Dissertations / Theses on the topic 'Space tracking'
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Grelck, John, Eldon Ehrsam, and James A. Means. "Space Tracking Systems/ Options Study." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/611727.
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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, CaliforniaThis paper presents the findings of the Space Tracking Systems/Options Study (STS/OS) and indicates its impact on the telemetering community. The STS/OS was commissioned by Air Force Test & Evaluation (AF/TE) to develop a long range plan (vision and roadmap) for the AF Test & Evaluation (T&E) community to ensure affordable capabilities (telemetry, tracking and commanding) for the future (2003-2008). The study was conducted by the Air Force Materiel Command (AFMC), Space & Missile Systems Center (SMC), Detachment 9, at Vandenberg AFB (VAFB), with support from the primary AFMC T&E centers, the Air Force Operational Test & Evaluation Command (AFOTEC), and the Air Force Space Command (AFSPC). Both "open air" aeronautical and astronautical test needs were considered. The study solicited requirements for existing and future programs, extrapolated existing and planned test capabilities out into the future, then compared the two to identify future shortfalls in capabilities and specific actions that are necessary to insure that the future program needs can be met. Three critical types of testing were identified that cannot be satisfied with existing or planned instrumentation. These are: large area testing (LAT), over the horizon testing (OTH), and space weapons testing (SWT). A major deficiency was also uncovered in end game scoring for air and space intercepts, where inadequate capability exists to perform the required vector miss-distance measurement. This paper is important to the telemetering community because it identifies the Global Positioning System (GPS) as the primary time space position information (TSPI) system for all future open air testing. GPS provides a passive capability that permits each vehicle to determine its own precise TSPI. Means must be provided, however, for the vehicle to relay its position to the appropriate range control center. The paper shows that the problems with down linking telemetry, aircraft buss data, digital audio, digital video, and TSPI collectively represent the need for a very capable datalink. Likewise, the need to uplink commands, synthetic targets, synthetic backgrounds, and target control information also represents the need for a very capable datalink. With its extensive expertise in RF linkages, the telemetering community is ideally suited to address this need for a robust datalink for the future of T&E.
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Turner, W. C., and R. A. Potter. "UNATTENDED SPACE-DIVERSITY TELEMETRY TRACKING ANTENNA SYSTEM." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/608826.
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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, CaliforniaA remotely-operated ground telemetry tracking and receiving station is described. The station, operating in a space-diversity mode, is capable of reception and tracking both at VHF and at UHF. The station can be configured and operated from a distance of 240 km using a wide-band land data link. Uplink command at VHF is included as part of the station.
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Graziani, Alberto <1980>. "Troposphere Calibration Techniques for Deep Space Probe Tracking." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/3023/.
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Ground-based Earth troposphere calibration systems play an important role in planetary exploration, especially to carry out radio science experiments aimed at the estimation of planetary gravity fields. In these experiments, the main observable is the spacecraft (S/C) range rate, measured from the Doppler shift of an electromagnetic wave transmitted from ground, received by the spacecraft and coherently retransmitted back to ground. If the solar corona and interplanetary plasma noise is already removed from Doppler data, the Earth troposphere remains one of the main error sources in tracking observables.
Current Earth media calibration systems at NASA’s Deep Space Network (DSN) stations are based upon a combination of weather data and multidirectional, dual frequency GPS measurements acquired at each station complex. In order to support Cassini’s cruise radio science experiments, a new generation of media calibration systems were developed, driven by the need to achieve the goal of an end-to-end Allan deviation of the radio link in the order of 3×〖10〗^(-15) at 1000 s integration time.
The future ESA’s Bepi Colombo mission to Mercury carries scientific instrumentation for radio science experiments (a Ka-band transponder and a three-axis accelerometer) which, in combination with the S/C telecommunication system (a X/X/Ka transponder) will provide the most advanced tracking system ever flown on an interplanetary probe. Current error budget for MORE (Mercury Orbiter Radioscience Experiment) allows the residual uncalibrated troposphere to contribute with a value of 8×〖10〗^(-15) to the two-way Allan deviation at 1000 s integration time.
The current standard ESA/ESTRACK calibration system is based on a combination of surface meteorological measurements and mathematical algorithms, capable to reconstruct the Earth troposphere path delay, leaving an uncalibrated component of about 1-2% of the total delay.
In order to satisfy the stringent MORE requirements, the short time-scale variations of the Earth troposphere water vapor content must be calibrated at ESA deep space antennas (DSA) with more precise and stable instruments (microwave radiometers). In parallel to this high performance instruments, ESA ground stations should be upgraded to media calibration systems at least capable to calibrate both troposphere path delay components (dry and wet) at sub-centimetre level, in order to reduce S/C navigation uncertainties. The natural choice is to provide a continuous troposphere calibration by processing GNSS data acquired at each complex by dual frequency receivers already installed for station location purposes.
The work presented here outlines the troposphere calibration technique to support both Deep Space probe navigation and radio science experiments. After an introduction to deep space tracking techniques, observables and error sources, in Chapter 2 the troposphere path delay is widely investigated, reporting the estimation techniques and the state of the art of the ESA and NASA troposphere calibrations. Chapter 3 deals with an analysis of the status and the performances of the NASA Advanced Media Calibration (AMC) system referred to the Cassini data analysis. Chapter 4 describes the current release of a developed GNSS software (S/W) to estimate the troposphere calibration to be used for ESA S/C navigation purposes. During the development phase of the S/W a test campaign has been undertaken in order to evaluate the S/W performances. A description of the campaign and the main results are reported in Chapter 5. Chapter 6 presents a preliminary analysis of microwave radiometers to be used to support radio science experiments. The analysis has been carried out considering radiometric measurements of the ESA/ESTEC instruments installed in Cabauw (NL) and compared with the requirements of MORE. Finally, Chapter 7 summarizes the results obtained and defines some key technical aspects to be evaluated and taken into account for the development phase of future instrumentation.
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Ntawiniga, Frédéric. "Head Motion Tracking in 3D Space for Drivers." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25229/25229.pdf.
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Ce travail présente un système de vision par ordinateur capable de faire un suivi du mouvement en 3D de la tête d’une personne dans le cadre de la conduite automobile. Ce système de vision par ordinateur a été conçu pour faire partie d'un système intégré d’analyse du comportement des conducteurs tout en remplaçant des équipements et des accessoires coûteux, qui sont utilisés pour faire le suivi du mouvement de la tête, mais sont souvent encombrants pour le conducteur. Le fonctionnement du système est divisé en quatre étapes : l'acquisition d'images, la détection de la tête, l’extraction des traits faciaux, la détection de ces traits faciaux et la reconstruction 3D des traits faciaux qui sont suivis. Premièrement, dans l'étape d'acquisition d'images, deux caméras monochromes synchronisées sont employées pour former un système stéréoscopique qui facilitera plus tard la reconstruction 3D de la tête. Deuxièmement, la tête du conducteur est détectée pour diminuer la dimension de l’espace de recherche. Troisièmement, après avoir obtenu une paire d’images de deux caméras, l'étape d'extraction des traits faciaux suit tout en combinant les algorithmes de traitement d'images et la géométrie épipolaire pour effectuer le suivi des traits faciaux qui, dans notre cas, sont les deux yeux et le bout du nez du conducteur. Quatrièmement, dans une étape de détection des traits faciaux, les résultats 2D du suivi sont consolidés par la combinaison d'algorithmes de réseau de neurones et la géométrie du visage humain dans le but de filtrer les mauvais résultats. Enfin, dans la dernière étape, le modèle 3D de la tête est reconstruit grâce aux résultats 2D du suivi et ceux du calibrage stéréoscopique des caméras. En outre, on détermine les mesures 3D selon les six axes de mouvement connus sous le nom de degrés de liberté de la tête (longitudinal, vertical, latéral, roulis, tangage et lacet). La validation des résultats est effectuée en exécutant nos algorithmes sur des vidéos préenregistrés des conducteurs utilisant un simulateur de conduite afin d'obtenir des mesures 3D avec notre système et par la suite, à les comparer et les valider plus tard avec des mesures 3D fournies par un dispositif pour le suivi de mouvement installé sur la tête du conducteur.This work presents a computer vision module capable of tracking the head motion in 3D space for drivers. This computer vision module was designed to be part of an integrated system to analyze the behaviour of the drivers by replacing costly equipments and accessories that track the head of a driver but are often cumbersome for the user. The vision module operates in five stages: image acquisition, head detection, facial features extraction, facial features detection, and 3D reconstruction of the facial features that are being tracked. Firstly, in the image acquisition stage, two synchronized monochromatic cameras are used to set up a stereoscopic system that will later make the 3D reconstruction of the head simpler. Secondly the driver’s head is detected to reduce the size of the search space for finding facial features. Thirdly, after obtaining a pair of images from the two cameras, the facial features extraction stage follows by combining image processing algorithms and epipolar geometry to track the chosen features that, in our case, consist of the two eyes and the tip of the nose. Fourthly, in a detection stage, the 2D tracking results are consolidated by combining a neural network algorithm and the geometry of the human face to discriminate erroneous results. Finally, in the last stage, the 3D model of the head is reconstructed from the 2D tracking results (e.g. tracking performed in each image independently) and calibration of the stereo pair. In addition 3D measurements according to the six axes of motion known as degrees of freedom of the head (longitudinal, vertical and lateral, roll, pitch and yaw) are obtained. The validation of the results is carried out by running our algorithms on pre-recorded video sequences of drivers using a driving simulator in order to obtain 3D measurements to be compared later with the 3D measurements provided by a motion tracking device installed on the driver’s head.
