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Dissertations / Theses on the topic 'Attitude determination'
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Bejeryd, Johan. "GPS-based attitude determination." Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11029.
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<p>Inertial sensors and magnetometers are often used for attitude determination of moving platforms. This thesis treats an alternative method; GPS-based attitude determination. By using several GPS-antennas, and with carrier phase measurements determining the relative distance between them, the attitude can be calculated.</p><p>Algorithms have been implemented in Matlab and tested on real data. Two commercial GPS-based attitude determination systems have also been tested on a mobile platform and compared to a navigation grade Inertial Navigation System (INS). The results from the tests show that GPS-based attitude determination works well in open areas, but would require support from additional sensors in urban and forest environments.</p>
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Thorstensson, Erika. "GPS based attitude determination." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-94447.
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This paper is the result of a masters thesis performed at Linköping University for Saab Bofors Dynamics in Linköping, Sweden. Attitude is defined as the orientation of a coordinate frame in reference to another coordinate frame. This is often referred to as three consecutive rotations, called roll, pitch and yaw (or heading). Attitude determination is generally performed using inertial navigation systems composed of gyros and accelerometers. These systems are highly accurate but are very expensive and experience a drift when used for a long period of time. The global positioning system, or GPS, was developed by the US military to determine a user’s position, velocity and time. These parameters can all be determined by performing measurements on the GPS satellite signal code that is modulated onto the GPS satellite signal carrier. But the GPS signal can also be use to determine attitude by performing carrier measurements for two or more GPS antennas. When determining the relative position between two antennas, by measuring the phase difference between them, information of the baseline is attained. The calculated baseline will be in a local navigation frame. By rotating it to the known body frame, a rotation matrix known as a direction coordinate matrix, or DCM, will be attained. From this rotation matrix, only two of the three attitude angles can be calculated, since the third rotation is about the baseline’s own axis. Using three or more antennas (two or more baselines), all three attitude angles can be determined from the DCM. This thesis work included development of a hardware platform carrying four NovAtel Superstar II GPS receivers. The platform enables serial communications between the receivers and a PC, as well as providing the supply for the receivers and antennas. The attitude determination algorithm was written and tested using a test platform mounted onto a car. The result shows a one degree deviation from an INS reference system in heading and pitch during both static and dynamic tests. The roll angle was not measured during the test drives because only one baseline was locked. The GPS based attitude determination system performed well when the baselines were locked, but it requires some improvements for full functionality.
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Hollensteiner, Erwin. "Drilling attitude determination and control." Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555799.
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This thesis is concerned with the development of a new robust and efficient real time signal processing algorithm for a rotating strapdown inertial navigation system (INS). Although the signal processing in INS is dominated by the Kalman filter algorithm, often this algorithm is not feasible for small microcontroller or digital signal processor (DSP) applications. This thesis develops a new fixed point DSP algorithm for cal- culating the optimal estimate of orientation of the INS. In this thesis Kalman filter algorithms in INS are discussed. A filter algorithm for a rotating inertial navigation system is developed. The discussed navigation system is part of an oil drilling tool. The theoretical work is verified by a set of experiments and field tests. The experi- mental results have shown that the required attitude measurement accuracy can be achieved. It has been shown that it is possible to control the attitude for a directional drilling tool.
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Jacquemont, Christian M. (Christian Marie) 1972. "Aircraft attitude determination using robust estimation." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10202.
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Arrigo, Jeanette Fay Freauf. "Improved VLSI architecture for attitude determination computations." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3195257.
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Thesis (Ph. D.)--University of California, San Diego, 2006.<br>Title from first page of PDF file (viewed February 28, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Kaplan, Ceren. "Leo Satellites: Attitude Determination And Control Components." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607189/index.pdf.
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In this thesis, application of linear control methods to control the attitude of a Low-Earth Orbit satellite is studied. Attitude control subsystem is first introduced by explaining attitude determination and control components in detail. Satellite dynamic equations are derived and linearized for controller design. Linear controller and linear quadratic regulator are chosen as controllers for attitude control. The actuators used for control are reaction wheels and magnetic torquers. MATLAB-SIMULINK program is used in order to simulate satellite dynamical model (actual nonlinear model) and controller model. In simulations, the satellite parameters are selected to be similar to the actual BILSAT-1 satellite parameters. In conclusion, simulations obtained from different linear control methods are compared within themselves and with nonlinear control methods, at the same time with that obtained from BILSAT-1 satellite log data.
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Thorstenson, Stefan. "IMU-based enhancement of GPS attitude determination." Thesis, Linköpings universitet, Reglerteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-79930.
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GPS carrier-phase measurements from two GPS antennas can be used to calculate the heading of the baseline that can be drawn between the two antennas. An integer ambiguity problem has to be solved, and the system is called GPS attitude determination (GPSAD). This way of calculating the heading is cheaper than the traditional ways to do it, but it requires GPS reception. This thesis investigates how and if an inertial measurement unit (IMU) can support the GPS-based system, and divides the question into four problems: heading estimate during GPS outages, reducing the ambiguity search space, cycle slip detection and multipath mitigation. A relatively cheap IMU was used, and an extended Kalman filter (EKF) was implemented to continue to supply heading estimates during GPS outages with a drift less than 1/min in the studied case. When the GPS reception is good enough after an outage, the EKF supplies the GPSAD with an interval of the heading estimate to reduce the ambiguity search space. It has been investigated how to detect and deal with cycle slips, and the conclusion is that an IMU can help with detecting the slips, although nothing has been implemented. Multipath is still an issue, but some approaches to reduce the effect are suggested. The overall performance of the system is greatly increased with the help of an IMU. Performance increasing work can still be done, especially for the cooperation between the GPSAD and the EKF.
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De, Ruiter Anton. "Nonlinear state-estimation for spacecraft attitude determination." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62888.pdf.
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Dai, Zhen [Verfasser]. "On GPS based attitude determination / Zhen Dai." Siegen : Universitätsbibliothek der Universität Siegen, 2013. http://d-nb.info/1034425951/34.
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Scaccia, Milena. "Numerical algorithms for attitude determination using GPS." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103616.
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Attitude determination involves the estimation of the orientation of a body (usually aircraft or satellite) with respect to a known frame of reference. It has important applicationsin areas spanning navigation and communication. There exist two main approaches for determining attitude using the Global Positioning System (GPS): (1) algorithms which determine attitude via baseline estimates in two frames, and (2) algorithms which solve for attitude by incorporating the attitude parameters directly into the state. For each approach, we propose an algorithm which aims to determine attitude in an efficient and numerically reliable fashion. We present numerical simulations demonstrating the performance of our algorithms and provide a comparison evaluating which approach is better - a result which is not presently clearly documented in the literature.<br>La détermination de l'attitude est l'estimation de l'orientation dans l'espace d'un véhicule ou d'un satellite par rapport à un repère de référence. Ils existent des applications importantes qui exigent la connaissance de l'attitude, particulièrement dans les domaines de navigation et de communication. La détermination de l'attitude à l'aide de GPS peut être obtenue a partir de deux approches: (1) en déterminant la rotation en utilisant des estimées de lignes de base de deux repères, ou (2) en utilisant des mesures de GPS pour déterminer les paramètres d'attitude directement. Pour chaque approche, on propose un algorithme à but de déterminer l'attitude de manière efficace et numériquement fiable. On présente des simulations démontrant la performance de nos algorithmes. On présente aussi une comparaison évaluant quelle serait la meilleure approche - un résultat qui n'est pas actuellement clairement documenté dans la littérature.
