage für das Konzept des redundanten Scheduling wurde erarbeitet. Zusätztlich wurde das Verfahren in Form eines Scheduling Systems implementiert und dessen Performance ausführlich an real-world Szenarien getestet. Im Rahmen des Themenfeldes Data Management wurde ein System entwickelt, welches autonom Datenframes in Bodenstationsnetzwerken synchronisieren kann. Die in den Datenframes enthaltene Information wird genutzt um Übertragungsfehler zu erkennen und zu korrigieren. Das System wurde mit Hardware-in-the-loop Experimenten validiert und die Vorteile des entwickelten Verfahrens wurden gezeigt
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Wilmans, Jared. "Design of a medium access protocol and scheduling algorithm for multimedia traffic over a DVB-RCS satellite link using a cross-layer approach." Thesis, 2010. http://hdl.handle.net/10413/5841.
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Satellite networks provide an alternative to terrestrial networks where cost and lack of infrastructure are driving parameters. For a satellite network to be cost effective one needs to be able to increase the efficiency of the network: this is accomplished by focusing on the parameters that affect the performance of the system and improving on them where possible. The factors affecting the network performance include the capacity, the propagation delay, the protocol used, and the channel error rate, among others. There are various ways to implement a satellite network depending on the satellite orbit, the architecture used, the access technique used, the radio interfaces used, etc.
This thesis work describes the chosen satellite standard, Digital Video Broadcasting – Return Channel via Satellite (DVB-RCS) and the associated Medium Access Control (MAC) protocols.
Two protocols were designed and investigated under ideal channel conditions, these being the Combined Free/Demand Assigned Multiple Access with Piggy Backing – Packet Dropping (CF/DAMA-PB-PD) protocol; and the Combined Free/Demand Assigned Multiple Access with Piggy Backing – Prioritised Earliest Deadline First (CF/DAMA-PB-PEDF) protocol, both derived from the Combined Free/Demand Assigned Multiple Access with Piggy Backing (CF/DAMA-PB) protocol.
The multimedia traffic models for voice, video and web classes are described, validated through simulations and presented; these provide the heterogeneous
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traffic required for evaluating the performance of the satellite system implemented and the designed protocols. Under the multimedia traffic, CF/DAMA-PB-PD was shown to excel in average packet delay reduction while reducing the overall system throughput. The CF/DAMA-PB-PEDF does not contribute to an improvement over the CF/DAMA-PB-PD protocol.
The effects of a non-ideal channel on the CF/DAMA-PB-PD protocol was investigated and presented along with the design of three MAC protocols that take the channel characteristics into account to improve on the system performance. The cross-layer interactions, more specifically the interaction between the physical and data–link layers, were used, investigated and presented. The channel state information in terms of signal-to-noise ratio (SNR) was used to improve the system performance.
The five protocols evaluated under non-ideal channel conditions were the CF/DAMA-PB, CF/DAMA-PB-PD, CF/DAMA-PB-BSNRF, CF/DAMA-PB-DD and the CF/DAMA-PB-BSNRF+DD. The best overall performance, both in average packet delay while maintaining good QoS levels and throughput was shown to be that of the CF/DAMA-PB-DD protocol.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.
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Oberholzer, Christiaan Vermaak. "Time-window optimization for a constellation of earth observation satellite." Thesis, 2009. http://hdl.handle.net/10500/2706.
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Thesis (M.Com.(quantitative Management))Satellite Scheduling Problems (SSP) are NP-hard and constraint programming and metaheuristics solution methods yield mixed results. This study investigates a new version of the SSP, the Satellite Constellation Time-Window Optimization Problem (SCoTWOP), involving commercial satellite constellations that provide frequent earth coverage. The SCoTWOP is related to the dual of the Vehicle Routing Problem with Multiple Timewindows, suggesting binary solution vectors representing an activation of time-windows. This representation fitted well with the MatLab® Genetic Algorithm and Direct Search Toolbox subsequently used to experiment with genetic algorithms, tabu search, and simulated annealing as SCoTWOP solution methods. The genetic algorithm was most successful and in some instances activated all 250 imaging time-windows, a number that is typical for a constellation of six satellites.
Quantitative Management
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Schor, Dario. "A Study of Particle Swarm Optimization Trajectories for Real-Time Scheduling." 2013. http://hdl.handle.net/1993/22020.