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Jerome, Richard Carleton University Dissertation Engineering Electrical. "Performance analysis of space-based radar tracking techniques." Ottawa, 1990.
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Dundar, Ismail Ugur. "Improvement of a Space Surveillance Tracking Analysis Tool." Thesis, Luleå tekniska universitet, Rymdteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71905.
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Since the beginning of space exploration, the amount of space debris has increased with thedevelopment of new space technologies. In fact, when a collision happens, new space debris aregenerated. Hence, collision risk between space debris and operational satellites rises. The purpose ofa surveillance network system consists of the detection of space objects, their classification and theirtracking. To avoid collisions, space debris objects’ orbit must be computed with sufficient accuracy. The goal of this thesis is the improvement of a pre-existing Space Surveillance and Tracking AnalysisTool. The tool is able to simulate different observation scenarios for radar or optical observer,which can be space-based or ground-based. To enhance the orbit determination, an ExtendedSquare Root Information Filter is implemented and incremented with a Smoother. Smoothers havebeen implemented for the existing filters as well, such as the Extended Kalman Filter and theUnscented Kalman Filter. A bias estimation method was added as part of the OD for all filter types.Additionally, different outlier detection methods were implemented for the automatic detection ofoutliers within the measurement data. To find the optimum orbit determination interval, differentscenarios were considered in LEO, MEO and GEO orbits. The methods were implemented anddifferent scenarios for validation will be discussed. A wide discussion on the methods implementationand their validation on different scenarios is presented, together with a comparison of the orbitdetermination results with the other filters. All the recently implemented features increase the efficiency of the tool to simulate the differentscenarios and enhance the tracking of space debris objects.
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Fiusco, Francesco. "Improvement of a Space Surveillance and Tracking Analysis tool." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-247880.
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This thesis deals with the improvement of SPOOK (SPace Objects Observation and Kalmanltering), an orbit calculation tool developed by Airbus Defence and Space GmbH. The workdescribed in this thesis aims at improving the architecture and analysis capabilities of thesoftware on dierent levels: Design and build a framework that can use SPOOK as a calculation engine and use itscapabilities to build a complete SST system for man-made objects orbiting the Earth,providing commercial services (e.g. collision avoidance, visualization, re-entry analysis,etc.), catalog maintenance and simulations. A complete Python API was designed andimplemented, which makes now SPOOK a complete cataloguing system for man-madespace objects that can provide services to the end user; Estimate covariance information from TLE data published by the US Space Command(available e.g. on Space-track.org); Devise and validate metrics that can assess the quality of an orbit determination processautomatically, to ensure as small human interaction as possible; Preliminarily implement a fast Lambert problem solver.In addition to this, a variety of miscellaneous activities were performed.Detta examensarbete handlar om förbättringar av SPOOK (observation av rymdobjekt ochKalmanfiltrering), ett beräkningsverktyg för omloppsbanor utvecklat av Airbus Defence och Space GmbH. Detta arbete syftar till att förbättra arkitekturen hos programvaran och dess förmåga att utföra analys på olika nivåer:•Designa och bygga ett ramverk användes SPOOK som beräkningsmotor och använda dess kapacitet för att bygga ett komplett SST-system för konstgjorda material kretsande runt jorden, tillhandahålla kommersiella tjänster (e.g. undvika kollision, visualisering, analys av återinträde etc.), katalogunderhåll och simuleringar. En komplett Python-API designades och implementerades, som nu gör SPOOK till ett komplett katalogiseringssystem för konstgjorda rymdobjekt som kan tillhandahålla tjänster för slutanvändare;•Uppskatta kovariansen av TLE data publicerad av US Space Command (tillgängligt via Space-track.org);•Utforma och validera kvalitetskoefficienter som automatiskt kan bedöma kvaliteten hos uppskattningen av en omloppsbana och därmed minimera interaktionen med användaren;Preliminärt implementera en snabb lösare för Lambertproblem.
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Hrabe, Jan, and Sabina Hrabetova. "Fast optical tracking of diffusion in brain extracellular space." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-196897.
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Hoefener, Carl E. "GPS: THE LOGICAL TOOL FOR PRECISION TRACKING IN SPACE." International Foundation for Telemetering, 1991. http://hdl.handle.net/10150/613092.
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International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, NevadaAs we develop more space vehicles, a pressing requirement emerges to provide precision tracking information. This need for exact time and space-position information (TSPI) persists whether developing and testing space weapons or locating the precise position of intelligence-gathering satellites. Because this is a worldwide tracking requirement, the use of conventional tracking techniques such as radar is precluded. Fortunately the Global Positioning System (GPS) is now in place and can provide the tracking information required. GPS offers two techniques for tracking space vehicles. A GPS receiver can be installed on the vehicle to determine the position that is then relayed to a ground terminal, or a GPS frequency translator can be used to compute the vehicle position at the master groundsite. Since both techniques have been proven satisfactory, the specific tracking requirement determines the method selected. For the flight tests of the Exoatmospheric Reentry-Vehicle Interceptor Subsystem (ERIS), the GPS frequency translator technique is used. A GPS frequency translator is installed on the target (a reentry-vehicle launched on a Minuteman from Vandenberg), and a translator is also installed on the ERIS, which is launched from Meck Island in the Kwajalein Atoll. The GPS frequency translator approach was chosen for these tests for a variety of reasons, the most important of which were the limited instrumentation space on the target and interceptor, the extreme dynamics of the interceptor, the tracking accuracy required, and the range at which the operation must be tracked. For the tracking of orbiting satellites, a GPS receiver can be flown on the satellite with its derived position information continuously stored. This data can then be dumped as the satellite passes over a selected groundsite.
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Hrabe, Jan, and Sabina Hrabetova. "Fast optical tracking of diffusion in brain extracellular space." Diffusion fundamentals 2 (2005) 120, S. 1-2, 2005. https://ul.qucosa.de/id/qucosa%3A14461.
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Sharifi, Mohammad A. "Satellite to satellite tracking in the space-wise approach." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-28337.
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Alam, Sayeed Safayet. "Analysis of Eye-Tracking Data in Visualization and Data Space." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3473.
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Eye-tracking devices can tell us where on the screen a person is looking. Researchers frequently analyze eye-tracking data manually, by examining every frame of a visual stimulus used in an eye-tracking experiment so as to match 2D screen-coordinates provided by the eye-tracker to related objects and content within the stimulus. Such task requires significant manual effort and is not feasible for analyzing data collected from many users, long experimental sessions, and heavily interactive and dynamic visual stimuli. In this dissertation, we present a novel analysis method. We would instrument visualizations that have open source code, and leverage real-time information about the layout of the rendered visual content, to automatically relate gaze-samples to visual objects drawn on the screen. Since such visual objects are shown in a visualization stand for data, the method would allow us to necessarily detect data that users focus on or Data of Interest (DOI).
This dissertation has two contributions. First, we demonstrated the feasibility of collecting DOI data for real life visualization in a reliable way which is not self-evident. Second, we formalized the process of collecting and interpreting DOI data and test whether the automated DOI detection can lead to research workflows, and insights not possible with traditional, manual approaches.
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Hoefener, Carl E., and Lawrence Wells. "UTILIZING GPS FOR ULTRA-HIGH DYNAMIC VEHICLE TRACKING IN SPACE." International Foundation for Telemetering, 1986. http://hdl.handle.net/10150/615581.
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International Telemetering Conference Proceedings / October 13-16, 1986 / Riviera Hotel, Las Vegas, NevadaGPS will provide a very attractive means to track kinetic energy weapons in space for the Strategic Defense Initiative programs for system test and evaluation. However, the small size and very high dynamics of these vehicles complicate the use of GPS. This paper considers these issues and suggests a solution.
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Chen, Yifeng. "Control of a flexible space robot tracking a moving target." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/39725.
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Wang, Jue Computer Science & Engineering Faculty of Engineering UNSW. "Vehicle tracking using scale invariant features." Publisher:University of New South Wales. Computer Science & Engineering, 2008. http://handle.unsw.edu.au/1959.4/41290.
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Object tracking is an active research topic in computer vision and has appli- cation in several areas, such as event detection and robotics. Vehicle tracking is used in Intelligent Transport System (ITS) and surveillance systems. Its re- liability is critical to the overall performance of these systems. Feature-based methods that are used to represent distinctive content in visual frames are one approach to vehicle tracking. Existing feature-based tracking systems can only track vehicles under ideal conditions. They have difficulties when used under a variety of conditions, for example, during both the day and night. They are highly dependent on stable local features that can be tracked for a long time period. These local features are easily lost because of their local property and image noise caused by factors such as, headlight reflections and sun glare. This thesis presents a new approach, addressing the reliability issues mentioned above, tracking whole feature groups composed of feature points extracted with the Scale Invariant Feature Transform (SIFT) algorithm. A feature group in- cludes several features that share a similar property over a time period and can be tracked to the next frame by tracking individual feature points inside it. It is lost only when all of the features in it are lost in the next frame. We cre- ate these feature groups by clustering individual feature points using distance, velocity and acceleration information between two consecutive frames. These feature groups are then hierarchically clustered by their inter-group distance, velocity and acceleration information. Experimental results show that the pro- posed vehicle tracking system can track vehicles with the average accuracy of over 95%, even when the vehicles have complex motions in noisy scenes. It gen- erally works well even in difficult environments, such as for rainy days, windy days, and at night. We are surprised to find that our tracking system locates and tracks motor bikes and pedestrians. This could open up wider opportunities and further investigation and experiments are required to confirm the tracking performance for these objects. Further work is also required to track more com- plex motions, such as rotation and articulated objects with different motions on different parts.