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Gupta, Rishi Vijay. "A compressive sensing algorithm for attitude determination." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66422.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 29-30).<br>We propose a framework for compressive sensing of images with local distinguishable objects, such as stars, and apply it to solve a problem in celestial navigation. Specifically, let x [epsilon] RN be an N-pixel image, consisting of a small number of local distinguishable objects plus noise. Our goal is to design an m x N measurement matrix A with m << N, such that we can recover an approximation to x from the measurements Ax. We construct a matrix A and recovery algorithm with the following properties: (i) if there are k objects, the number of measurements m is O((klog N)/(log k)), undercutting the best known bound of O(klog(N/k)) (ii) the matrix A is ultra-sparse, which is important when the signal is weak relative to the noise, and (iii) the recovery algorithm is empirically fast and runs in time sub-linear in N. We also present a comprehensive study of the application of our algorithm to attitude determination, or finding one's orientation in space. Spacecraft typically use cameras to acquire an image of the sky, and then identify stars in the image to compute their orientation. Taking pictures is very expensive for small spacecraft, since camera sensors use a lot of power. Our algorithm optically compresses the image before it reaches the camera's array of pixels, reducing the number of sensors that are required.<br>by Rishi Vijay Gupta.<br>M.Eng.
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Bylund, Oscar. "Attitude Determination and Control of a Cubesat." Thesis, KTH, Rymdteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231376.
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This report describes the feasibility of attitude determination and control of the student satellite MIST. It investigates the stability and controllability of the satellite system, it covers attitude determination based on magnetometer and sun sensor measurements available and finally compares two controllers and the resulting pointing accuracy of the satellite. The study shows that the pointing requirements can be met under nominal circumstances.<br>I denna rapport utreds hur noggrannt en studentsatellits attityd kan uppskattas och kontrolleras. Sensorerna och aktuatorerna består av en magnetometer, tre magnetiska spolar och sex solsensorer. Mätningarna filtreras och används i två olika regleralgoritmer, följt av en jämförelse mellan resultaten av de båda metoderna. Rapporten visar att satellitens noggrannhetskrav på attityden kan uppfyllas under normala förhållanden.
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Sabala, Ryan J. "Satellite Attitude Determination Using Laser Communication Systems." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1218636153.
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Bowen, John Arthur. "On-Board Orbit Determination and 3-Axis Attitude Determination for Picosatellite Applications." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/131.
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This thesis outlines an orbit determination and 3-axis attitude determination system for use on orbit as applicable to 1U CubeSats and other picosatellites. The constraints imposed by the CubeSat form factor led to the need for a simple configuration and relaxed accuracy requirements. To design a system within the tight mass, volume, and power constraints inherent to CubeSats, a balance between hardware complexity, software complexity and accuracy is sought. The proposed solution consists of a simple orbit propagator, magnetometers with a magnetic field look-up table, Sun sensors with an analytic Sun direction model, and the TRIAD method to combine vector observations into attitude information. The orbit propagator is a simple model of a circular trajectory with several frequently updated parameters and can provide orbital position data with average and maximum errors—when compared to SGP4—of less than 3.7km and 10.7km for 14 days. The magnetic field look up table provides useful information from a small memory footprint; only 480 data points provide a mean error of approximately 0.2° and a maximum error of approximately 2°—when compared to the IGRF model. The Sun’s direction is modeled, and as expected, can be modeled simply and accurately. Combining the magnetic field and Sun direction models with inaccurate sensors and the TRIAD method results in useful attitude information from a very simple system. A system with Sun sensor error standard deviation of 1° and magnetometer error standard deviation of 5° yields results with average error of only 2.74°, and 99% of the errors in this case are less than approximately 13°. The system outlined provides crude attitude determination with software and hardware requirements that are well within the capabilities of current 1U CubeSats—something that many other systems, such as Kalman filters or star trackers, cannot do. It also provides an excellent starting point for future ADCS systems, which will significantly increase the ability of CubeSats.
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Rohde, Jan. "Kalman filter for attitude determination of student satellite." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8823.
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<p>In the autumn of 2006 a satellite project was started at NTNU. The goal of the project is two-folded, first it seeks to create more interest and expertise around the field of space technology, secondly to create a satellite platform which can be modified and equipped with different payloads to perform selected tasks in a Low Earth Orbit. For a satellite to be able to complete missions involving sensory and imaging, an attitude determination and control system is needed to give the satellite a stable attitude. In order to create a good attitude control system, a Gauss-Newton improved extended Kalman filter is used together with reference models to supply the controller with estimates of both satellite angular velocity and orientation. This report focuses on the Attitude Determination System, ADS, realized by implementing the improved extended Kalman filter on a microcontroller. The challenge is to create an estimator that will provide the control system with adequate estimates without requiring to much computational power, as this is a limiting factor on board a micro satellite. The need for good computational power comes from the multidimensional matrix mathematical operations performed on float numbers. Based on previous work, an improved Extended Kalman filter has been developed and implemented on a microcontroller for further testing. A new filter, the Unscented Kalman Filter has also been explored but not implemented.</p>
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Schoonwinkel, Johannes. "Attitude determination and control system of a nanosatellite." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/708.
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Bamber, D. C. "Attitude determination through registration of earth observational imagery." Thesis, University of Surrey, 2008. http://epubs.surrey.ac.uk/770396/.
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With the increasing resolution of Earth observational sensors there is an increasing need for reliable, frequent and accurate attitude knowledge. Typically, high accuracy attitude systems incur large mass and costs, limiting the potential missions to which small or inexpensive satellites may apply. A neea tnererore exists tor low-mass, low-cost attitude systems capable or obtaining high accuracy attitude telemetry, especially during image capture and onboard small satellites. Towards such ends, this research investigates the potential use of a narrow stereo angle between pushbroom sensors for determining the attitude of a spacecraft.
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Maguire, Sean Thomas George. "Attitude determination using low frequency radio polarisation measurements." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708927.
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Zhou, Jiewei. "Attitude Determination and Control of the CubeSat MIST." Thesis, KTH, Farkost och flyg, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203284.