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Scheduling of aperiodic and independent tasks in hard real-time symmetric multiprocessing systems is an NP-complete problem that is often solved using heuristics like particle swarm optimization (PSO). The performance of these class of heuristics, known as evolutionary algorithms, are often evaluated based on the number of iterations it takes to find a solution. Such metrics provide limited information on how the algorithm reaches a solution and how the process could be accelerated.
This thesis presents a methodology to analyze the trajectory formed by candidate solutions in order to analyze them in both the time and frequency domains at a single scale. The analysis entails (i) the impact of different parameters for the PSO algorithm, and (ii) the evolutionary processes in the swarm. The work reveals that particles have a directed movement towards a solution during a transient phase, and then enter a steady state where they perform an unguided local search.
The scheduling algorithm presented in this thesis uses a variation of the minimum total tardiness with cumulative penalties cost function, that can be extended to suit different system needs. The experimental results show that the scheduler is able to distribute tasks to meet the real-time deadlines over 1, 2, and 4 processors and up to 30 tasks with overall system loads of up to 50\% in fewer than 1,000 iterations. When scheduling greater loads, the scheduler reaches local solutions with 1 to 2 missed deadlines, while larger tasks sets take longer to converge. The trajectories of the particles during the scheduling algorithm are examined as a means to emphasize the impact of the behaviour on the application performance and give insight into ways to improve the algorithm for both space and terrestrial applications.
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Lu, Chia-Hung, and 呂佳鴻. "An Multiple Scheduling Design of the LEO Satellite Tracking System Base on Fuzzy-Genetic-PID Control." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/25sck6.
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碩士國立高雄應用科技大學
電子工程系碩士班
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This thesis combines fuzzy theory with genetic algorithm with PID controller to set up a low-orbit satellites (LEO) tracking model. The LEO tracking system is controlled by an user interface, the mechanism including elevation axis, azimuth axis, tilt axis and resolvers antenna actual pointing coordinates. The proposed satellite tracking method is based on SGP4 orbit forecasting model generated by the antenna pointing database and follows the point coordinates to command the rotation of the axes. Gears rotation gap will affect the strength of the received signal. The genetic algorithm is used to optimize PID controller parameters, k_p、k_i and k_d, then the reduction of gears rotation gap errors is completed by the Fuzzy controller. The proposed Fuzzy-Genetic-PID controller has three advantages, the system performance is obtained from design of the fitness function; less complex expertise and the best solution is searched automatically. The experimental results illustrate that the errors reduction in elevation axis and azimuth axis are 36% and 54% with position control mode and speed control mode respectively, and this show our proposed Fuzzy-GA-PID controller is better than position control mode and speed control mode.
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(9187466), Bharath Kumar Comandur Jagannathan Raghunathan. "Semantic Labeling of Large Geographic Areas Using Multi-Date and Multi-View Satellite Images and Noisy OpenStreetMap Labels." Thesis, 2020.
Find full textAbstract:
This dissertation addresses the problem of how to design a convolutional neural network (CNN) for giving semantic labels to the points on the ground given the satellite image coverage over the area and, for the ground truth, given the noisy labels in OpenStreetMap (OSM). This problem is made challenging by the fact that -- (1) Most of the images are likely to have been recorded from off-nadir viewpoints for the area of interest on the ground; (2) The user-supplied labels in OSM are frequently inaccurate and, not uncommonly, entirely missing; and (3) The size of the area covered on the ground must be large enough to possess any engineering utility. As this dissertation demonstrates, solving this problem requires that we first construct a DSM (Digital Surface Model) from a stereo fusion of the available images, and subsequently use the DSM to map the individual pixels in the satellite images to points on the ground. That creates an association between the pixels in the images and the noisy labels in OSM. The CNN-based solution we present yields a 4-8% improvement in the per-class segmentation IoU (Intersection over Union) scores compared to the traditional approaches that use the views independently of one another. The system we present is end-to-end automated, which facilitates comparing the classifiers trained directly on true orthophotos vis-`a-vis first training them on the off-nadir images and subsequently translating the predicted labels to geographical coordinates. This work also presents, for arguably the first time, an in-depth discussion of large-area image alignment and DSM construction using tens of true multi-date and multi-view WorldView-3 satellite images on a distributed OpenStack cloud computing platform.
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Axmann, Robert [Verfasser]. "Interactive acquisition scheduling for low earth orbiting satellites / Robert Axmann." 2010. http://d-nb.info/100634098X/34.
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