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Kohlleppel, Robert [Verfasser]. "Ground moving target tracking with space-time adaptive radar / Robert Kohlleppel." Siegen : Universitätsbibliothek der Universität Siegen, 2015. http://d-nb.info/107199199X/34.
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Ho, Tzung-Hsien. "Pointing, acquisition, and tracking systems for free-space optical communication links." College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/6734.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.Thesis research directed by: Electrical 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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Zheng, Sue M. Eng Massachusetts Institute of Technology. "Tracking algorithms under boundary layer effects for free-space optical communications." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/53185.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 87-88).
Free-space optical communication requires accurate tracking to maintain links. The tracking problem between an aircraft and satellite becomes more difficult with the introduction of a turret on the aircraft for increased field-of-regard. In the case of a hemispherical turret, the disrupted airflow at the boundary layer can greatly distort the optical beam. A model of the communication link is created to compare the performance of several tracking algorithms. We investigate the best algorithm under various atmospheric conditions and signal-to-noise ratios.
by Sue Zheng.
M.Eng.
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Novosad, Sidney W. "Spectrum Utilization for the International Space Station Communications and Tracking Systems." International Foundation for Telemetering, 1987. http://hdl.handle.net/10150/615227.
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International Telemetering Conference Proceedings / October 26-29, 1987 / Town and Country Hotel, San Diego, CaliforniaOver its lifetime, the international Space Station Program will use a variety of communications and tracking systems which could span the frequency spectrum from VHF to optical wavelengths. Primary communications traffic will initially occur in the S-band and Ku-band regions. Tracking will initially consist mostly of L-band satellite links. As the demand for more C&T services increases in the growth phase, use of millimeter and optical wavelengths will be required. Although many issues remain to be resolved, the most significant interference concern at present is that of Ku-band space/space links between co-orbiting Space Station elements.
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Cirillo, Giovanni. "Space Surveillance and Tracking Tool: Implementation and Test of New Methods." Thesis, KTH, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-262030.
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In March 2019 the number of artificial objects bigger than 1 mm in orbit around the Earth is estimated to be more than 170 millions. Only a small fraction of them (0.03%) is catalogued. An impact of an operational satellite with one of these debris can damage the satellite and undermine its mission. So it is important to catalogue as many objects as possible in order to reduce the risk of a collisions. This is done by using the software tool Space Object Observations and Kalman Filtering (SPOOK), developed in Airbus Defence and Space in Friedrichshafen. The goal of this Master Thesis was to create newfunctionalities to this tool and improve the existing ones. In particular three main goals have been accomplished: • a new model for the lighting ratio has been built to take into account the occultation of the Sun due to a covering body (for example the Earth or the Moon) and itsinfluence on the solar radiation pressure, necessary to have a good model for orbit propagation; • a tracklet building algorithm has been built to distinguish different tracklets (consecutive observations of the same object along its orbit) as a starting point for the association of different measurements belonging to the same object at distant epochs, necessary to update a catalogue of space objects; • a model to take into account the process noise has been improved giving some suggestion on how to tune the different parameters for different kinds of orbit.I mars 2019 uppgick antalet konstgjorda föremål större än 1 mm i omloppsbana runt jorden till över 170 miljoner. Av dessa är endast en mycket liten andel (0.03%) katalogiserade. En kollision mellan en operativ satellit och ett annat föremål i bana kan helt eller delvis förstöra satelliten. För att reducera risken för kollisioner är det därför viktigt att katalogisera så många föremål som möjligt. Detta görs genom att använda programvaran "Space Object Observations and Kalman Filtering" (SPOOK), som utvecklats av företaget Airbus Defence and Space i Friedrichshafen, Tyskland. Målet med detta examensarbete var att skapa nya funktioner i programvara samt att förbättra de befintliga funktionerna. Tre huvudmål har uppnåtts: • En ny modell för ljusförhållandet har skapats för att ta hänsyn till ocklutationen av solen på grund av en täckande kropp (till exempel jorden eller månen) och dess påverkan på solstrålningstrycket på rymdfarkosten, vilket är nödvändigt för att ha en bra modell för hur omloppsbanan fortplantas • En algoritm för s.k. tracklets, flera observationer av samma föremål längs dess omlopp, har skapats i syfte att skilja mellan olika tracklets som utgångspunkt för bestämma vilka mätningar som tillhör samma föremål vid avlägsna epoker. Detta är nödvändigt för att korrekt kunna uppdatera katalogen över rymdföremål. • Modellen för att ta hänsyn till processbruset har förbättrats och förslag ges om hur man ställer in olika parametrar för olika slags omloppsbanor.
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Jefferies, Lisa N. "Tracking attention in space and time : the dynamics of human visual attention." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/11564.
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Attention is essential to everyday life: without some selective function to guide and limit the processing of incoming information, our visual system would be overwhelmed. A description of the spatiotemporal dynamics of attention is critical to our understanding of this basic human cognitive function and is the primary goal of this dissertation. In particular, the research reported here is aimed at examining two aspects of the spatiotemporal dynamics of attention: a) the rate at which the focus of attention is shrunk and expanded along with the factors that influence this rate, and b) the factors
governing whether attention is deployed as either a unitary or a divided focus. The present research examines the spatiotemporal dynamics of focal attention by monitoring the pattern of accuracy that occurs when participants attempt to identify two targets embedded in simultaneously presented streams of items. By asking participants to monitor these streams simultaneously, with the spatial and temporal positions of the two targets in the streams being varied incrementally, it is possible to index the extent of focal attention in both space and time. Chapter 2 develops this behavioural procedure and assesses the rate at which the focus of attention is contracted. A qualitative model is put forward and tested. Chapter 3 examines factors that modulate the temporal course of attentional narrowing in young adults who presumably can exercise efficient control of attentional processes. In contrast, Chapter 4 examines the effect of reduced attentional control by examining the same process in older adults. The second goal of this thesis was to examine whether focal attention is deployed as a unitary or a divided focus. These two perspectives are generally viewed as mutually exclusive. The alternative hypothesis pursued in Chapter 5 is that focal attention can be deployed as either a single, unitary focus or divided into multiple foci, depending on the observers mental set and on the task demands. The final chapter then combines and compares the findings across all experiments and evaluates how they fit in with current theories of visual attention.
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Schnorr, Andrea Verfasser], Torsten [Akademischer Betreuer] [Kuhlen, and Christoph [Akademischer Betreuer] Garth. "Feature tracking for space-filling structures / Andrea Schnorr ; Torsten Kuhlen, Christoph Garth." Aachen : Universitätsbibliothek der RWTH Aachen, 2021. http://d-nb.info/1230661697/34.
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Wittrock, Jason M. "Free-Electron Laser (FEL) utilization in space applications (ship-borne pointing accuracy, deep-space communications, and orbital debris tracking)." Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/10710.
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The U.S. Navy is currently conducting research which will support the production of a MW-class free-electron laser (FEL). The Navy's end-state goal is to design and implement a defense system capable of destroying a fast-flying, anti-ship cruise missile (ASCM) target. To this end, the necessity of ensuring accurate pointing control of the beam is required. The first part of this thesis focuses on the U.S. Navy's desired end-state and investigates the ability of feedback and feed-forward control methods to provide improved pointing accuracy to a beam director mounted on a naval vessel similar in size to that of a Ticonderoga-class cruiser while traversing through various sea-states. The second part of this thesis examines the feasibility of employing the FEL as a means of deep-space (Mars and beyond) communication and orbital debris removal and tracking of objects in low-earth orbit (LEO).
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Roca, Carceller Guillem. "Tracking environmental change in seagrass meadows: understanding indicator behaviour across space and time." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/325415.