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The ADCS concept in MIST reects the limitations of the CubeSat in terms of space, power and onboard computer computational capability. The control is constrained to the use of only magnetic torquers and the determination to magnetometers and Sun sensors in spite of the the under-actuation and underdetermination during eclipses. Usually small satellites with a similar ADCS and demanding requirements fail, therefore MIST would be a design reference for this kind of concept in the case it succeeds. The objectives of this thesis work are the feasibility assessment of the concept to meet the nominal requirements in MIST and the consideration of alternatives. Firstly, the importance of gravitational stabilization and di erent congurations for the inertial properties are analyzed based on the linear stability regions for nadir pointing spacecraft. Besides, extended stability regions are derived for the case when a momentum wheel is used to consider alternative options for passive stabilization in terms of the inertial properties. Then a controller based on the Asymptotic Periodic Linear Quadratic Regulation (AP LQR) theory, the currently most extended and e ective for pure magnetic control in small satellites, is assessed. Also a Liner Quadratic Regulator design by means of numerical optimization methods, which has not been used in any real mission, is considered and its performances compared with the AP LQR. Regarding attitude determination a Linear Kalman Filter is designed using the AP LQR theory. Finally, a robustness analysis is conducted via Monte Carlo simulations for those control and determination strategies.<br>Systemet for attitydstyrning och -bestamning i nanosatelliten MIST reekterar sma satelliters begransningarna i utrymme, elkraft och omborddatorkapacitet. Regleringen ar begransad till styrning med magnetspolar som genererar kraftmoment. For attitydbestamningen anvands magnetometrar och solsensorer trots under-manovrering och -bestamning vid solformorkelse. Vanligtvis misslyckas sma satelliter med liknande reglersystem och hoga krav, sa om MIST lyckas skulle den bli ett referenskoncept. Malen med detta examensarbete ar att utfora en genomforbarhetsstudie av ett reglerkoncept for att mota de nominella kraven for MIST samt undersoka av alternativa reglersystem. E ekten av gravitationsstabilisering och olika masstroghetskongurationer har analyserats med hjalp av linjariserade stabilitetsregioner for en nadirpekande satellit. Stabilitetsregionerna forstoras da ett roterande hjul infors i ett alternativt stabiliseringskoncept eftersom det roterande hjulet paverkar de e ektiva masstroghetsmomentet. Regleringsalgoritmen som utvarderats i detta arbete ar baserad pa teorin om Asymptotisk Periodisk Linjar Kvadratisk Regulering (AP LKR), den som ar mest anvand samt e ektiv for ren magnetisk styrning av sma satelliter. En utformning av ett koncept baserat pa Linjar Kvadratisk Reglering med numerisk optimering, vilket inte tidigare verkar anvants for ett riktigt rymduppdrag, har undersokts och jamforts med AP LKR-regleringen. Nar det galler attitydbestamningen sa har ett linjart Kalmanlter utformats for AP LKR-regleringen. Slutligen sa har en robusthetsanalys gjorts genom Monte Carlo-simuleringar for styrnings- och bestamningsstrategierna.<br>El concepto para el ADCS en MIST reeja las limitaciones de los CubeSats en cuanto a espacio, potencia y capacidad computacional del ordenador a bordo. El control esta restringido al uso de solo magnetopares y la determinacion a magnetometros y sensores de Sol a pesar de la imposibilidad de actuacion segun todos los ejes y el conocimiento incompleto en actitud durante eclipses. Normalmente peque~nos satelites con un ADCS similar y exigentes requisitos fallan, por la tanto MIST sera una referencia de dise~no para este tipo de concepto en el caso de que tenga exito. Los objetivos de este trabajo n de master son la evaluacion de la viabilidad del concepto para cumplir los requisitos nominales en MIST y la consideracion de alternativas. Primero, la importancia de la estabilizacion gravitacional y diferentes conguraciones para las propiedades masicas son analizadas en base a las regiones de estabilidad lineales para vehculos espaciales apuntando segun nadir. Ademas, regiones de estabilidad extendidas son deducidas para el caso en el que una rueda de momento es usada con el n de considerar opciones alternativas de estabilizacion pasiva en terminos de las propiedades masicas. Despues un controlador basado en la teora del Asymptotic Periodic Linear Quadratic Regulation, el actualmente mas extendido y efectivo para control magnetico puro en peque~nos satelites, es evaluado. Tambien un dise~no de LQR por medio de metodos de optimizacion numerica, el cual no ha sido usado en ninguna mision real, es considerado y sus prestaciones comparadas con el AP LQR. En relacion a la determinacion de actitud un Linear Kalman Filter es dise~nado usando la teora del AP LQR. Finalmente, un analisis de robustez es llevado a cabo a traves de simulaciones de Monte Carlo para esas estrategias de control y determinacion.
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Dever, Christopher W. (Christopher Walden) 1972. "Vehicle model-based filtering for spacecraft attitude determination." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47801.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.<br>Includes bibliographical references (p. 166-170) and index.<br>This thesis investigates the use of vehicle model-based filtering for spacecraft attitude determination. Whereas traditional navigation filters typically rely only on the kinematic relations between body rate and attitude in their filter designs, the state estimator presented here expands the plant model to include rigid body effects and disturbance torques. When rate sensing gyroscope measurement error components are large, as is anticipated in the new generation of micromechanical inertial sensors, the model-based approach provides superior performance to the standard kinematic designs. The estimation performance gains, which include enhanced attitude tracking of several tenths of a degree and closed-loop control stabilization, are most apparent when external attitude data becomes sparse. Even if the gyroscope measurement quality were to improve, for some satellite missions the possibility of an external measurement outage still necessitates vehicle dynamic modeling for greater gyro bias observability. The thesis also gives insight into robustness measures to compensate for model uncertainty, disturbance torque estimation, and GPS multipath error mitigation.<br>by Christopher W. Dever.<br>S.M.
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Rangel, Enger Eric. "Spacecraft attitude determination methods in an educational context." Thesis, KTH, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265612.
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This work has as an objective to structure the content of a course on Attitude determination methods, part of an Aerospace Engineering Master program. A selection of books, papers, theses, web sites and films was reviewed to identify the most relevant topics within the areas of Static and Dynamic Attitude Determination and the ways to present them in a educational context. Theory is presented in a simplified way and examples were gathered to illustrate the theoretical part. Finally, a discussion is carried out on the main learning goals and challenges, required time for instruction and exercises and suggestion for a grading system.<br>Detta arbete har som mål att strukturera innehållet i en kurs om Attitydbestämningsmetoder inom flyg- och rymdteknikmastersprogram. Ett urval av böcker, artiklar, avhandlingar, webbsidor och filmer granskades för att identifiera de mest relevanta ämnena inom statisk och dynamisk attitydbestämning och de olika sätten att presentera dem i ett utbildningssammanhang. Teorin presenteras på ett förenklat sätt och några exemplar visas för att illustrera den teoretiska delen. Avslutningsvis, diskuteras de huvudsakliga lärandemålen, nödvändig handledning och övningstid, samt betygsättning.
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Hammer, Strand Mads Peter. "Phase detection for attitude determination In quadrotors or 'drones'." Thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-29677.
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This thesis aims to prove that it is possible to use phase difference detection as a means of determining an objects attitude in relation to a signal source. A correlation between orientation and phase-detector output is proved, and it is concluded that with further work on algorithms and signal filtering, an attitude determination system could be made. As Quadrotors or ’drones’ are controlled by a system that could benefit by another reference system, accuracy of the phase-detector system is compared with the navigation systems currently used in drones.
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Travis, Henry D. "Attitude determination using Star Tracker Data with Kalman filters." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA401577.
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Thesis (M.S. in Electrical Engineeirng)--Naval Postgraduate School, December 2001.<br>"December 2001". Thesis advisor(s): Titus, Harold A. Includes bibliographical references (p. 51-53). Also available online.
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Tønne, Karianne Knutsen. "Stability Analysis of EKF - based Attitude Determination and Control." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8720.
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<p>This thesis is a part of the SSETI (Student Space Exploration Technology Initiative) project, where students from several universities around Europe work together with the European Space Agency (ESA) with designing, building, testing and launching an Earth-Moon satellite orbiter (European Student Moon Orbiter (ESMO). A satellite model with reaction wheels placed in tetrahedron was deduced in a preliminary study together with an extended Kalman filter to estimate the attitude from star measurements. The stability and convergence properties of this system are studied in this thesis. Previous studies on the convergence of extended Kalman filter are presented and a proof of exponentially convergence of a system with extended Kalman filter is given and used to prove that ESMO with the extended Kalman filter converges exponentially. The most recent work and different methods to apply a nonlinear separation principle is presented. Three feedback controllers with proof of global asymptotic stability (GAS) is then introduced and implemented on ESMO. Based upon the global asymptotic stability of the feedback controllers, and the proof that the extended Kalman filter works as an exponentially observer, a nonlinear separation principle is deduced. The closed loop system can then be stated globally asymptotically stable based upon the deduced separation principle. The closed loop with the three different controllers is then simulated in Simulink for varying gains and different reference steps. The three controllers show stable characteristic as the theory implies. The robust controller shows best tracking and estimation properties, it is very accurate, simple, robust and adaptable to environmentally changes, and is therefore proposed as the most suitable controller for ESMO.</p>
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Waarum, Ivar-Kristian. "Stability Analysis of Nonlinear Attitude Determination and Control Systems." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8729.
