Dissertations / Theses: 'Aeronautical satellite communication'

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Moreland, Kenneth W. (Kenneth William) Carleton University Dissertation Engineering Electrical. "Ocean scatter propagation models for aeronautical and maritime satellite communication applications." Ottawa, 1987.

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Ben, Mahmoud Mohamed Slim. "Addressing Security Challenges in Emerging Data-based Aeronautical Communications." Thesis, Toulouse, INSA, 2012. http://www.theses.fr/2012ISAT0006/document.

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Ce travail de thèse s'intéresse à la sécurité des futures communications aéronautiques de donnée. Le travail est divisé en trois grandes parties. La première contribution est une architecture de sécurité adaptative pour les communications aéronautiques intégrant un segment sol-bord par satellite. Un module de gestion de la sécurité a été conçu, développé, puis validé lors de la phase finale d'intégration du projet FAST (Fibre-like Aircraft Satellite Communications). La deuxième contribution est une méthodologie quantitative d'estimation du risque lié à la sécurité réseau. L'originalité de notre approche est d'être basée sur la notion de propagation du risque au sein des différents noeuds du réseau. Commecas d'étude, un réseau de communication aéroportuaire utilisant le protocole AeroMACS a été étudié dans le cadre du projet SESAR (Single European Sky ATM Research). La troisième contribution est une infrastructure à clés publiques (PKI) qui permet d'optimiser les échanges de signalisation (échanges de clés, certificats, vérification des signatures) entre l'avion et l'autorité de certification au sol. Le modèle de PKI proposé est un modèle hiérarchique utilisant la certification croisée entre les autorités de certification mères This research work deals with the information and network security in the aeronautical communication domain. Three fundamental research axes are explored. First, a quantitative network security risk assessment methodology is proposed. Our approach is based on the risk propagation within the network nodes. As study cases, the algorithm has been validated in the scope of the European industrial project entitled SESAR (Single European Sky ATM Research) and the Aerospace Valley FAST (Fibrelike Aircraft Satellite Communications). Particularly, experimental results relative to the case study devoted to the FAST project shown that the global network risk in the non secured system architecture is relatively high, meaning the system needs more consideration from a security point of view. To cope with this issue, an adaptive security management framework for a satellite-based aeronauticalcommunication architecture has been proposed as a second contribution. A security manager module has been designed, implemented, then tested in the scope of the FAST project. Finally, as the security primitives used in the adaptive security management framework need to be efficiently exchanged, the last contribution consists in a scalable PKI adapted for the upcoming network-enabled aircraft. The idea is to minimize the air-ground additional overhead induced by the security procedures (keys, digital certificates, revocation/verification procedures). The PKI model we propose is a cross-certified multirooted hierarchical model

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Holzbock, Matthias. "Mobile multimedia service provisioning with collective terminals in broadband satellite networks : an approach for systematic satellite communication system design for service provisioning to collective mobile terminals, including mobile satellite channel modelling, antenna pointing, hierarchical multi-service dimensioning and aeronautical system dimensioning." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5657.

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This work deals with provisioning of communication services via satellites for collectively mobile user groups in a heterogeneous network with several radio access technologies. The extended use of personalised user equipment beyond the coverage of one single terrestrial network by means of a satellite transport link, represents an increasingly important trend in mobile satellite communication. This trend is confirmed by the commercial introduction of broadband satellite communication to mobile terminals mounted on vehicles, trains, ships or aircraft. This work provides a consequent and structured approach for provisioning of services to broadband satellite terminals for mobile user groups and addresses: -- a systematic satellite communication system design process for collective mobile terminals; -- mobile satellite modelling at a wide range of frequencies, including current and potential frequencies; -- an optimised Pointing Acquisition and Tracking (PAT) system design including characterisation of moments for vehicle types of all mobile scenarios; -- a general hierarchical multi-service dimensioning methodology for collectively mobile user groups, including voice, data, and multimedia services; -- an aeronautical system dimensioning scheme with (capacity and handover) requirements analysis and evaluation of results for different satellite scenarios.

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Hradílek, Ondřej. "Automatické ověření zaměřovací funkce letecké satelitní antény." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220977.