Full textAbstract:
Nearshore marine ecosystems like seagrass meadows face a wide range of anthropogenic influences, impacting the system at different spatial and temporal scales. Managing these systems in the face of these pressures requires detailed knowledge of how seagrass habitats respond to these various threats. A plethora of useful indicators have been developed to help managers and policy makers track seagrass meadow health and status, detect environmental impacts or measure the effectiveness of management interventions. However, choosing between these indicators can often be a daunting task since they vary considerably in their overall behaviour in relation to ecosystem and environmental changes. This thesis assesses the most commonly employed seagrass indicators to determine if they are adequate and appropriate to the specific needs of coastal ecosystem management. This assessment is based on evaluating three fundamental characteristics of each indicator – the robustness of its response, the specificity or generality of its response, and the time of response. We use a variety of complementary approaches to explore indicator behaviour. In Chapter 3, we use field-based studies to assess how seagrass indicators respond to the construction of a breakwater in the vicinity of a Posidonia oceanica seagrass meadow. Chapters 4 and 5 examine long-term trends in seagrass indicators to improving water quality conditions after significant regional management interventions. In addition, in Chapter 6, we comprehensively review seagrass indicator responses to multiple stressors. Chapters 3, 4 and 5 focus largely on the Catalan Coast in the Mediterranean with Posidonia oceanica as a target species. Chapter 6 in contrast is a broad review of a wide range of indicators used across several seagrass species worldwide. A central learning across these studies was that the level of biological organisation of the indicator (i.e. Physiological, biochemical, growth, morphological, structural or demographic) is critical in determining the specificity or generality of response: the lower the level (e.g. biochemical), the most specific the response, while the higher the level (e.g. population, community), the wider the response. Thus, biochemical indicators are ideal to determine the identity or even the origin of a pressure while structural indicators, in contrast, are useful as generic indicators of declining conditions. Response times are also heavily determined by the level of organisation, particularly in the detection of improving environmental quality along the Catalan coast. Biochemical indicators responded unequivocally to water quality improvements observed both in the experimental field study (Chapter 3) as well as in the analysis of the long-term data series (Chapters 4 and 5). The meta-analysis confirmed that these trends in specificity and response time were not unique to Posidonia oceanica or the Catalan coast and highlighted the critical role of plant size in determining indicator time responses. Large species take considerably longer to register a response to environmental degradation as well as improvement – a critical factor that needs to be accounted for in designing monitoring programmes and interpreting ecosystem trends. Taken together, these results suggest that differences in the behaviour of seagrass indicators require that they should be carefully selected to match the objectives of management. Based on the results reported in this thesis, where different sets of indicators have been proven successful for given management objectives, we finally develop a simple decision tree to help managers chose the most reliable sets of indicators matching their objectives. Understanding the diversity of responses that seagrass indicators display can make them a powerful set of tools in the ecosystem manager’s toolkit. Carefully employed, they can serve as bespoke solutions to a wide range of management objectives as we seek to monitor and protect these vital ecosystems and coastal water quality in the face of increasing coastal pressures.Entendre com responen les fanerògames marines a les pressions, és clau per a poder gestionar tant els herbeis com les aigües costaneres. Actualment, disposem d’un gran nombre d’indicadors basats en fanerògames marines. Però, la manca d’informació sobre com responen als canvis ambientals, fa que no sigui fàcil escollir quins indicadors són els més adients per a cada tipus i objectiu de gestió. Aquesta tesi avalua les tres característiques bàsiques de la resposta dels indicadors més utilitzats als canvis ambientals: la robustesa de la resposta, la especificitat dels indicadors a diferents pressions i el temps de resposta. Per analitzar aquestes tres característiques, fem servir diferents aproximacions complementàries. Al capítol 3, analitzem la resposta de diferents indicadors a les obres d’ampliació del port de Blanes, situat just al costat d’un herbei de Posidonia oceanica. Als capítols 4 i 5, estudiem com responen els indicadors a la millora de la qualitat de l’aigua a la costa catalana. Finalment, al capítol 6, presentem una metaanàlisi que estudia com responen els indicadors a diferents factors d’estrès. De totes tres aproximacions, hem pogut comprovar que el nivell d’organització dels indicadors (i.e. bioquímic, estructural) és clau a l’hora de determinar el grau d’especificitat de la resposta dels indicadors a les pressions: generalment, a més baix nivell d’organització (e.g. bioquímic), més específica és la resposta i com més alt (e.g. demogràfic), més ampli és el rang de pressions que un indicador pot detectar. El temps de resposta dels indicadors varia també en funció del nivell d’organització dels indicadors, especialment, quan es tracta de la detecció de millores ambientals. A més a més, la metaanàlisi destaca la importància de la mida de les plantes per determinar el temps de resposta. Les espècies grans triguen més a detectar la degradació de les condicions ambientals i, molt més, a detectar la millora, especialment, si s’utilitzen indicadors estructurals o demogràfics. Basant-nos en els resultats d’aquesta tesi, hem elaborat un esquema per ajudar els gestors a escollir el conjunt d’indicadors que més s’ajusti a cada objectiu de gestió. Utilitzats correctament, aquests indicadors són molt útils per fer el seguiment, tant de l’estat de salut dels herbeis, com de la qualitat del medi.
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Persen, Todd. "FPGA-BASED DESIGN OF A MAXIMUM-POWER-POINT TRACKING SYSTEM FOR SPACE A." Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3126.
Full textAbstract:
Satellites need a source of power throughout their missions to help them remain operational for several years. The power supplies of these satellites, provided primarily by solar arrays, must have high efficiencies and low weights in order to meet stringent design constraints. Power conversion from these arrays is required to provide robust and reliable conversion which performs optimally in varying conditions of peak power, solar flux, and occlusion conditions. Since the role of these arrays is to deliver power, one of the principle factors in achieving maximum power output from an array is tracking and holding its maximum-power point. This point, which varies with temperature, insolation, and loading conditions, must be continuously monitored in order to react to rapid changes. Until recently, the control of maximum power point tracking (MPPT) has been implemented in microcontrollers and digital signal processors (DSPs). While DSPs can provide a reasonable performance, they do not provide the advantages that field-programmable gate arrays (FPGA) chips can potentially offer to the implementation of MPPT control. In comparison to DSP implementations, FPGAs offer lower cost implementations since the functions of various components can be integrated onto the same FPGA chip as opposed to DSPs which can perform only DSP-related computations. In addition, FPGAs can provide equivalent or higher performance with the customization potential of an ASIC. Because FPGAs can be reprogrammed at any time, repairs can be performed in-situ while the system is running thus providing a high degree of robustness. Beside robustness, this reprogrammability can provide a high level of (i) flexibility that can make upgrading an MPPT control system easy by merely updating or modifying the MPPT algorithm running on the FPGA chip, and (ii) expandability that makes expanding an FPGA-based MPPT control system to handle multi-channel control. In addition, this reprogrammability provides a level of testability that DSPs cannot match by allowing the emulation of the entire MPPT control system onto the FPGA chip. This thesis proposes an FPGA-based implementation of an MPPT control system suitable for space applications. At the core of this system, the Perturb-and-observe algorithm is used to track the maximum power point. The algorithm runs on an Alera FLEX 10K FPGA chip. Additional functional blocks, such as the ADC interface, FIR filter, dither generator, and DAC interface, needed to support the MPPT control system are integrated within the same FPGA device thus streamlining the part composition of the physical prototype used to build this control system.M.S.E.E.
Department of Electrical and Computer Engineering
Engineering and Computer Science
Electrical Engineering
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Lollini, Emanuele. "Analysis of multi-station technique for noise reduction in Deep Space Doppler tracking." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amslaurea.unibo.it/25914/.
Full textAbstract:
Precision measurements of spacecraft range-rate enabled by two-way microwave links are used in navigation and in radio science experiments as planetary geodesy. The final accuracies in the observables depend almost linearly on the Doppler noise in the link. Among all the types of noise that enter a Doppler measurement, the most important are thermal noise, spacecraft antenna buffeting and ground antenna mechanical noise. Several effects at different time scales are responsible for the antenna mechanical noise, such as wind loading, bulk motion due to irregularities in the supporting azimuth ring, unmodeled subreflector motion and long-term differential thermal expansion. Therefore, it is not always simple to prevent and relieve this source of noise.
The following thesis is aimed at improve the Doppler measurements exploiting a noise-cancellation technique proposed by John W. Armstrong et al. and elaborated by Virginia Notaro et al. from the mechanical and aerospace engineering department at the Sapienza University. The Time-Delay Mechanical Noise Cancellation (TDMC) technique consists in a combination of Doppler measurements given by a two-way antenna and an additional one which should be stiffer, smaller and placed in a site with good tropospheric conditions. The antenna considered for the two-way link is the DSS 25 in Goldstone, CA from NASA; for the three-way antenna has been taken the 12-m Atacama Pathfinder Experiment (APEX) in Chajnantor, Chile. The simulation is performed for a 1000 s integration time.
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Ricci, Ester. "The passage from microstrip to pixel silicon detectors for tracking particles in space." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/250674.