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<p>This report describes the modelling and performance of an attitude determination and control system (ADCS) for a small satellite in lunar orbit. The focus is on stability analyses of each of the components in the system, and of the system as a whole. In connection to this, the separation principle for nonlinear systems is investigated. Central background information is presented, covering necessary rigid body dynamics and stability properties. Three different controller types are analysed and compared herein, namely a model-dependent linearizing controller, a robust controller and a standard PD-controller. An observer is chosen based on earlier work, but some detail modifications are made to its structure. A state-space model of the satellite and environment is derived and implemented in Matlab, along with the observer and controllers. The observer and all three controllers are shown to be stable with Lyapunov analysis. The total ADCS including the observer is shown to have a cascaded structure, on which theory of nonlinear separation principles is used to establish stability properties of the total system. Finally, the ADCS is put to simulation tests imitating real-life scenarios and the performance of the different controllers are compared. The PD-controller shows the best performance, both in speed of convergence and robustness to model errors. While not completely satisfactory, the results give a basis on which to perform further work.</p>
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Rinnan, Toril Bye. "Development and Comparison of Estimation Methods for Attitude Determination." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18421.
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The NTNU Test Satellite (NUTS) project, is part of the Norwegian Student Satellite programANSAT. The goal of the project is to design and launch a double CubeSat by the endof 2014. During earlier satellite projects at NTNU, solid work on design of the attitudedetermination and control for a small satellite has been done.One of the considered estimation methods for the attitude determination is the extendedquaternion estimation method (EQUEST). Further development and testing of themethod is described in this thesis. In addition to the new EQUEST method, a nonlinearobserver has been implemented and tested. The simulation results for the two methods arecompared in order to find the attitude estimation method best suited for the NUTS satellite.The new EQUEST method has several advantages over the more common Kalmanfiltering for use in small CubeSats. It is less computationally costly, and has a fast startupand settling time. Magnetorquers, which affect the local magnetic field, are used asactuators for the satellite. This makes a fast algorithm preferable, since the attitude estimationand the attitude control should be performed separately. The nonlinear observer isslower than the EQUEST method, but it can guarantee global exponential stability and itis less vulnerable to disturbances. It is therefore introduced as an alternative solution forthe attitude determination problem.The original EQUEST method builds upon the QUEST method which has been extendedto include non-vectorized terms for gyroscope measurements and attitude predictionin the method’s cost function. In these terms, subtractions between the estimated andmeasured quaternions are used. The result is not entirely mathematically correct, eventhough previous testing of the method has been successful. The subtractions in the includedterms will not result in new attitude error quaternions.In this thesis, the method is further developed by replacing the subtraction terms withquaternion products. The new method is tested and compared to the original EQUESTmethod and an extended Kalman filter. It is also compared to the implemented nonlinearobserver. If the computational power of the NUTS satellite is sufficiently large, a combinationof the developed EQUEST method and the nonlinear observer could be considered forthe estimation. A combination of these two attitude estimation methods is implementedand the simulation results are analyzed.
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Scott-Young, Stephen. "Integrated position and attitude determination for augmented reality systems /." Connect, 2004. http://eprints.unimelb.edu.au/archive/00000827.
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Quine, Ben. "Spacecraft guidance systems : attitude determination using star camera data." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360417.
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Duncan, Stuart. "Development and exploitation of GPS attitude determination for microsatellites." Thesis, University of Surrey, 2010. http://epubs.surrey.ac.uk/804951/.
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Pinchin, James Thomas. "GNSS Based Attitude Determination for Small Unmanned Aerial Vehicles." Thesis, University of Canterbury. Mechanical Engineering, 2011. http://hdl.handle.net/10092/5759.
Full textAbstract:
This thesis is concerned with determining the orientation of small Unmanned Aerial Vehicles(UAVs). To make commercial use of these aircraft in aerial surveying markets their attitude needs to be determined accurately and precisely throughout a survey flight.
Traditionally inertial sensors have been used on larger aircraft to estimate both position and orientation in combination with Global Navigation Satellite Systems (GNSS). High quality inertial sensors have many downsides when used on the small UAV. They are expensive, power hungry and often heavy. Inertial sensors are vulnerable to vibration, high acceleration, high rotation rate and jerk. All of these are present on the small UAV. This thesis identifies GNSS attitude determination as a potentially suitable alternative to inertial techniques.
Carrier phase GNSS attitude determination uses three or more GNSS receivers with antennas separated by a short baseline to estimate the orientation of the UAV. This technique offers low cost, high accuracy and drift-free attitude estimates. To be successfully used it requires removal of the biases present in the received GNSS signals and estimation of the integer cycle ambiguity present in the carrier phase measurement.
This thesis presents and examines the state of the art techniques for removing these biases and estimating an integer cycle ambiguity using a priori measurement of the interantenna distance. In this work a novel method is developed which uses this a priori baseline measurement to validate estimates of the carrier phase ambiguities.
In order to test these methods data has been gathered using low cost, commercially available GNSS receivers and antennas. This is the first work in which modern, low cost, GNSS equipment has been tested for use in attitude determination. It is found that the state of the art carrier phase GNSS attitude determination methods can provide an accurate attitude estimate for every set of measurements from the GNSS receivers.
However, a real UAV flight indicates that the low cost GNSS equipment does not track the GNSS signals throughout the flight. Signal outages, cycle slips and half cycle ambiguous carrier phase measurements occur due to rapid UAV manoeuvres. Having identified this problem this work goes on to replicate and quantify it through the use of a GNSS hardware simulator. Algorithms are then devised to increase the availability of the GNSS attitude solution throughout the tracking difficulties.
Complete GNSS signal tracking failures are overcome through the innovative use of kinematic and dynamic attitude models. Both types of model give an attitude solution throughout GNSS signal tracking problems without adding significant cost or weight to the system. When tracking of the GNSS carrier phase signal is possible, novel use of the carrier phase triple difference observable allows the attitude rate to be estimated even when the carrier phase measurements are half cycle ambiguous. It is shown that integer and half integer cycle slips can be removed from the measurement through the combination of the modelling and triple difference techniques.
The attitude output of both modelling and triple difference methods is used to resolve half cycle ambiguities and make full use of half cycle ambiguous data where previously it could not have been used. Success rates of up to 99.6% have been achieved for half cycle ambiguity resolution. As a result precise and accurate GNSS attitude solutions are available at nearly every epoch for which a carrier phase measurement is output by the GNSS receivers. When no measurement is available the attitude solution gracefully degrades over time.
This work makes reliable, accurate, low cost attitude determination possible on mini-UAVs.
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Puri, Varun. "Tightly coupled GPS-gyro integration for spacecraft attitude determination." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/50315.
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Ntsimane, M. H. (Mpho Hendrick). "The attitude determination and control systems (ADCS) task scheduler." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52487.
Full textAbstract:
Thesis (MScEng)--University of Stellenbosch, 2001.<br>ENGLISH ABSTRACT: A new task scheduler for the Attitude Determination and Control System (ADCS) of
the Stellenbosch University Satellite (SUNSAT) has been designed and tested on a
personal computer. This new scheduler is capable of uploading new control tasks, or
changing existing control tasks, on an individual basis. This is an improvement on the
current ADCS task scheduler, where the control tasks are hard-coded in the
scheduler, requiring the entire software image of the scheduler to be uploaded if a
new task is to be added, or an existing task is to be changed.
The new scheduler was developed using the Java programming language. The Java
ClassLoader class is used to dynamically load tasks to a linked list. The scheduler
thread runs through this linked list and schedules all the tasks that have become
schedulable. New tasks can be added to the list without stopping the scheduler.
The new scheduler has been successfully implemented on a personal computer,
laying a good foundation for implementation in an embedded environment based on
processors such as the T800 Transputer of the ADCS or the 80386 processor of the
secondary onboard computer (OBC2).<br>AFRIKAANSE OPSOMMING: 'n Nuwe taak skeduleerder vir die orientasie beheerstelsel (Engels: Attitude
Determination and Control System, of ADCS) van die Stellenbosch Universiteit
Satelliet (SUNSAT) is ontwerp en getoets op 'n persoonlike rekenaar. Hierdie nuwe
skeduleerder het die verrnoee om ekstra beheertake op te laai, of bestaande
beheertake te wysig, onafhanklik van mekaar. Dit is 'n verbetering op die huidige
ADCS taak skeduleerder waar take hard gekodeer is in die skeduleerder en waar
vereis word dat die volledige sagteware beeld van die skeduleerder opgelaai moet
word indien 'n nuwe taak bygevoeg wil word of 'n bestaande taak gewysig wil word.