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This diploma thesis provides an overview and basic principles of satellite communication systems. Further is description of specific aerial satellite communication system ARINC 791. The practical part includes proposals of the system for automated verification targeting functionality of an air satellite antenna, which has been carried out in Honeywell laboratory conditions. The selected implementation is realized and used for automated verification targeting functionality of an air satellite antenna. The results are graphically evaluated.

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Riesing, Kathleen Michelle. "Portable optical ground stations for satellite communication." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119269.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018. 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 113-125). Small satellite technical capabilities continue to grow and launch opportunities are rapidly expanding. Several commercial constellations of small satellites for Earth observation and communications are making their way onto orbit, increasing the need for high bandwidth data downlink. Laser communications (lasercom) has the potential to achieve high data rates with a reduction in power and size compared to radio frequency (RF) communications, while simultaneously avoiding the significant regulatory burden of RF spectrum allocation. Lasercom benefits from high carrier frequencies and narrow beamwidths, but the resulting challenge is to precisely point these beams between transmit and receive terminals. Arcsecond to sub-arcsecond pointing is required from both the space terminal and the ground station. While existing lasercom ground stations have primarily utilized professional telescopes at observatory-class facilities, making optical ground stations more affordable and transportable is a key enabler for expanding lasercom to small satellites and new applications, as well as establishing networks to mitigate the effects of weather. We describe the development of the Massachusetts Institute of Technology Portable Telescope for Lasercom (MIT-PorTeL) utilizing an amateur telescope augmented with an externally mounted receiver assembly. The ground station has a 28 cm aperture and utilizes a star tracker for automated calibration. The ground station reduces mass by at least 10x and cost by at least 100 x over existing optical ground stations. We present a ground station architecture that enables deployment in less than one hour and that is capable of tracking satellites in low-Earth orbit. We describe the receiver assembly and fine pointing system that enables arcseconds-level pointing accuracy. Finally, we present results from testing the ground station on the roof of an MIT building tracking a star and tracking the International Space Station. by Kathleen Michelle Riesing. Ph. D.

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Kingsbury, Ryan W. "Optical communications for small satellites." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101444.

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Thesis: Ph. D., 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 115-124). Small satellites, particularly CubeSats, have become popular platforms for a wide variety of scientific, commercial and military remote sensing applications. Inexpensive commercial o the shelf (COTS) hardware and relatively low launch costs make these platforms candidates for deployment in large constellations that can offer unprecedented temporal and geospatial sampling of the entire planet. However, productivity for both individual and constellations of CubeSats in low earth orbit (LEO) is limited by the capabilities of the communications subsystem. Generally, these constraints stem from limited available electrical power, low-gain antennas and the general scarcity of available radio spectrum. In this thesis, we assess the ability of free space optical communication (lasercom) to address these limitations, identify key technology developments that enable its application in small satellites, and develop a functional prototype that demonstrates predicted performance. We first establish design goals for a lasercom payload archi- tecture that offers performance improvements (joules-per-bit) over radio-frequency (RF) solutions, yet is compatible with the severe size, weight and power (SWaP) constraints common to CubeSats. The key design goal is direct LEO-to-ground downlink capability with data rates exceeding 10 Mbps, an order of magnitude better than COTS radio solutions available today, within typical CubeSat SWaP constraints on the space terminal, and with similar COTS and low-complexity constraints on the ground terminal. After defining the goals for this architecture, we identify gaps in previous implementations that limit their performance: the lack of compact, power-efficient optical transmitters and the need for pointing capability on small satellites to be as much as a factor of ten better than what is commonly achieved today. One approach is to address these shortcomings using low-cost COTS components that are compatible with CubeSat budgets and development schedules. In design trade studies we identify potential solutions for the transmitter and pointing implementation gaps. Two distinct transmitter architectures, one based on a high-power laser diode and another using an optical amplifier, are considered. Analysis shows that both configurations meet system requirements, however, the optical amplifier offers better scalability to higher data rates. To address platform pointing limitations, we dene a staged control framework incorporating a COTS optical steering mechanism that is used to manage pointing errors from the coarse stage (host satellite body-pointing). A variety of ne steering solutions are considered, and microelectromechanical systems (MEMS) tip-tilt mirrors are selected due to their advantage in size, weight and power. We experimentally validate the designs resulting from the trade studies for these key subsystems. We construct a prototype transmitter using a modified COTS fiber amplifier and a directly-modulated seed laser capable of producing a 200mW average power, pulse position modulated optical output. This prototype is used to confirm power consumption predictions, modulation rate scalability (10 Mbps to 100 Mbps), and peak transmit power (e.g., 24.6W for PPM-128). The transmitter optical output, along with a simple loopback receiver, is used to validate the sensitivity of the avalanche photodiode receiver used for the ground receiver in the flight experiment configuration. The MEMS fine steering mechanisms, which are not rated for space use, are characterized using a purpose-built test apparatus. Characterization experiments of the MEMS devices focused on ensuring repeatable behavior (+/-0:11 mrad, 3-[sigma]) over the expected operating temperature range on the spacecraft (0°C to 40°C). Finally, we provide an assessment of the work that remains to move from the prototype to flight model and into on-orbit operations. Space terminal packaging and integration needs, as well as host spacecraft interface requirements are detailed. We also describe the remaining ground station integration tasks and operational procedures. Having developed a pragmatic COTS-based lasercom architecture for CubeSats, and having addressed the need for a compact laser transmitter and optical ne steering mechanisms with both analysis and experimental validation, this thesis has set the stage for the practical use of lasercom techniques in resource-constrained CubeSats which can yield order-of-magnitude enhancements in communications link eciency relative to existing RF technologies currently in use. by Ryan W. Kingsbury. Ph. D.