Full textAbstract:
Tracking particle in space is a crucial instance on a large number of space experiments. Measurements of charged cosmic rays based on spectrometers, observation of γ-rays, study of space weather and many other applications require systems equipped with tracking detectors. The sensitive area of detectors required for tracking spans from cm2 to m2. Silicon microstrip detectors have been the elective technology for tracking particles in space for several decades. Their stability, reliability and low power consumption are supported by years of expertise and provided a vast number of significant results on fundamental physics, reached with different experiments. An example of magnetic spectrometers is AMS-02, operated on International Space Station, and the satellite-borne PAMELA, that measure the charged component of cosmic rays and use tracking planes immersed in a magnetic field produced by permanent magnets to discriminate matter from antimatter. AMS-02 mounts several squared meters of microstrip tracker. The strip technology also has some limits. The spatial resolution depends on the pitch of the strips implanted on silicon buffer, that depends on the capabilities of the facility in charge of device construction. The fabrication sites have to use dedicated infrastructures, making costs relatively higher than in the past. Moreover, it is difficult to reduce the detector thickness below about 150 μm. This thickness impacts on measurements because of multiple scattering and reduces the lower threshold of low energy nuclear experiments. Another problem arises when the detector operates in radiation-dense environment. When the same frame shows multiple hits, the correct reconstruction of each interaction point is subject to degeneracy, due to the ambiguity in associating x− and y−hits in the microstrip sensor. The problem worsens if we consider that microstrips show equivalent charge noise generally up to hundreds of electrons if we take into account all the contributions from readout electronics. The resulting signal-to-noise ratio is generally good, but rarely exceeding 10 for Minimum Ionising Particles (MIP). The migration towards a new technology based on pixel devices is interesting because it solves some of these limitations. In particular, the hit position is uniquely defined by the position of the pixels involved in the event and pixel detectors can be thinned down to about 50 μm, with a potential gain in resolution. This thesis focuses on Monolithic Active Pixel Sensors (MAPS). They have the advantage, with respect to both the microstrip detectors and the other pixel families, of having the first stages of readout (front-end amplification, discrimination, digitisation and zero suppression) included on the sensor substrate. The detectors are realised with standard CMOS technology, the same used by foundries for most of commercial applications. Once the design is defined, the mass production of the devices is possible, and it reduces the cost of the single detector. Other pixel detectors do not provide this advantage since the design of sensors is based on different custom technologies, and after the production, the detector must be bump bonded to a readout chip, an expensive and low-yield technique. MAPS also have some limits. The most critical for the use in space is power consumption. A second relevant problem to face is that most of the devices realised with this technique have a digital readout, that does not allow measurement of dE/dx, important for particle identification. The requirement of space experiments to cover large surfaces with a tracking detector implies that using pixels the number of channels to handle increases. MAPS approach solves this issue by including on the detector a smart readout that passes to the DAQ system only data from pixels interested by the event. The MAPS detectors have been proposed for the first time at the end of the nineties. The technology reached maturity in the last years. The ALICE experiment, first of the four main LHC experiments, have installed MAPS detectors for its Inner Tracker Upgrade. For the upgrade the collaboration designed a new MAPS detector, ALPIDE. It is realised by TowerJazz foundry in 180 nm technology. The pixel pitch is 28 μm. The matrix is composed of 512×1024 pixels, for a total surface of 1.5×3 cm2. Although smaller if compared to microstrip ladders, that can reach several tenths of squared cm, the ALPIDE is one of the largest detector realised with this technology. Among the properties of ALPIDE, one particularly interesting for the space application is low power consumption. In ALICE, the low power consumption is required because of the difficulties of power distribution and cooling of the Inner Tracker. The power density is still one order of magnitude higher than for microstrip, but it starts to be interesting for space applications. In this thesis, we explore the possibility to use ALPIDE to realise the tracker for the second High Energy Particle Detector (HEPD-02), a payload of the second China Seismo-Electromagnetic Satellite (CSES-02). The CSES constellation is devoted to the observation of Earth from space and in particular to the study of ionosphere perturbation that might be related to seismic activity on Earth. We organised the study into two parts. The first is dedicated to the optimisation of the detector for space, dealing with the power consumption reduction, thermal control and space compliance tests, another section is devoted to the study of the ALPIDE response to low energy nuclei. The section devoted to space compliance starts with a description of the strategies for power consumption reduction. Some strategies are applied to the detector (use of low-speed lines, smart clock distribution) and require an optimised design of the full tracker and trigger. The design of the different sub-detectors allows distribution of the clock only to a limited section that has a higher probability of being involved in the event. With this approach, we can keep the power consumption of the full tracker below 10 W, as required by the design limits. High power consumption has a large impact on the temperature control of the device. The ALPIDE has an ideal operative temperature of about 30◦, which must be kept constant on the whole detector. ALICE cools down the detector with a water-based system, a solution not applicable in space, where convection is discouraged. A carbon fibre cold plate, designed to optimise the thermal conduction, is applied to control the temperature. The carbon fibre placement is studied to minimise the thickness of the plate and the impact of inert material on tracking performance. The thesis reports the results of various tests of space compliance made on a modified ALICE tracker module, an engineering model of the HEPD-02 module. It was made of 14 ALPIDE detectors disposed into two columns and glued and wire bonded to a Flexible Printed Circuit (FPC). On the other side, the detectors are glued to a carbon fibre plate. The device has been tested according to the requirements of the Chinese Space Agency for vibrations and in thermal-vacuum. A study of the response of the detector to low energy nuclei has been also carried out. The HEPD-02 detector is devoted to the detection of electrons between 3 and 150 MeV and protons between 30 and 300 MeV. We base the study on measurements, taken with protons and low energy nuclei at different test facilities in Italy, as well as simulations. Measurements have been analysed with different tools and used to build a model of the detector response. The only observable of the detector is the cluster, and in particular on the cluster size, i.e. the number of pixels over the set threshold for each interaction. The analysis characterises the dependence of the cluster dimension on the energy deposited in silicon by the particle. The energy release inside ALPIDE has been evaluated using GEANT4 simulations of the beam tests. The values obtained have been used as an input for the analysis and to initialise the charge diffusion process in the device in a second simulation tool, Synopsis TCAD. The TCAD simulation includes the electrical properties of silicon and reproduces the detector structure and the electrical property of the materials. The simulation results have been used to verify our knowledge of the detector details, evaluated as the capability of the simulation to reproduce the experimental data. The simulation is the base of a tool that I developed to predict the cluster size as a function of a given number of parameters. This tool works after the GEANT4 simulation and provides essential information for the event reconstruction software of the experiment. In conclusion, this work reports on space compliance tests performed on the ALPIDE sensor, demonstrating technology readiness level 7 on the scale of space agencies. The dependence of the observed cluster size on the energy deposit has been fully characterised for highly ionising particles. This parametrisation will be a crucial element of the event reconstruction and particle identification algorithms of the HEPD-02 experiment. Given the energy of the nuclei under consideration, this study contains information useful for applications in proton and hadrotherapy.
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Halterman, R. Ryan. "Observation and tracking of tropical cyclones using resolution enhanced scatterometry /." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1667.pdf.
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De, Wet Sarel Joubert. "Development of a system for tracking objects in a confined space / S.J. de Wet." Thesis, North-West University, 2009. http://hdl.handle.net/10394/4010.
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Tam, Tapia Augusto José. "Space craft reliable trajectory tracking and landing using model predictive control with chance constraints." Master's thesis, Pontificia Universidad Católica del Perú, 2017. http://tesis.pucp.edu.pe/repositorio/handle/123456789/8897.
Full textAbstract:
This work considers the study of chance constrained Model Predictive Control (MPC)
for reliable spacecraft trajectory tracking and landing.
Objectives of the master thesis: • To identify and study mathematical dynamic models of a spacecraft.
• To study the trajectory design and landing schemes for a given mission.
• To study the source of uncertainty in the model parameters and external disturbances.
• To study the chance constrained MPC scheme for the reliable and optimal trajectory
tracking and landing.
• To testing the new analytic approximation approaches, Inner and Outer, for chance
constraints.
• To study appropriate MPC algorithms and implement on case-studies.
In the first part of the thesis considers deterministic dynamical models of spacecraft are
discussed.
The first example is about the tracking of trajectory and soft landing on the surface of
an asteroid EROS433, this model uses Cartesian coordinates.
In the second example, in a similar way to the first example, the trajectory and soft
landing is performed on the surface of a celestial body. It is assumed that the celestial
body is a perfect sphere, something that does not happen in the first example. Thus,
the second example uses a Spherical coordinate system.
The third example is about a Lander that enters the Martian atmosphere. This Lander
follows a designed trajectory until reaching a certain altitude over the Martian surface.
At this altitude the Lander deploys a parachute to make the landing.
To solve the deterministic examples described above, the following sequence of steps are:
• pose the deterministic Nonlinear Optimal Control Problem (NOCP),
• convert the infinite Optimal Control Problem (OCP) to a finite Nonlinear Programming
Problem (NLP), applying the Runge-Kutta 4th order discretization
method,
• apply the Quasi-sequential method to the deterministic NLP obtained from the
previous step,
• solution of the reduced NLP obtained from the previous step using IpOpt software. The steps outlined above are also part of the Nonlinear Model Predictive Control (NMPC)
approach.
In the second part of the thesis, the same examples of the first part are used but now
with stochastic variables. To find the control law in each model, the stochastic NMPC
was used. The above mentioned approach begins with a chance constrained OCP.
The latter is discretized obtaining an NLP. The problem with this NLP, with chance
constraints, is that is very difficult to solve in analytic form. So these chance constraints
are approached by a different method that exist in the state of the art. This thesis
work is focused on approaching the chance constraints through Analytic Approximation
Strategies, specifically by the recent: Inner and Outer Approximation methods.
The chance constrained MPC is expensive from a computational point of view, but it
allows to find a control law for a more reliable trajectory-tracking and soft landing .
That is suitable for applications with random disturbances, model inaccuracies, and
measurement errors.Tesis
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Prisacariu, Victor Adrian. "Shape knowledge for segmentation and tracking." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:68dd7205-219a-45e1-830d-f55e530ed8aa.