Die nuwe skeduleerder is ontwikkel met behulp van die Java programmeringstaal.
Die Java C/assLoader klas is gebruik om take dinamies te laai en te voeg by 'n
skakellys. Die skeduleerder proses stap dan deur hierdie skakellys en skeduleer aile
take wat skeduleerbaar geword het. Nuwe take kan by die skakellys gevoeg word
sonder om die skeduleerder te stop.
Die nuwe skeduleerder is suksesvol ge'lmplementeer op 'n persoonlike rekenaar en Ie
'n goeie grondslag vir implementering in 'n toegewyde stelsel omgewing gebaseer op
byvoorbeeld die T800 Transputer van die ADCS of die 80386 verwerker van die
sekondere aanboord rekenaar (OBC2).
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Larsson, Lasse. "Design of spacecraft attitude determination system using MEMS sensors." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187663.
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The CubeProp module is a propulsion module developed by NanoSpace AB that will fly on-board the MIST CubeSat in 2017. NanoSpace is interested in developing an attitude determination system for the Cube-Prop module that also can be used to measure the performance of the thrusters in space. In this thesis such a system is designed and the performance is validated through numerical simulation. A method for testing the system is also chosen. The first step in designing the system is to perform a requirement analysis. This analysis leads to the decision of using only commercially available MEMS sensors. The MAX21000 gyroscope is chosen to be used after performing an initial performance calculation of the sensor together with a market survey. To determine how many gyroscopes of this types that are needed, simulations for attitude determination systems with 1, 2 and 3 gyroscopes are performed. Based on these simulations the thrust is calculated using a thrust measurement algorithm and it is concluded that the system should consist of 2 gyroscopes. The attitude determination performance and the de-spin performance is then simulated for this dual gyroscope system. The results from the simulations show that by using a dual gyroscope system the thrust can be determined down to a size of 10 µN. The mean error of the attitude after a 90 ° rotation is 0.049 °. A rotation around the z-axis of 1 ° s−1 can be de-spun so that the rotation around any body-axis is smaller then 0.02 ° s−1. The best way to test a real life model of this system is by using an air bearing table as the attitude determination and the control system can be tested simultaneously.<br>CubeProp modulen är en framdrivningsmodul avsedd för CubeSats som är utvecklad av NanoSpace AB i Uppsala. Modulen kommer att vara ett av ett flertal experiment ombord satelliten MIST som ska skjutas upp år 2017. NanoSpace vill utveckla ett system som ska sitta på CubeProp modulen för att kunna bestämma riktningen och rotationen av satelliten. Dessutom vill dom kunna mäta prestandan på modulens raketmotorer. I det här arbetet utvecklas ett sådant system och dess prestanda är utvärderad med hjälp av en numerisk simulering. Metoder för att testa en fysisk version av systemet utvärderas också. I det första steget i designprocessen görs en kravanalys. Denna analys leder till beslutet att fokusera på MEMS sensorer som redan finns ute på marknaden. Genom att göra enklare prestandaberäkningar och en marknadsundersökningar så valdes gyroskopsensorn MAX21000 för att användas i systemet. För att bestämma antalet sensorer så gjordes ett antal simuleringar med olika system som bestod av 1, 2 och 3 sensorer. Genom att att använda en egenutvecklad algoritm så beräknas den levererade kraften från raketmotorerna ut med hjälp av dom olika simuleringarna. Baserat på detta så räcker det med att använda 2 gyroskopsensorer för att systemet ska få den krävda prestandan. Prestandan i riktningsbestämmelse samt prestandan för att bromsa en rotation simuleras sedan enbart för ett system med 2 sensorer. Simuleringarna visar att detta system kan bestämma kraften från motorerna ner till en kraft på 10 µN. Medelstorleken i riktningsavikelse är enbart 0.049 ° efter en 90 ° rotation kring en axel. En initial rotation runt z-axeln på 1 ° s−1 kan stoppas av systemet så att rotationshastigheten kring alla axlar är mindre än 0.02 ° s−1. Det bästa sättet att testa en fysisk version av systemet är att använda air bearing tables eftersom man med hjälp av dessa samtidigt kan utvärdera riktningsbestämmelsen och kontrollsystemet.
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SUN, Tao. "Stereo vision–based navigation and attitude determination for CubeSat." Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21578.
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Recently, vision-based navigation systems for space manipulators have attracted a number of researchers working in this field. The technique could be used to deal with several space missions, including space debris classification and cleaning, small satellite capturing, space docking and formation flying. To generate a more accurate location and attitude, this advanced technique can be combined with other navigation methods, such as inertial measurement unit or global positioning system through a Kalman filter. The stereo vision–based navigation system is presented in this thesis. After the calibration operations to rectify the original image into the standard form, the depth map based on a semi-global matching algorithm is applied to provide a three-dimensional environment in the field of view. Because of the poor performance of this algorithm related to the low resolution and low texture of the object, a feature-based matching algorithm is designed to estimate the model of the CubeSat. This algorithm includes a series of morphological operations and feature extraction methods. A Canny detector can be used to isolate the edges from the images while the edges belong to both the target and the background. Thus, these operations can be applied to extract the edges of the CubeSat from the stereo images, combining the algorithms of the Canny detector and Graph Cut. Further, due to the specific shape of the CubeSat, the crossing points related to the edges can be used as the endpoints to estimate the model for each external plane by reprojection and triangulation. As a result, the attitude and location of the CubeSat can be determined. An experiment has been implemented to verify this design with a stereo camera, a model of CubeSat and the software.
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Gudmundson, Karl. "Ground Based Attitude Determination Using a SWIR Star Tracker." Thesis, Linköpings universitet, Reglerteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158129.
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This work investigates the possibility of obtaining attitude estimates by capturing images of stars using a SWIR camera. Today, many autonomous systems rely on the measurements from a GPS to obtain accurate position and attitude estimates. However, the GPS signals are vulnerable to both jamming and spoofing, making any system reliant on only GPS signals insecure. To make the navigation systems more robust, other sensors can be added to acquire a multisensor system. One of these sensors might be a ground based SWIR star camera that is able to provide accurate attitude estimates. To investigate if this is possible, an experimental setup with a SWIR camera was placed at the office of FOI Linköping, where the camera in a rigid position has captured images of the sky. The SWIR camera possesses several advantages over a camera operating in the visual spectrum. For example, the background radiation is weaker and the transmission through the atmosphere is higher in certain wavelength bands. The images captured by the SWIR camera was provided to a star tracker software that has been developed. The star tracker software contains algorithms to detect stars, position them in the image at subpixel accuracy, match the stars to a star database and finally output an attitude based on the stars from the image and the identified stars in the database. To further improve the attitude estimates, an MEKF was applied. The results show that attitude estimates could be obtained consistently from late evenings to early mornings, when the sky was dark. However, this required that the weather conditions were good, i.e., a limited amount of clouds. When more clouds were present, no attitude estimates could be provided for a majority of the night. The SWIR camera was also compared to a camera operating in the visual spectrum when clouds were present, to see if the results were any different. With the camera settings applied in this work, the two cameras seemed to perform equally. The accuracy of the estimated attitudes is hard to validate, since no true attitude is available. However, the variance of the estimates was low, and the major differences in the attitude estimates over a night's measurements seemed to be a drift present in all angles. The maximum estimated error in declination during a night's measurements varied from about 40 to 60 arc seconds, depending on the data set. The maximum estimated error in right ascension varied between 200 and 2000 arc seconds, and the same metric in the roll estimate were about 100 to 2500 arc seconds. The reason for the drifts is assumed to be atmospheric effects not being accounted for, and astronomical effects moving the direction of the rotation axis of the earth, creating errors in the star positions given in the database.