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Yoon, Hyosang. "Pointing system performance analysis for optical inter-satellite communication on CubeSats." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113743.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2017. Cataloged from PDF version of thesis. Includes bibliographical references (pages 175-181). Free-space optical communication using lasers (lasercom) is a leading contender for future space-based communication systems with potential advantages over radio frequency (RF) communication systems in size, weight, and power consumption (SWaP). Key benefits are due to the shorter wavelength: additional bandwidth and narrow beam width. The narrower beam supports higher energy density for a given aperture size, so that lasercom can transmit data at the same rate with smaller SWaP as well as improve link security since the beam footprint is smaller. Lasercom is an attractive option for improving inter-satellite links (ISL) for resource-constrained CubeSats, which have emerged as a standard form of a small satellite since 1999. However, lasercom requires much more accurate pointing because of its narrower beam width. Accurate pointing is not trivial for most CubeSat platforms due to their resource constraints. A typical 3U CubeSat is 34 cm x 10 cm x 10 cm with less than 5 kg mass and about 10 W of available orbit-average power. This thesis presents pointing and tracking technologies to support lasercom on CubeSats. It covers three critical issues: (1) attitude determination and control of CubeSats, (2) relative orbit determination, and (3) development of a miniaturized fine beam pointing module. New attitude determination and control algorithms are developed, simulated, and validated with hardware in the loop demonstrations; results indicate that lasercom at data rates competitive with or better than RF is feasible on CubeSats. For attitude determination and control (ADC), this thesis develops a new attitude estimation algorithm, which is called Attitude and Parameter estimation Kalman filter (APKF). Attitude determination (AD) is thought to be more challenging than attitude control (AC) for CubeSats because of the limited capabilities of sensors that are compatible with the small form factor and resource constraints of CubeSats. The largest difference between a CubeSat and a larger satellite is the gyroscopes that measure rotation rates. Since a CubeSat is normally not able to accommodate high quality gyroscopes, the APKF is used to improve estimation without relying on gyroscope measurements. The APKF estimates CubeSat attitude and body rates as well as other unknown parameters such as the moment of inertia (MOI), actuator alignment, and the residual dipole moments. For relative orbit determination, this thesis describes an estimation algorithm that fuses different types of orbital measurements using the Kalman filter. There are three measurements that can be used in the relative orbit estimation for low earth orbiting (LEO) lasercom crosslink CubeSats: Global Navigation Satellite System (GNSS) navigation solutions for an individual satellite (e.g. Satellite A or "SatA"), beacon beam measurements at SatA, and GNSS navigation solutions of the other satellite (SatB) transferred through ground station networks. The GNSS and beacon are measured at SatA, so these can be assumed to have negligible time delay, but the arrival time of the SatB navigation solutions will be an out-of-sequence measurement (OOSM) whose arrival time will be delayed due to the ground station relay. To fuse the sensor data with different measurement times, a new algorithm called the Augment Fixed- Lag Smoother (AFLS) is developed. To update the Kalman filter with an OOSM, the AFLS generates the estimates at the measurement time of the OOSM by interpolation. The AFLS is applied to a nonlinear system as the extended AFLS (EAFLS). The Satellite Tracking Kalman Filter (STKF) is developed using the EAFLS. The fine pointing system (FPS) is necessary because while the CubeSat attitude determination and control and the orbit determination developments cover the Cube- Sat's body pointing capability, due to the extremely narrow beam desired for high-rate laser communications, body pointing alone cannot satisfy the beam pointing requirements. The example case used in this thesis is a CubeSat design concept mission with an inter-satellite laser communication link. To reduce the pointing error, a FPS needs to be implemented as the final stage for beam pointing. This thesis demonstrates the feedback control loop of the FPS using a hardware-in-the-loop test. A key component of the FPS is the miniaturized micro-electro-mechanical systems (MEMS) fast steering mirror (FSM) which is the actuator used to point the laser beam. Using a commercial-off-the-shelf (COTS) MEMS FSM that is also planned for use on the flight module, the fine pointing control loop has been demonstrated with results that show that it is feasible to meet the pointing requirement for a 3U CubeSat mission whose goal is 20 Mbps link at 25 km to 1000 km crosslink range. By developing and demonstrating the critical technologies for both spacecraft body pointing and the fine beam pointing, this thesis has demonstrated the feasibility of a CubeSat lasercom crosslink at a data rate and form factor that can outperform RF, leading to a high-speed and secure ISL for CubeSats. by Hyosang Yoon. Ph. D.