Full textAbstract:
The aim of this thesis is to provide methods for 2D segmentation and 2D/3D tracking, that are both fast and robust to imperfect image information, as caused for example by occlusions, motion blur and cluttered background. We do this by combining high level shape information with simultaneous segmentation and tracking. We base our work on the assumption that the space of possible 2D object shapes can be either generated by projecting down known rigid 3D shapes or learned from 2D shape examples. We minimise the discrimination between statistical foreground and background appearance models with respect to the parameters governing the shape generative process (the 6 degree-of-freedom 3D pose of the 3D shape or the parameters of the learned space). The foreground region is delineated by the zero level set of a signed distance function, and we define an energy over this region and its immediate background surroundings based on pixel-wise posterior membership probabilities. We obtain the differentials of this energy with respect to the parameters governing shape and conduct searches for the correct shape using standard non-linear minimisation techniques. This methodology first leads to a novel rigid 3D object tracker. For a known 3D shape, our optimisation here aims to find the 3D pose that leads to the 2D projection that best segments a given image. We extend our approach to track multiple objects from multiple views and propose novel enhancements at the pixel level based on temporal consistency. Finally, owing to the per pixel nature of much of the algorithm, we support our theoretical approach with a real-time GPU based implementation. We next use our rigid 3D tracker in two applications: (i) a driver assistance system, where the tracker is augmented with 2D traffic sign detections, which, unlike previous work, allows for the relevance of the traffic signs to the driver to be gauged and (ii) a robust, real time 3D hand tracker that uses data from an off-the-shelf accelerometer and articulated pose classification results from a multiclass SVM classifier. Finally, we explore deformable 2D/3D object tracking. Unlike previous works, we use a non-linear and probabilistic dimensionality reduction, called Gaussian Process Latent Variable Models, to learn spaces of shape. Segmentation becomes a minimisation of an image-driven energy function in the learned space. We can represent both 2D and 3D shapes which we compress with Fourier-based transforms, to keep inference tractable. We extend this method by learning joint shape-parameter spaces, which, novel to the literature, enable simultaneous segmentation and generic parameter recovery. These can describe anything from 3D articulated pose to eye gaze. We also propose two novel extensions to standard GP-LVM: a method to explore the multimodality in the joint space efficiently, by learning a mapping from the latent space to a space that encodes the similarity between shapes and a method for obtaining faster convergence and greater accuracy by use of a hierarchy of latent embeddings.
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Johansson, Anders. "Acoustic Sound Source Localisation and Tracking : in Indoor Environments." Doctoral thesis, Blekinge Tekniska Högskola [bth.se], School of Engineering - Dept. of Signal Processing, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00401.
Full textAbstract:
With advances in micro-electronic complexity and fabrication, sophisticated algorithms for source localisation and tracking can now be deployed in cost sensitive appliances for both consumer and commercial markets. As a result, such algorithms are becoming ubiquitous elements of contemporary communication, robotics and surveillance systems. Two of the main requirements of acoustic localisation and tracking algorithms are robustness to acoustic disturbances (to maximise localisation accuracy), and low computational complexity (to minimise power-dissipation and cost of hardware components). The research presented in this thesis covers both advances in robustness and in computational complexity for acoustic source localisation and tracking algorithms. This thesis also presents advances in modelling of sound propagation in indoor environments; a key to the development and evaluation of acoustic localisation and tracking algorithms. As an advance in the field of tracking, this thesis also presents a new method for tracking human speakers in which the problem of the discontinuous nature of human speech is addressed using a new state-space filter based algorithm which incorporates a voice activity detector. The algorithm is shown to achieve superior tracking performance compared to traditional approaches. Furthermore, the algorithm is implemented in a real-time system using a method which yields a low computational complexity. Additionally, a new method is presented for optimising the parameters for the dynamics model used in a state-space filter. The method features an evolution strategy optimisation algorithm to identify the optimum dynamics’ model parameters. Results show that the algorithm is capable of real-time online identification of optimum parameters for different types of dynamics models without access to ground-truth data. Finally, two new localisation algorithms are developed and compared to older well established methods. In this context an analytic analysis of noise and room reverberation is conducted, considering its influence on the performance of localisation algorithms. The algorithms are implemented in a real-time system and are evaluated with respect to robustness and computational complexity. Results show that the new algorithms outperform their older counterparts, both with regards to computational complexity, and robustness to reverberation and background noise. The field of acoustic modelling is advanced in a new method for predicting the energy decay in impulse responses simulated using the image source method. The new method is applied to the problem of designing synthetic rooms with a defined reverberation time, and is compared to several well established methods for reverberation time prediction. This comparison reveals that the new method is the most accurate.
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Cevher, Volkan. "A Bayesian Framework for Target Tracking using Acoustic and Image Measurements." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6824.
Full textAbstract:
Target tracking is a broad subject area extensively studied in many engineering disciplines. In this thesis, target tracking implies the temporal estimation of target features such as the target's direction-of-arrival (DOA), the target's boundary pixels in a sequence of images, and/or the target's position in space. For multiple target tracking, we have introduced a new motion model that incorporates an acceleration component along the heading direction of the target. We have also shown that the target motion parameters can be considered part of a more general feature set for target tracking, e.g., target frequencies, which may be unrelated to the target motion, can be used to improve the tracking performance. We have introduced an acoustic multiple-target tracker using a flexible observation model based on an image tracking approach by assuming that the DOA observations might be spurious and that some of the DOAs might be missing in the observation set. We have also addressed the acoustic calibration problem from sources of opportunity such as beacons or a moving source. We have derived and compared several calibration methods for the case where the node can hear a moving source whose position can be reported back to the node.
The particle filter, as a recursive algorithm, requires an initialization phase prior to tracking a state vector. The Metropolis-Hastings (MH) algorithm has been used for sampling from intractable multivariate target distributions and is well suited for the initialization problem. Since the particle filter only needs samples around the mode, we have modified the MH algorithm to generate samples distributed around the modes of the target posterior. By simulations, we show that this mode hungry algorithm converges an order of magnitude faster than the original MH scheme. Finally, we have developed a general framework for the joint state-space tracking problem. A proposal strategy for joint state-space tracking using the particle filters is defined by carefully placing the random support of the joint filter in the region where the final posterior is likely to lie. Computer simulations demonstrate improved performance and robustness of the joint state-space when using the new particle proposal strategy.
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Li, Ni. "Vision based trajectory tracking of space debris in close proximity via integrated estimation and control." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4966.
Full textAbstract:
Since the launch of the first rocket by the scientists during the World War II , mankind continues their exploration of space. Those space explorations bring the benefits to human, such as high technology products like GPS, cell phone, etc. and in-depth insight of outside of the earth. However, they produce millions of debris with a total estimated mass of more than 3,000,000 kg in the space around the earth, which has and will continue to threat the safety of manned or unmanned space exploration. According to the research, at least tens of spacecraft were considered been damaged or destroyed by the debris left in the space. Thus, the increasingly cluttered environment in space is placing a premium on techniques capable of tracking and estimating the trajectory of space debris. Among debris, the pieces smaller than 1cm are unable to damage spacecraft because of the crafts' shields, while the pieces larger than 10cm can be tracked by ground-based radars or a radar network. However, unlike the debris within these size ranges, the debris larger than 1 cm and smaller than 10 cm are able to hurt the shield of space craft and are hard to be detected by the exiting technical equipments because of their small size and cross-section area. Accordingly it is always a challenge for spacecraft or satellite mission designers to consider explicitly the ones ranged from 1 cm to 10 cm a priori.; To tackle this challenge, a vision based debris' trajectory tracking method is presented in the thesis. Unlike radar tracking, vision based tracking doesn't require knowledge of a debris' cross-section, regardless of its size. In this work, two cameras onboard of satellites in a formation are used to track the debris in close proximity. Also to differentiate the target debris from other clutters (i.e. the debris that are not tracked intentionally), a data association technique is investigated. A two-stage nonlinear robust controller is developed to adjust the attitude of the satellites such that the target debris is always inside of the field of view of the cameras. Capabilities of the proposed integrated estimation and control methods are validated in the simulations.ID: 029809810; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references (p. 41-48).
M.S.
Masters
Mechanical, Materials, and Aerospace Engineering
Engineering and Computer Science
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Eisenberg, Rebecca Nicole. "Reexamining the Global Cold War in South Africa: Port Usage, Space Tracking and Weapons Sales." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/117.
Full textAbstract:
The global Cold War is used frequently by historians to frame the context of political, economic, social, military, and geographic history of the 20th century. This is often the case in Africa as well. This thesis set out to explore U.S.- South African relations during the 1960s. After conducting research in Record Group 59 (State Department Records) of the National Archives from 1967-1973, three case studies emerged that suggested that reexamination of how historians traditionally view U.S.-South African relations during this time period is necessary. The three case studies include U.S. use of naval ports in South Africa, the strategic geographic location of South Africa and its importance to NASA's satellite and missile tracking stations, and the policy of selling of weapons to South Africa by the U.S. While this is by no means an exhaustive study of this time period due to limited time in the National Archives, it does offer promise for more research involving this topic.
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He, Chao. "Advanced wavelet application for video compression and video object tracking." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1125659908.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xvii, 158 p.; also includes graphics (some col.). Includes bibliographical references (p. 150-158). Available online via OhioLINK's ETD Center
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Ackerman, Samuel. "A Probabilistic Characterization of Shark Movement Using Location Tracking Data." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/499173.
Full textAbstract:
StatisticsPh.D.