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Park, Keun Joo. "GPS receiver self survey and attitude determination using pseudolite signals." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/1250.
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This dissertation explores both the estimation of various parameters from a multiple antenna GPS receiver, which is used as an attitude sensor, and attitude determination using GPS-like Pseudolite signals. To use a multiple antenna GPS receiver as an attitude sensor, parameters such as baselines, integer ambiguities, line biases, and attitude, should be resolved beforehand. Also, due to a cycle slip problem a subsystem to correct this problem should be implemented. All of these tasks are called a self survey. A new algorithm to estimate these parameters from a GPS receiver is developed usingnonlinear batch filteringmethods.For convergence issues, both the nolinear least squares (NLS) and Levenberg-Marquardt (LM) methods are applied in the estimation.Acomparison ofthe NLSand LMmethods shows that the convergence of the LM method for the large initial errors is more robust than that of the NLS. In the proximity of the International Space Station (ISS), Pseudolite signals replace the GPSsignals since almostallsignals are blocked.Since the Pseudolite signals have spherical wavefronts, a new observation model should be applied. A nonlinear predictive filter, an extended Kalman filter (EKF), and an unscented filter (UF) are developed and compared using Pseudolite signals. A nonlinear predictive filter can provide a deterministic solution; however, it cannot be used for the moving case. Instead, the EKF or the UF can be used with the angular rate measurements. A comparison of EKF and UF shows that the convergence of the UF for the large initial errors is more robust than that of the EKF. Also, an alternative global navigation constellation is presented by using the Flower Constellation (FC) scheme. A comparison of FC global navigation constellation and other GPS constellations, U.S. GPS, Galileo, and GLONASS, shows that position and attitude errors of the FC constellation are smaller that those of the others.
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Mumtaz, Rafia. "Attitude Determination by Exploiting Geometric Distortions in Stero Earth Images." Thesis, University of Surrey, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518706.
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Sheridan, Kevin Francis. "GPS based position and attitude determination for airborne remote sensing." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271175.
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Sullivan, Wendy I. (Wendy Ilene). "Performance analysis of an integrated GPS/inertial attitude determination system." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/47359.
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Skinner, Robert Edmid. "Feasibility study of a moon sensor for satellite attitude determination." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50356.
Full textAbstract:
Thesis (MScEng)--University of Stellenbosch, 2005.<br>ENGLISH ABSTRACT: The purpose of this study was to investigate the feasibility of a moon sensor as an alternative
or supplemental sensor to supply attitude information to a satellite. The visibility of the moon
was evaluated with regards to that of the sun from a satellite (i.e. the feasibility of the moon
sensor is compared to that of a sun sensor).
An algorithm was developed to calculate the center of the moon, regardless of phase or
rotation, to offer increased accuracy of the center of the moon. The accuracy of this
algorithm and the possible error margins were evaluated and discussed in both ideal and
actual test cases. The sensor was implemented on embedded hardware.
The conclusion of the feasibility analysis was that the sensor would function well as a
supplemental sensor (e.g. in conjunction with a sun-sensor) rather than as an alternative
sensor. The accuracy of the moon center algorithm was satisfactory for attitude
deterrnina tion.
This sensor could thus be seriously considered for use on a future satellite.<br>AFRIKAANSE OPSOMMING: Die doel van die studie is om die lewensvatbaarheid van 'n maan-sensor, as alternatiewe of
aanvullende sensor, om oriëntasie data aan 'n sateliet te verskaf, te ondersoek. Die sigbaarheid
van die maan en die sigbaarheid van die son is met mekaar vergelyk, vanaf 'n sateliet (m.a.w.
die uitvoerbaarheid van 'n maan-sensor is vergelyk met dié van 'n son sensor).
'n Algorittne is ontwikkel om die middelpunt van die maan, ongeag van fase of rotasie,
te bereken om verhoogde akuraatheid van die maan se middelpunt te bied. Die akuraatheid
van die maan-middelpunt algoritme en moontlike foute is evalueer en bespreek in beide ideale
sowel as werklike toets gevalle. Die sensor was op hardeware geimplenteer.
Die gevolgtrekking van die lewensvatbaarheids analise is dat die sensor effektief sal
funksioneer as 'n aanvullende sensor (d.w.s saam met 'n son sensor) eerder as 'n alternatiewe
sensor. Die resultate verkry van die evaluasie van die maan-middelpunt algoritme is
bevredegind en is voldoende vir oriëntasie bepaling.
Die sensor kan dus ernstig oorweeg word vir gebruik op 'n sateliet in die toekoms.
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Tuthill, Jason D. "Design and simulation of a nano-satellite attitude determination system." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FTuthill.pdf.
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Thesis (Astronautical Engineer and M.S. in Astronautical Engineering)--Naval Postgraduate School, December 2009.<br>Thesis Advisor(s): Romano, Marcello ; Woo, Hyunwook. Second Reader: Newman, James. "December 2009." Joint authors: Description based on title screen as viewed on January 27, 2010. Author(s) subject terms: Kalman filter, Attitude determination, CubeSat, Nano-satellite, IMU, Magnetometer,Star tracker, Gyroscope. Includes bibliographical references (p. 125-128). Also available in print.
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ALI, ANWAR. "Power Management, Attitude Determination and COntrol Systems of Small Satellites." Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2535715.
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Satellites have always been considered to be extremely expensive and risky business, which not only requires extensive knowledge and expertise in this field but also huge budget. Primarily, this concept was based on initial development and launching cost. Secondly, it was also impossible to repair and substitute parts (this was true up to 1993: the first Hubble Space Telescope servicing mission), which makes design more tough because it requires advanced fault tolerance solutions and extreme reliability. But with the passage of time many space actors entered in this market. Low cost design techniques played an important role in the aerospace market growth in the past years, but they can still play a major part in future developments. At present, several private companies are also providing launch services which further lower the accumulative cost. Many universities and SMEs (Small Medium Enterprises) worldwide are also trying to reduce satellite costs. The Department of Electronics and Telecommunication (DET) at Politecnico di Torino has been working on NanoSatellites since 2002 and developed their first NanoSatellite called PiCPoT, which was intended to be launched together with other university satellites by a DNEPR LV rocket in July 2006. Unfortunately a problem in the first stage of the carrier led to the destruction of all satellites. After that DET started work on a comprehensive NanoSatellite project called AraMiS (Italian acronym for Modular Architecture of Satellites). The main idea of the AraMiS is modularity at mechanical, electronic and testing levels using Commercial-Off-The-Shelf (COTS) components. These modules can be assembled together to get the targeted mission, which allows an effective cost sharing between multiple missions. AraMiS satellites have mass up to 5kg with different shapes and dimensions. AraMiS-C1 is a CubeSat Standard satellite developed on the AraMiS approach. Four sides of the AraMiS-C1 are equipped with identical tiles called 1B8_CubePMT that mount solar panels on the exterior and a combined power management, attitude control and computing subsystem on the interior. The other two sides are devoted to the telecommunication tiles called 1B9_CubeTCT which carry a commercial deployable UHF antenna (one side) and a patch type SHF antenna (the other side).