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Lohmeyer, Whitney Quinne. "Data management of geostationary communication satellite telemetry and correlation to space weather observations." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79333.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2013. This electronic version was submitted and approved by the author's academic department as part of an electronic thesis pilot project. The certified thesis is available in the Institute Archives and Special Collections. Cataloged from department-submitted PDF version of thesis. Includes bibliographical references (p. 86-89). To understand and mitigate the effects of space weather on the performance of geostationary communications satellites, we analyze sixteen years of archived telemetry data from Inmarsat, the UK-based telecommunications company, and compare on-orbit anomalies with space weather observations. Data from multiple space weather sources, such as the Geostationary Operational Environmental Satellites (GOES), are compared with Inmarsat anomalies from 1996 to 2012. The Inmarsat anomalies include 26 solid-state power amplifier (SSPA) anomalies and 226 single event upsets (SEUs). We first compare SSPA anomalies to the solar and geomagnetic cycle. We find most SSPA anomalies occur as solar activity declines, and when geomagnetic activity is low. We compare GOES 2 MeV electron flux and SSPA current for two weeks surrounding each anomaly. Seventeen of the 26 SSPA anomalies occur within two weeks after a severe space weather event. Fifteen of these 17 occur after relativistic electron events. For these fifteen, peak electron flux occurs a mean of 8 days and standard deviation of 4.7 days before the anomaly. Next, we examine SEUs, which are unexpected changes in a satellite's electronics, such as memory changes or trips in power supplies. Previous research has suggested that solar energetic protons (SEPs) cause SEUs. However, we find that SEUs for one generation of satellites are uniformly distributed across the solar cycle. SEUs for a second generation of satellites, for which we currently have only half a solar cycle of data, occur over an order of magnitude more often than the first, even during solar minimum. This suggests that SEPs are not the primary cause of SEUs, and that occurrence rates differ substantially for different satellite hardware platforms with similar functionality in the same environment. These results will guide design improvements and provide insight on operation of geostationary communications satellites during space weather events. by Whitney Quinne Lohmeyer. S.M.