Our data consist of measurements of 22 sharks' movements within a 366-acre tidal basin. The measurements are made at irregular time points over a 16-month interval. Constant-length observation intervals would have been desirable, but are often infeasible in practice. We model the sharks' paths at short constant-length intervals by inferring their behavior (feeding vs transiting), interpolating their locations, and estimating parameters of motion (speed and turning angle) in environmental and ecological contexts. We are interested in inferring regional differences in the sharks' behavior, and behavioral interaction between them. Our method uses particle filters, a computational Bayesian technique designed to sequentially model a dynamic system. We discuss how resampling is used to approximate arbitrary densities, and illustrate its use in a simple example of a particle filter implementation of a state-space model. We then introduce a particular model formulation that uses conditioning to introduce unobserved parameters for the shark's behaviors. We show how the irregularly-observed shark locations can be modeled by interpolation as a set of movements at constant-length time intervals. We use a spline method for generating approximations of the ground truth at these intervals for comparison with our model. Finally, we demonstrate our model's estimates of the sharks' behavioral and ecological parameters of interest on a subset of the observed data.
Temple University--Theses
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Popovic, Jelena. "Fast Adaptive Numerical Methods for High Frequency Waves and Interface Tracking." Doctoral thesis, KTH, Numerisk analys, NA (stängd 2012-06-30), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105062.
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The main focus of this thesis is on fast numerical methods, where adaptivity is an important mechanism to lowering the methods' complexity. The application of the methods are in the areas of wireless communication, antenna design, radar signature computation, noise prediction, medical ultrasonography, crystal growth, flame propagation, wave propagation, seismology, geometrical optics and image processing. We first consider high frequency wave propagation problems with a variable speed function in one dimension, modeled by the Helmholtz equation. One significant difficulty of standard numerical methods for such problems is that the wave length is very short compared to the computational domain and many discretization points are needed to resolve the solution. The computational cost, thus grows algebraically with the frequency w. For scattering problems with impenetrable scatterer in homogeneous media, new methods have recently been derived with a provably lower cost in terms of w. In this thesis, we suggest and analyze a fast numerical method for the one dimensional Helmholtz equation with variable speed function (variable media) that is based on wave-splitting. The Helmholtz equation is split into two one-way wave equations which are then solved iteratively for a given tolerance. We show rigorously that the algorithm is convergent, and that the computational cost depends only weakly on the frequency for fixed accuracy. We next consider interface tracking problems where the interface moves by a velocity field that does not depend on the interface itself. We derive fast adaptive numerical methods for such problems. Adaptivity makes methods robust in the sense that they can handle a large class of problems, including problems with expanding interface and problems where the interface has corners. They are based on a multiresolution representation of the interface, i.e. the interface is represented hierarchically by wavelet vectors corresponding to increasingly detailed meshes. The complexity of standard numerical methods for interface tracking, where the interface is described by marker points, is O(N/dt), where N is the number of marker points on the interface and dt is the time step. The methods that we develop in this thesis have O(dt^(-1)log N) computational cost for the same order of accuracy in dt. In the adaptive version, the cost is O(tol^(-1/p)log N), where tol is some given tolerance and p is the order of the numerical method for ordinary differential equations that is used for time advection of the interface. Finally, we consider time-dependent Hamilton-Jacobi equations with convex Hamiltonians. We suggest a numerical method that is computationally efficient and accurate. It is based on a reformulation of the equation as a front tracking problem, which is solved with the fast interface tracking methods together with a post-processing step. The complexity of standard numerical methods for such problems is O(dt^(-(d+1))) in d dimensions, where dt is the time step. The complexity of our method is reduced to O(dt^(-d)|log dt|) or even to O(dt^(-d)).QC 20121116
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Suwantong, Rata. "New Structure for Moving Horizon Estimators. Application to Space Debris Tracking during the Atmospheric Re-entries." Thesis, Supélec, 2014. http://www.theses.fr/2014SUPL0023/document.
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L’estimation de trajectoires de débris spatiaux pendant la rentrée atmosphérique est un défi majeur pour les prochaines années, renforcé par plusieurs projets liés à l'enlèvement de débris établis par plusieurs agences spatiales. Cependant, ce problème s’avère complexe du fait des erreurs de modèle et des difficultés d’initialisation des algorithmes d’estimation induites par une mauvaise connaissance de la dynamique des débris suite à leur désintégration pendant la phase de rentrée atmosphérique. Tout estimateur choisi doit donc être robuste vis-à-vis de ces facteurs. L’estimateur à horizon glissant (MHE) est reconnu dans la littérature pour être robuste vis-à-vis d’erreurs de modèle et de mauvaise initialisation, et les travaux de thèse ont montré qu’il était adapté en termes de performances à la problématique de l’estimation des débris en phase de rentrée. En revanche, il se fonde sur une stratégie d’optimisation qui requiert de fait un temps de calcul important. Pour pallier ce problème, une nouvelle structure d’estimation à horizon glissant a été développée, impliquant un temps de calcul faible nécessaire à l’application envisagée. Cette stratégie, appelée « estimateur à horizon glissant avec pré-estimation (MHE-PE)», prend en compte les erreurs de modèle via un estimateur auxiliaire, plutôt que de chercher à obtenir les estimées du bruit d’état sur l’horizon d’estimation, comme le fait la structure de l’estimateur MHE standard. Un théorème garantissant la stabilité de la dynamique de l’erreur d’estimation du MHE-PE a par ailleurs été proposé. Enfin, les performances de cette structure dans le cadre de l’estimation en trois dimensions des trajectoires de débris pendant la phase de rentrée se sont avérées meilleures que celles observées avec des estimateurs classiques. En particulier, sans dégrader la précision et la convergence de l’estimation, l’estimateur MHE-PE requiert moins de temps de calcul du fait du nombre réduit de paramètres à optimiserSpace debris tracking during atmospheric re-entries will be a crucial challenge in the coming years, emphasized through many projects on space debris mitigation established by space agencies worldwide. However, this problem appears to be complex, due to model errors and difficulties to properly initialize the estimation algorithms, as a result of unknown dynamics of the debris and their disintegrations during the re-entries. A-to-be used estimator for this problem must be robust against these factors. The Moving Horizon Estimator (MHE) is known in the literature to be robust to model errors and bad initialization, and the PhD work has proved its ability to satisfy performances required by the debris tracking during the re-entries. However, its optimization-based framework induces a large computation time. To overcome this, a new MHE structure which requires smaller computation time than the classical MHE has been developed. This strategy, so-called “Moving Horizon Estimator with Pre-Estimation (MHE-PE)” takes into account model errors by using an auxiliary estimator rather than by searching for estimates of the process noise sequence over the horizon as in the classical strategy. A theorem which guarantees the stability of the dynamics of the estimation errors of the MHE-PE has also been proposed. Finally, performances of this structure in the context of 3D space debris tracking during the re-entries have been shown to be better than those obtained with classical estimators including the MHE. In particular, without degrading accuracy of the estimates and convergence of the estimator, the MHE-PE estimator requires smaller computation time than the MHE thanks to its small number of optimization variables
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Nguyen, Tam Nguyen Thuc. "Laser beacon tracking for free-space optical communication on small-satellite platforms in low-earth orbit." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101446.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015.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 91-94).
Free-space optical (FSO) communication, or laser communication, is capable of providing high-rate communication links, meeting the growing downlink demand of space missions, including those on small-satellite platforms. FSO communication takes advantage of the high-gain nature of narrow laser beams to achieve higher link efficiency than traditional radio-frequency systems. In order for a FSO link to be established and maintained, the spacecraft's attitude determination and control system needs to provide accurate pointing at the optical ground station. However, small satellites, such as CubeSats, have limited ground-tracking capabilities with existing attitude sensors. Miniaturized laser beacon tracking system, on the other hand, has the potential to provide precise ground-based attitude knowledge, enabling laser communication to be accomplished on small-satellite platforms. This thesis details the development of a CubeSat-sized laser beacon camera capable of achieving a sub-milliradian attitude knowledge accuracy with low fade probability during various sky conditions, sufficient to support a high-rate FSO communication link on a CubeSat platform on low-Earth orbit. The high-level Nanosatellite Optical Downlink Experiment (NODE) system architecture, the beacon camera conceptual design as well as prototype development are presented in detail. An end-to-end beacon simulation was constructed to validate the attitude sensing performance of the module under expected atmospheric turbulence and sky brightness conditions. The simulation results show a high-accuracy attitude sensing performance and low fade probability, capable of supporting NODE's laser links.
by Tam Nguyen Thuc Nguyen.
S.M.
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Conrad, Ross Aaron. "Impact of the boundary layer on pointing and tracking in airborne free-space laser communication links." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44929.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes vita.
Includes bibliographical references (p. 117-118).
Free-space laser communication is a developing technology with enormous potential to revolutionize the way people communicate across the globe. Of specific interest are air-to-space lasercom links. Such a link experiences atmospheric scintillation, platform jitter, and boundary layer turbulence. This research investigated the tracking challenge using a focal plane array sensor with centroid and peak tracking algorithms. Also investigated was the use of a deformable mirror to recreate optical phase distortions from boundary layer turbulence. Experiments were conducted with realistic channel effects for multiple look angles between a subsonic aircraft at 29 kft and geosynchronous satellite. Performance was determined by power delivered to an optical fiber. The results show that the two tracking algorithms can differ by up to one decibel of fiber power, with centroid tracking generally performing best. Conclusions are highly dependent on aircraft and spacecraft parameters but point towards centroid tracking for maximizing received power. Keywords: Lasercom, FPA Tracking, Boundary Layer Disturbances, Deformable Mirror.
by Ross Aaron Conrad.