Thesis discusses in detail the design, implementation and testing of the 1B8_CubePMT module. It is developed on the design approach of AraMiS architecture with dimension 98×82.5×1.6 mm3. 1B8_CubePMT module contains electric power supply (EPS) and attitude determination & control subsystems (ADCS) of AraMiS-C1 satellite. The integration of such a large number of systems in a small area was not a trivial job. Several techniques were employed for reduction of size, weight and power consumption of the different subsystems while still achieving best performances. COTS components were selected for the EPS subsystems, on the basis of power loss analysis and minimum dimensions which helped in efficiency enhancement and also miniaturization of the subsystems. ADCS subsystems components were also selected on the basis of minimum dimensions and lower power consumptions while still achieving targeted performances. The most interesting feature of the 1B8_CubePMT module is the design and integration of a reconfigurable magnetorquer coil within four internal layers occupying no excess space. Coils in each layer are treated separately and can be attached/detached through straps. Changing the arrangement of these straps make the magnetorquer reconfigurable. Different housekeeping sensors have been employed at various points of the 1B8_CubePMT module.
Thesis also discusses thermal modeling of CubeSat, AraMiS-C1 satellite and 1B8_CubePMT module. Thermal resistance and temperature differences between different sides of the satellites and individual tiles have been found. At the end, preliminary thermal and spin analysis of NanoSatellites have been presented.
Chapter 1 gives an introduction to the problem and proposed solutions which will be discussed in this thesis. Chapter 2 presents an introduction to AraMiS project and AraMiS-C1 satellite. Chapter 3 discusses different satellite design flow configurations and their comparison.
Chapter 4 discusses 1B8_CubePMT module which is a CubeSat standard power management tile, developed on the AraMiS concept, for AraMiS-C1 satellite. It has EPS and ADCS subsystems which are the most essential elements of any aerospace mission.
Chapter 5 deals with the design and development of the EPS system of AraMiS-C1 satellite. This chapter discusses how to reduce the size, weight and power consumption of the EPS subsystems while achieving better efficiency and fulfilling satellite power requirements. The selection of COTS components on the basis of power loss analysis and minimum dimensions is discussed in detail. Housekeeping sensors such as current, voltage and temperature sensors which are employed at different points of the 1B8_CubePMT module to cope with anomalies, have been discussed in detail in this chapter. At the end of the chapter, the designed EPS is evaluated on the basis of AraMiS-C1 power budget.
Chapter 6 discusses design and implementation of attitude determination sensors (ADS) of the AraMiS-C1 satellite. 1B8_CubePMT has three types of attitude determination sensors: sun sensor, magnetometer and gyroscope. This chapter discusses in detail the design and operation of these sensors. Chapter 7 discusses the attitude control (ADC) system of AraMiS-C1 satellite. The design and implementation of a reconfigurable magnetorquer coil which is embedded inside the 1B8_CubePMT module, is discussed in detail. The designed magnetorquer has been evaluated on different parameters and compared with the magnetic actuator already available in the market. In chapter 8 testing procedure and results of 1B8_CubePMT subsystems are discussed in detail.
Chapter 9 presents thermal modelling of NanoSatellites. Detailed and simplified thermal models of CubeSat panel have been discussed. Thermal resistances measured through both models are compared. Generic thermal model of a CubeSat is presented. Utilizing the proposed models, thermal resistance of 1B8_CubePMT and AraMiS-C1 are measured. In order to verify the theoretical results, the thermal resistance of the AraMiS-C1 is measured through an experimental setup.
Chapter 10 discusses preliminary thermal and spin analysis of NanoSatellites in space environment. All the heat sources and their effects on the satellite have been discussed. A thermal balance equation has been established and satellite temperature for different structures and various conditions has been found. At the end a satellite spin analysis on the basis of different absorption coefficient related with colors, has been discussed.
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Keil, Elizabeth Marie. "Kalman Filter Implementation to Determine Orbit and Attitude of a Satellite in a Molniya Orbit." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/49102.
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This thesis details the development and implementation of an attitude and orbit determining Kalman filter algorithm for a satellite in a Molniya orbit. To apply the Kalman Filter for orbit determination, the equations of motion of the two body problem were propagated using Cowell's formulation. Four types of perturbing forces were added to the propagated model in order to increase the accuracy of the orbit prediction. These four perturbing forces are Earth oblateness, atmospheric drag, lunar gravitational forces and solar radiation pressure. Two cases were studied, the first being the implementation of site track measurements when the satellite was over the ground station. It is shown that large errors, upwards of ninety meters, grow as time from last measurement input increases. The next case studied was continuous measurement inputs from a GPS receiver on board the satellite throughout the orbit. This algorithm greatly decreased the errors seen in the orbit determining algorithm due to the accuracy of the sensor as well as the continuous measurement inputs throughout the orbit. It is shown that the accuracy of the orbit determining Kalman filter also depends on the length of time between each measurement update. The errors decrease as the time between measurement updates decreases. Next the Kalman filter is applied to determine the satellite attitude. The rotational equations of motion are propagated using Cowell's Formulation and numerical integration. To increase the fidelity of the model four disturbing torques are included in the rotational equations of motion model: gravity gradient torque, solar pressure torque, magnetic torque, and aerodynamic torque. Four cases were tested corresponding to four different on board attitude determining sensors: magnetometer, Earth sensor, sun sensor, and star tracker. A controlled altitude path was chosen to test the accuracy of each of these cases and it was shown that the algorithm using star tracker measurements was three hundred times more accurate than that of the magnetometer algorithm.<br>Master of Science
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Vogt, Jay D. "Attitude determination of a three-axis stabilized spacecraft using star sensors." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA374426.
Full textAbstract:
Thesis (M.S. in Astronautical Engineering) Naval Postgraduate School, December 1999.<br>"December 1999". Thesis advisor(s): Titus, Harold A. ; Agrawal, Brij. Includes bibliographical references (p. 67). Also available online.
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Purivigraipong, S. "Study of spacecraft attitude determination from phase information of GPS signals." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/843145/.
Full textAbstract:
In this research study, several new algorithms are developed to achieve spacecraft attitude determination from carrier phase information of GPS (Global Positioning System) signals. The first focus is on resolving integer ambiguity in carrier phase difference measurements. A newly developed algorithm based on Gram-Schmidt Orthonormalisation (GSO) is proposed for medium length baseline observations. Using this newly developed attitude algorithm from vector observations, an instantaneous estimated attitude solution is obtained, which we call 'coarse attitude', from only four phase measurements collected from only two baseline observations. Then a 'fine' attitude solution from all phase measurements is estimated, using a sophisticated Kalman filtering estimator, once integer ambiguity has been resolved. The second focus is on estimating the relative phase offset error (line bias) in carrier phase difference measurements. A newly developed block bias search is proposed which finds an initially plausible solution of line bias for each individual baseline. The line bias from all phase measurements collected from each individual baseline is then re-estimated using a developed recursive least squares (RLS) estimator. A newly developed parallel architecture GPS receiver is being flown on the UoSat-12 minisatellite, with the capability for simultaneous measurements from 24 channels for attitude sensing. The final goal of this research study was to apply the developed algorithms to real GPS data, and a number of data files of phase differences of GPS signals logged on UoSat-12 were tested. Independent ADCS (Attitude Determination and Control System) data was used for the reference attitude determination. The results show that an instantaneous attitude error less than 4 degrees is achieved during coarse attitude acquisition, relative to the reference ADCS system. When all measurements are processed during fine attitude tracking, the error in attitude estimation is reduced to one degree error (1 sigma RMS), without any error mitigation for multipath, relative to the reference ADCS system.
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Marreiros, Joao Paulo Ramalho. "Performance analysis of GPS attitude determination in a hydrographic survey launch." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ30020.pdf.
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Greenfield, Nathan Joseph. "Low cost range and attitude determination solution for small satellite platforms." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/greenfield/GreenfieldN0509.pdf.