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Underwood, Jennifer E. (Jennifer Elizabeth). "Distributed satellite communications system design : first-order interactions between system and network architectures." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32455.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005. Includes bibliographical references (p. 159-165). Humanity now exists in the midst of the fast-moving Information Age, a period of history characterized by fast travel and even faster information transfer. As data becomes seemingly more valuable than physical possessions, the introduction of exciting applications for communications services becomes ever more critical for the success - and in some cases, survival - of businesses and even nations. While the majority of these innovations have occurred over cable and fiber, a number of the most socially significant have occurred due to the introduction of satellites. Terrestrial fiber and cable systems have a number of advantages, but the extent of their reach and the cost of installation - in terms of both capital and time - favor industrialized nations over more remote and underdeveloped communities. Even as satellites offer the only real chance for ultimate communications ubiquity and true global unity, there remains a significant cost-benefit barrier. Few commercial satellite systems have succeeded economically without first falling victim to bankruptcy. The upfront capital required to implement a satellite communications system is staggering, and historically satellite companies have failed to adequately match capacity and service options to the current and actual future demand. The design process itself is an inherent limiting factor to the achievable cost and performance of a system. (cont.) Traditionally, the first step toward designing satellite communication systems - as well as terrestrial, sensor web, and ad hoc networks - has been to specify the system topology (e.g., the orbits of the satellites and the locations of the ground stations) based on the desired market and then to design the network protocols to make the most of the available resources. Such a sequential process assumes that the design of the network architecture (e.g., protocols, packet structure, etc) does not drive the design of the system architecture (e.g., constellation topology, spacecraft design, etc). This thesis will show that in the case of Ka-band distributed satellite communication systems this fundamental assumption is not valid, and can have a significant impact on the success (cost, capacity, customer satisfaction) of the resulting satellite communication system. Furthermore, this thesis will show that how a designer values performance during the design and decision process can have a substantial impact on the quality of the design path taken through the trade space of possible joint architectures. by Jennifer E. Underwood. S.M.

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Cunniffe, Peter. "Misreading history--government intervention in the development of commercial communications satellites." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/12780.

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Szajnfarber, Zoe. "What drives spacecraft innovation? : a quantitative analysis of communication satellite history." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/57700.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2009. Cataloged from PDF version of thesis. Includes bibliographical references (p. 58-61). The overall goal of this research is to develop a better understanding of how innovation can, and should, happen in the space sector. Part A: Towards an Empirical Measure of Spacecraft Innovation, frames the discussion of innovation in the space sector and creates a platform for future analysis. To accomplish this, it addresses three aspects of the task of measurement. First, it surveys several distinct literatures to establish precedence for defining a spacecraft innovation metric. Second, the conceptual trade-offs associated with adopting this principle in the context of communication satellites are elucidated and treated. By defining product boundaries along the dimensions of product scope and market transactions, three paradigms for measurement are proposed; namely, 1) the communication satellite enterprise; 2) the physical satellite; and 3) communication service. Third, under the constraints of historical data collection realities, next-best estimators are put forward as surrogates for the parameters required in implementing the proposed metrics. Based on these surrogates, the relative merits of each measurement paradigm are illustrated through sample analyses. (cont.) Part B: Lessons from Communication Satellite History (1964-2006), captures the first detailed attempt to quantitatively analyze innovation in the space sector. Building on the communication satellite innovation metric (developed in Part A) and a spacecraft innovation framework (developed as part of ongoing work) Part B presents a preliminary model of communication satellite innovation. In addition to innovation being a function of the rate of performance normalized by price, spacecraft innovation is shown to be strongly influenced by characteristics of the customer-contractor contractual relationship. Specifically, DoD contracts tend to result in a lower level of innovation on average as compared to other customers and particular customer-contractor pairs perform differently and exhibit a second order relationship in time. No pair was observed to sustain better than average innovation in the long run. by Zoe Szajnfarber. S.M.in Technology and Policy S.M.