S.M.
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Maples, Bruce W., and Keith A. Fix. "An IF Sampling Digital Receiver Implementation for Space-based Command and Telemetry Applications." International Foundation for Telemetering, 2002. http://hdl.handle.net/10150/607493.
Full textAbstract:
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, CaliforniaThis paper describes an approach to the implementation of an IF sampling digital receiver for low data rate command and telemetry applications in the NASA Goddard Spaceflight Tracking and Data Network (STDN) and Air Force Space-Ground Link System (SGLS). The digital design is targeted for an FPGA-based implementation and was written entirely in VHDL. Several size and clock reduction techniques are described which were utilized due to limited gate-array resources and power. The system-level design architecture is described followed by a discussion of algorithms and performance of critical stages in the receiver chain. Bit error performance of the prototype receiver is also presented. Finally, although this design is specifically targeted for a narrowband command and telemetry application, the methodology forms the basis of a configurable receiver for higher data rate applications.
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Burkes, Darryl A. "GROUND SUPPORT FOR THE SPACE-BASED RANGE FLIGHT DEMONSTRATION 2." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604565.
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ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaThe primary objective of the NASA Space-Based Range Demonstration and Certification program was to develop and demonstrate space-based range capabilities. The Flight Demonstration 2 flights at NASA Dryden Flight Research Center were conducted to support Range Safety (commanding and position reporting) and high-rate (5 Mbps) Range User (video and data) requirements. Required ground support infrastructure included a flight termination system computer, the ground-data distribution network to send range safety commands and receive range safety and range user telemetry data and video, and the ground processing systems at the Dryden Mission Control Center to process range safety and range user telemetry data and video.
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Petit, Antoine. "Robust visual detection and tracking of complex objects : applications to space autonomous rendez-vous and proximity operations." Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00931604.
Full textAbstract:
In this thesis, we address the issue of fully localizing a known object through computer vision, using a monocular camera, what is a central problem in robotics. A particular attention is here paid on space robotics applications, with the aims of providing a unified visual localization system for autonomous navigation purposes for space rendezvous and proximity operations. Two main challenges of the problem are tackled: initially detecting the targeted object and then tracking it frame-by-frame, providing the complete pose between the camera and the object, knowing the 3D CAD model of the object. For detection, the pose estimation process is based on the segmentation of the moving object and on an efficient probabilistic edge-based matching and alignment procedure of a set of synthetic views of the object with a sequence of initial images. For the tracking phase, pose estimation is handled through a 3D model-based tracking algorithm, for which we propose three different types of visual features, pertinently representing the object with its edges, its silhouette and with a set of interest points. The reliability of the localization process is evaluated by propagating the uncertainty from the errors of the visual features. This uncertainty besides feeds a linear Kalman filter on the camera velocity parameters. Qualitative and quantitative experiments have been performed on various synthetic and real data, with challenging imaging conditions, showing the efficiency and the benefits of the different contributions, and their compliance with space rendezvous applications.
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Louw, Illka. "From designer through space to spectator : tracking an imaginative exchage between the actants of a scenographic event." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/11200.
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Includes bibliographical references.The aim of this enquiry is to deepen the understanding of the author's practice as theatre designer, scenographer and visual dramaturge in a postdramatic milieu. This study creates a theoretical frame for a research-led performance that is especially dependent on the release of 'active energies of imagination' (Lehmann, 2006:16). The performance will take the form of a scenographic event,which does not depend on 'the principles of narration and figuration' (Lehmann, 2006:18). Instead it relies on a 'visual dramaturgy ' in which just as in front of a painting, activates the dynamic capacity of the gaze to produce processes, combinations and rhythms on the basis of the data provided by the stage' (Lehmann, 2006:157). The study proposes that the release of 'active energies of imagination' (2006:16) extends beyond the space of the live event, tracking its origin to the interaction between the designer and the materials of her art.
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Kujiroaoka, Scott R., Russell G. Fielder, and Alvia D. Sandberg. "Current Status of Adding GPS Tracking Capability to a Missile Telemetry Section." International Foundation for Telemetering, 2008. http://hdl.handle.net/10150/606153.
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ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, CaliforniaPast presented papers have discussed the integration efforts of incorporating Central Test & Evaluation Investment Program (CTEIP) sponsored Joint Advanced Missile Instrumentation (JAMI) components (namely the JAMI TSPI Unit-JTU), Commercial off the Shelf (COTS) parts (e.g. ARTM Tier I SO-QPSK Transmitter, Encryptor and Thermal Battery), and in-house developed devices (such as PCM Encoder and Dual Band Antenna) into a five-inch diameter Missile Telemetry (TM) Section. A prototype of this TM Section has been built up and integrated into an All Up Round (AUR) Missile and twice flown as a Captive Carried Test Missile (CTM) on an F/A-18 jet with great success. This TM Section is in the process of undergoing flight qualification testing (including environmental and electro-magnetic interference-EMI tests). After which it will be ready for mass production. This paper will detail these current efforts. In addition, the effort to upgrade some Navy and Air Force Test Ranges (with JAMI Ground Stations and Decommutators/Demodulators) to track and gather data from this Missile containing the new TM section will be discussed. Future plans to incorporate Flight Termination System (FTS) capabilities into the TM section will be covered as well.
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Strausz, Laszlo. "Traveling through Space: Stylistic Progression and Camera Movement." unrestricted, 2007. http://etd.gsu.edu/theses/available/etd-04202007-122230/.
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Thesis (Ph. D.)--Georgia State University, 2007.Title from file title page. Greg M. Smith, committee chair; Charlie Keil, Ted Friedman, Kathy Fuller-Seeley, Angelo Restivo, committee members. Electronic text (310 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Oct. 17, 2007. Includes bibliographical references (p. 276-283).
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Arredal, Martin. "Eye Tracking’s Impact on Player Performance and Experience in a 2D Space Shooter Video Game." Thesis, Blekinge Tekniska Högskola, Institutionen för datavetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-17823.
Full textAbstract:
Background. Although a growing market, most of the commercially available gamestoday that features eye tracking support is rendered in a 3D perspective. Games ren-dered in 2D have seen little support for eye trackers from developers. By comparing the differences in player performance and experience between an eye tracker and acomputer mouse when playing a classic 2D genre: space shooter, this thesis aim tomake an argument for the implementation of eye tracking in 2D video games. Objectives. Create a 2D space shooter video game where movement will be handledthrough a keyboard but the input method for aiming will alter between a computermouse and an eye tracker. Methods. Using a Tobii EyeX eye tracker, an experiment was conducted with fif-teen participants. To measure their performance, three variables was used: accuracy,completion time and collisions. The participants played two modes of a 2D spaceshooter video game in a controlled environment. Depending on which mode wasplayed, the input method for aiming was either an eye tracker or a computer mouse.The movement was handled using a keyboard for both modes. When the modes hadbeen completed, a questionnaire was presented where the participants would ratetheir experience playing the game with each input method. Results. The computer mouse had a better performance in two out of three per-formance variables. On average the computer mouse had a better accuracy andcompletion time but more collisions. However, the data gathered from the question-naire shows that the participants had on average a better experience when playingwith an eye tracker Conclusions. The results from the experiment shows a better performance for par-ticipants using the computer mouse, but participants felt more immersed with the eyetracker and giving it a better score on all experience categories. With these results,this study hope to encourage developers to implement eye tracking as an interactionmethod for 2D video games. However, future work is necessary to determine if theexperience and performance increase or decrease as the playtime gets longer.
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Harwood, Peter, Christopher Wilson, Arthur Sullivan, and Eugene Augustin. "LOW COST, HIGHLY TRANSPORTABLE, TELEMETRY TRACKING SYSTEM FEATURING THE AUGUSTINE/SULLIVAN DISTRIBUTION AND POLARIZATION, FREQUENCY AND SPACE DIVERSITY." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/608364.
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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThe tracking system is part of a telemetry ground station being developed for the UK Ministry of Defence. The design objective is a self-contained transportable system for field use in a vehicle or workshop environment, so that the system components are required to be man portable. Comprehensive facilities are required for the reception, display and analysis of telemetry data from a remote 1430-1450MHz airborne source at ranges of up to 205km. Since tracking over water is a prime requirement the system must accommodate severe multipath fading. A detailed analysis of the link budget indicates that there is a major conflict between cost, portability, antenna size and the receiver complexity required to achieve a satisfactory performance margin. A baseline system is analysed using a four foot antenna. Methods for improving the performance are then considered including polarisation, frequency and space diversity coupled with alternative antenna types and configurations. The optimum solution utilises two six foot diameter shaped beam single axis antennas of unique design in conjunction with a receiving system which economically combines the elements of polarisation, frequency and space diversity.
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Cardona, Tommaso. "Tracking, photometry and spectroscopy of space debris: the Malindi, Loiano, Las Campanas and Cerro Tololo observation campaign results." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5905/.
Full textAbstract:
The main purpose of my thesis has been the analysis of the space debris environment and their characterization through optical measurements. In particular I had the opportunity to contribute to the Italian Space Agency activities in space debris optical observation campaign and I cooperated directly with NASA Orbital Debris Program Office by working at the Astronomy Department of the University of Michigan for six months.