Full textAbstract:
The ability to determine the range and attitude between two satellites can be a challenging venture. It can be made more challenging when considering the use of such a system on a small satellite. Successful implementation of a small and low power range and attitude sensor could open potential doors to multiple small satellite constellations and formation flying maneuvers. After successfully demonstrating an electromagnetic docking system on a one-dimensional air track, it was determined that continued work into two and three-dimensional systems would require a more functional range and attitude sensor than was originally used. Such a sensor would have to be small enough for use aboard a small satellite, require little power while operating and provide accurate data over the required range of operation, all while maintaining a minimal monetary cost. The SATellite Range and Attitude Imaging SystEm (SATRAISE) was developed to meet this demand. In order to meet all of the listed requirements, a system based on an embedded Linux computer platform was developed. The hardware for the system utilized consumer grade, commercially available parts, including a standard computer webcam and LEDs. The software for the system made use of existing image processing libraries in order to facilitate the detection and identification of target points in frames captured by the webcam. Following successful integration of the hardware and implementation of the required software, the SATRAISE was characterized under a variety of operating conditions in order to verify the accuracy, stability and power requirements of the system. The results showed that the SATRAISE met or exceeded all of the established design goals.
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Awuah-Baffour, Robert. "Investigation on kinematic determination of highway geometric characteristics by attitude GPS." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/21657.
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Steyn, Willem Hermanus. "A multi-mode attitude determination and control system for small satellites." Thesis, Stellenbosch : Stellenbosch University, 1995. http://hdl.handle.net/10019.1/54640.
Full textAbstract:
Thesis (PhD)--Stellenbosch University, 1995.<br>ENGLISH ABSTRACT: New advanced control techniques for attitude determination and control of small (micro)
satellites are presented. The attitude sensors and actuators on small satellites are limited in
accuracy and performance due to physical limitations, e.g. volume, mass and power. To
enhance the application of sophisticated payloads such as high resolution imagers within these
confinements, a multi-mode control approach is proposed, whereby various optimized
controller functions are utilized during the orbital life of the satellite.
To keep the satellite's imager and antennas earth pointing with the minimum amount of control
effort, a passive gravity gradient boom, active magnetic torquers and a magnetometer are
used. A "cross-product" detumbling controller and a robust Kalman filter angular rate
estimator are presented for the preboom deployment phase. A fuzzy controller and
magnetometer full state extended Kalman filter are presented for libration damping and Z-spin
rate control during inactive imager periods.
During imaging, when high performance is required, additional fine resolution earth horizon,
sun and star sensors plus 3-axis reaction wheels are employed. Full state attitude, rate and
disturbance estimation is obtained from a horizon/sun extended Kalman filter. A quaternion
feedback reaction wheel controller is presented to point or track a reference attitude during
imaging. A near-minimum time, eigenaxis rotational reaction wheel controller for large
angular maneuvers.
Optimal linear quadratic and minimum energy algorithms to do momentum dumping using
magnetic torquers, are presented. A new recursive magnetometer calibration method is
designed to enhance the magnetic in-flight measurements. Finally, a software structure is
proposed for the future onboard implementation of the multi-mode attitude control system.<br>AFRIKAANSE OPSOMMING: Nuwe gevorderde beheertegnieke vir die oriëntasiebepaling en -beheer van klein (mikro-)
satelliete word behandel. Die oriëntasiesensors en -aktueerders op klein satelliete het 'n
beperkte akkuraatheid en werkverrigting as gevolg van fisiese volume, massa en kragleweringbeperkings.
Om gesofistikeerde loonvragte soos hoë resolusie kameras binne hierdie
tekortkominge te kan hanteer, word 'n multimode beheerbenadering voorgestel. Hiermee kan
'n verskeidenheid van optimale beheerfunksies gedurende die wentelleeftyd van die satelliet
gebruik word.
Om die satellietkamera en -antennas aardwysend te rig met 'n minimale beheerpoging, word 'n
passiewe graviteitsgradiëntstang, aktiewe magneetspoele en 'n magnetometer gebruik. 'n
"Kruisproduk" onttuimellings beheerder en 'n robuuste hoektempo Kalmanfilter afskatter is
ontwikkel vir die periode voordat die graviteitsgradiëntstang ontplooi word. 'n Wasige
beheerder en 'n volledige toestand, uitgebreide Kalmanfilter afskatter is ontwikkel om librasiedemping
en Z-rotasietempo beheer te doen gedurende tydperke wanneer die kamera onaktief
is.
Gedurende kamera-opnames word hoë werkverrigting verlang. Fyn resolusie aardhorison, son
en stersensors met 3-as reaksiewiele kan dan gebruik word. 'n Volledige oriëntasie, hoektempo
en steurdraaimoment Kalmanfilter afskatter wat inligting van bogenoemde sensors
gebruik, is ontwikkel. 'n “Quaternion” reaksiewiel terugvoerbeheerder waarmee die satelliet
na verwysings oriëntasiehoeke gerig kan word of waarmee oriëntasiehoektempos gevolg kan
word, word behandel. 'n Naby minimumtyd, "eigen"-as reaksiewielbeheerder vir groothoek
rotasies is ontwikkel.
Optimale algoritmes om momentumontlading van reaksiewiele met lineêre kwadratiese en
minimumenergie metodes te doen, word afgelei en aangebied. 'n Nuwe rekursiewe kalibrasietegniek
waarmee 'n magnetometer outomaties gedurende vlug ingestel kan word, is ontwikkel.
Ten slotte, word 'n programstruktuur voorgestel vir aanboord implementering van die nuwe
multimode beheerstelsel.
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Boldu, O. Farrill Treviño Joan Jordi. "Attitude Determination and Control System of a CubeSat in Suborbital Flight." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-292503.
Full textAbstract:
The Bistable Boom Dynamic Deployment (B2D2) experiment aims to successfully demonstrate the deployment of a 2 meter self-deployable boom in order to offer an efficient alternative for small satellites to conduct higher quality magnetic field measurements. The boom will be placed in a free falling unit, following the CubeSat standard. To obtain reliable results from the deployment, the tumbling rate of the free falling unit must be reduced to acceptable levels. Two cameras located in the free falling unit will record the boom deployment, meaning that they will need to be pointed in the opposite direction of the sun vector to obtain optimal results. To meet these requirements an Attitude Determination and Control System (ADCS) is needed. In this thesis the design, implementation and testing of the ADCS is presented. For B2D2 experiment the ADCS has been developed using a feedback loop where three reaction wheels are used to control the orientation. The attitude will be determined by means of five coarse sun sensors, a three axis magnetometer and an angular rate sensor. The attitude is estimated in two stages: first a deterministic approach computes the instantaneous attitude and the result is then complemented with an multiplicative extended Kalman filter. Finally, a non-linear control law is implemented to command the actuators and close the loop.<br>Bistable Boom Dynamic Deployment (B2D2) experimentet ämnar att demonstrera utfällningen av en 2-meter lång självutvecklande bom för att erbjuda ett effektivt alternativ för små satelliter att genomföra magnetfältmätningar av högre kvalitet. Bommen placeras i en fritt fallande enhet, utformad enligt CubeSat-standarden. För att få tillförlitliga resultat måste tumlingshastigheten för den fritt fallande enheten reduceras till acceptabla nivåer. Den fritt fallande enheten innehåller även två kameror, vilka ska spela in utfällningen av bommen och för bästa resultat bör kamerorna peka bort från solen. För att uppfylla dessa krav behövs ett attityd bestämnings- och kontrollsystem (ADCS). I denna avhandling presenteras utvecklingen, implementeringen och testning av ADCS systemet. För B2D2 experimentet har ett ADCS utvecklats med hjälp av en återkopplad kontroll loop där tre reaktionshjul används för att kontrollera orienteringen. Experimentets attityd bestäms med hjälp av fem grova sunsensorer, en treaxlig magnetometer samt ett gyroskop. Attityden uppskattas i två steg: först beräknas en deterministiskt metod den momentana attityden, sedan kompletteras resultatet med ett multiplikativt utökat Kalman-filter. Slutligen, implementeras en olinjär kontrollag för att styra reaktionshjulen och stänga kontroll loopen.