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Chang, Darren Datong 1977. "Quantifying technology infusion and policy impact on low earth orbit communication satellite constellations." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17759.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2004. Includes bibliographical references (p. 199-204). Technology infusion and policy implementation bring impacts to the trade space of complex engineering systems. This work describes in detail the frameworks for quantitative analyses on these impacts, demonstrates their use on the sample system, and presents the analysis results. The low earth orbit (LEO) communication satellite constellation system serves as the platform for carrying out the system trade space analysis. The system is reproduced in computer environment in the form of a multiple-input-output MATLAB model. The model contains multiple modules that incorporate the physics, economy, and policies of the real-world system. The inputs to the model are system design variables and the outputs are system performance, capacity, and cost. The Pareto optimal solution set of the baseline trade space is generated by the model using a full-factorial run that covers the entire design space. To simulate technology infusion, technical and cost attributes of four new technologies are quantified and infused into the system model. The infusion of technologies and combinations of technologies into the system is simulated. Policy implementation is simulated by changing the policy constraints in the model. The technology-infused trade space and policy-implemented trade space have new sets of Pareto optimal solutions. By comparing these solution sets with the baseline optimal solution set in the objective space, we can quantify the impact of technology infusion and policy impact. In conclusion, the methodologies of quantifying the impact of technology infusion and policy implementation on complex engineering systems is repeatable and has been tested against real-world systems. (cont.) The information generated demonstrates their usefulness to technology selection and policy decision-making processes. by Darren Datong Chang. S.M.

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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.

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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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Fogle, Faisal A. (Faisal Adam). "Liquid lens beam steering and environmental testing for the miniature optical steered antenna for inter-satellite communication." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127076.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, May, 2020 Cataloged from the official PDF of thesis. Includes bibliographical references (pages 105-106). We investigate the feasibility of using a series of deformable liquid lenses to achieve wide-angle beam steering for CubeSat laser communication (lasercom) crosslinks. Liquid lenses are lenses that can non-mechanically alter focal length based on an applied voltage or current. We evaluate two commercial liquid lens manufacturers, Corning Varioptic and Optotune. Corning Varioptic lenses rely on the principle of electrowetting for lens actuation, while Optotune lenses are driven by a voice coil. For steering, a liquid lens is placed offset from the optical axis. Varying the liquid lens focal length will cause the beam to steer in 1D by refraction, but also causes a change in beam divergence. Adding an on-axis focusing liquid lens allows this beam divergence to be controlled dynamically. Adding a second off-axis liquid lens, displaced in the other axis, creates 2D steering. A fisheye lens can then amplify the steering cone to full hemispherical coverage [1]. However, liquid lenses were not designed for nor have ever been flown in space. In this work, we show that both types of liquid lens passed initial space qualification testing. Testing activities included vacuum survivability, vacuum operation, and thermal-vacuum (TVAC). The Corning A39N0 and Optotune EL-16-40-TC liquid lenses provided nearly identical steering transfer functions in vacuum as in ambient. The Corning and Optotune lenses achieved 2.7° and 8.6° angular range with collimated output, respectively, although these ranges were truncated by the camera field of view and focusing lens optical power range. The steering curves were linear, so, allowed to steer their full range, approximately 4.3° and 21.5° of steering range can be expected. In TVAC, the Corning lens operated from -25°C to 75°C and the Optotune lens from -40°C to 70°C. The lenses never failed in this testing, rather, external factors forced the termination of testing. Thus, even more temperature range may be expected. The lens steering angles drifted with temperature at 0.24 mrad/°C for the A39N0 and 0.19 mrad/°C for the EL-16-40-TC. The worst case hysteresis error, the difference in the steering transfer function between increasing and decreasing input values, was 0.3 mrad for the Corning lens and 1 mrad for the Optotune lens. A beam quality analysis was conducted in Zemax to identify the impact of beam refraction through the liquid lenses on transmit gain. Worst case values for transmit losses were found to be -0.5 dB for the Corning lens and -0.4 dB for the Optotune lens. However, at positive steering angles, an overall transmit boost can be expected due to the impact of beam expansion through the focusing liquid lens. We discuss key terminal design trade-offs, and a prototype transmit-only terminal was created and demonstrated full hemispherical steering in a lab setting. Future testing will investigate the beam quality and divergence for wide angle steering to quantify link distances for free space optical communications using this method of beam steering. A compact hemispherical laser transceiver will enable efficient, high data rate lasercom for small satellites. by Faisal A. Fogle. S.M. S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics

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Oulmahdi, Mohamed. "Architecture Autonome et Extensible pour une Couche de Transport Évolutive. Application aux Communications Aéronautique par Satellites." Thesis, Toulouse, INSA, 2017. http://www.theses.fr/2017ISAT0015/document.

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Ces dernières décennies ont été caractérisées par une évolution massive de l'Internet sur tous les plans, couvrant les applications et les technologies réseau. En conséquence, de nouveaux besoins pour les applications et de nouvelles contraintes réseaux apparaissent ; rendant ainsi les protocole (TCP et UDP notamment) de moins en moins efficaces, et plusieurs nouveaux protocoles ont été proposés. Cependant, à cause de plusieurs limites architecturales de la couche Transport, ces nouveaux protocoles n'ont pas été déployés.Partant de ce constat, le travail effectué dans cette thèse porte sur la proposition et la réalisation d'une architecture pour la couche Transport, orientée services et basée composants, dotée de capacités d'extensibilité et d'autoadaptation vis-à-vis des évolutions du contexte applicatif et réseau. La solution proposée repose, d'une part, sur un faible couplage entre les éléments extérieurs (applications et systèmes) et la couche Transport, ainsi qu'entre les composants internes de l'architecture. D'autre part, elle se base sur des modèles et des algorithmes lui permettant de détecter et de prendre en compte les évolutions du réseau ou des applications, et d'adapter son comportement en conséquence. Une implémentation complète de la solution est proposée et testée dans un cadre de communications aéronautiques par satellite. L'objectif étant la gestion de la transition des protocoles spécifique au monde aéronautique vers les protocoles de l'Internet, ainsi que la gestion, au niveau Transport, des liens physiques hétérogènes. Les tests démontrent la faisabilité d'une telle architecture extensible et autonome, les gains en performance qu'il est possible d'obtenir, et les coûts qui en résultent The recent decades are characterized by an important evolution of the Internet at all planes, covering applications and network technologies. This evolution results on new applications requirements and new networks constraints making classical protocols (TCP and UDP typically) less and less suitable. Consequently, many new more efficient protocols have been proposed. However, due to several limitations of the actual Transport layer, these new protocols have not been deployed.From this statement, the work presented in this thesis is about the proposition and the realization of an architecture for the Transport layer, including extensibility and auto-adaptability capabilities regarding the evolution of application and network context. The proposed solution is based on low-coupling between, in a part, the Transport layer and the external actors (applications and systems), and in the other part between the internal component of the architecture. In parallel, the architecture is based on models and algorithms for detecting and taking into account the evolution of networks and applications, and adapt it behavior consequently. A complete implementation of the solution is proposed and evaluated in the context of aeronautical communications by satellite. The aim is the management of the transition phase of the aeronautical network to the Internet protocols suite, and the management of the heterogeneity of the different physical links. The tests demonstrated the feasibility of such extensible and autonomic architecture, the performances gains which can be obtained, and the resulting cost

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Lohmeyer, Whitney Quinne. "Space radiation environment impacts on high power amplifiers and solar cells on-board geostationary communications satellites." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98682.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015. Cataloged from PDF version of thesis. Includes bibliographical references (pages 273-292). Communications satellite operators maintain archives of component telemetry to monitor system function. Operators generally do not typically use the telemetry data for scientific analysis of the space radiation environment effects on component anomalies or performance. We partnered with four geostationary (GEO) operators, acquired >1 million hours of telemetry, and combined these data with space weather observations to investigate relationships between space weather and hardware performance. We focused on the effects of space weather on two component types: solar cells and high power amplifiers. For solar cells, by augmenting >20 years of GEO telemetry with separate GEO space weather measurements, we calculated both on-orbit degradation of Si and GaAs solar cells in an annual average sense, and also quantified the degradation of cells during severe solar proton events (SPEs) of 10 MeV protons > 10,000 pfu. A functional relationship between the amount of degradation and proton fluence is also considered. We used the calculated degradation to evaluate several combinations of space weather environment models with solar cell degradation models and found that predicted performance is within 1% of the observed degradation. These models had not previously been validated using multiple on-orbit GEO datasets. We did not find a model pairing that consistently outperformed the others over all of the datasets. For high power amplifiers, through the use of statistical analysis, simulations, and electron beam experiments we conducted a root-cause analysis of solid state power amplifier (SSPA) anomalies on-board eight GEO satellites. From the statistical analysis, we identified that the occurrence of anomalies was not random with respect to the space weather environment, but that there appeared to be a relationship to high-energy electron fluence for periods of time between 10 - 21 days before the anomalies. From the simulations and electron beam lab tests, we demonstrated that internal charging occurs in the amplifier chain, potentially identifying a cause for the observed anomalies. We substantiated an approach toward understanding space weather effects on space components by obtaining and using long-duration archives of standard commercial telemetry for scientific analysis. The analysis of large telemetry data sets of similar components over long periods of time improves our ability to assess the role of different types of space weather events in causing anomalies and helps to validate models. The findings in this work that relate deep dielectric charging to component anomalies and solar proton events to solar cell degradation make use of only a small fraction of the potentially available commercial geostationary satellite telemetry. Expansion of this work would provide additional insights on the role of space weather to the science community and to the satellite design and operator community. by Whitney Quinne Lohmeyer. Ph. D.

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Deike, William D. "Airborne protected military satellite communications : analysis of open-loop pointing and closed-loop tracking with noisy platform attitude information." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/85767.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2010. Cataloged from PDF version of thesis. Includes bibliographical references (pages 159-162). U.S. military assets' increasing need for secure global communications has led to the design and fabrication of airborne satellite communication terminals that operate under protected security protocol. Protected transmission limits the closed-loop tracking options to eliminate pointing error in the open-loop pointing solution. In an airborne environment, aircraft disturbances and noisy attitude information affect the open-loop pointing performance. This thesis analyzes the open-loop pointing and closed-loop tracking performance in the presence of open-loop pointing error and uncertainty in the received signal to assess hardware options relative to performance requirements. Results from the open-loop analysis demonstrate unexplained harmonics at integer frequencies while the aircraft is banked, azimuth and elevation errors independent of the inertial pointing vector and aircraft's yaw angle, and uncorrelated azimuth and elevation errors for aircraft pitch and roll angles of +/-10° and +/-30°, respectively. Several conclusions are drawn from the closed-loop tracking analysis. The distribution of the average noise power has a stronger influence than the distribution of the received isotropic power on the signal-to-noise ratio distribution. The defined step-tracking algorithm reduces pointing error in the open-loop pointing solution for a pedestal experiencing aircraft disturbances and random errors from the GPS/INS. The rate of performance improvement as a function of the number of hops is independent of the antenna aperture size and the GPS/INS unit. Pointing performance relative to the HPBW is independent of the antenna aperture size and GPS/INS unit for on-boresight, but not for off-boresight. With signal-to-noise ratios averaged over 100 hops and pointing biases less than or equal to 0.5 the half-power beamwidth, the step-tracking algorithm reduces the pointing error to within 0.1 the half-power beamwidth of the boresight, for all tested configurations. The overall system performance is bounded by the open-loop pointing solution, which is based on hardware selection. Closed-loop tracking performance is a function of the number of sampled hops and is for the most part independent of the hardware selection. by William D. Deike. S.M.

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Samuels, Ayanna Terehas. "Assessing the technical, economic and policy-centered feasibility of a proposed satellite communication system for the developing world." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32461.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, Technology and Policy Program, 2005. Includes bibliographical references (p. 213-217). Satellite communication systems remain one of the most under utilized development mediums in less industrialized countries. This research proposes to establish a low cost satellite communications system tailored specifically for the developing world (+/- 30⁰ latitude). The technical, economic and policy related frontiers of the problem are integrated within a MATLAB based satellite communication constellation simulation which is used to assess the feasibility of the proposed satellite system. The analysis demonstrates that with technical advances that would allow higher capacity systems at lower costs and a renewed policy framework in line with the present state of the satellite system industry, it could be feasible to establish a low earth orbit satellite communications system for the developing world. The inputs to the satellite simulation are the proposed system's desired design variables and other relevant parameters. The outputs are system performance, capacity and cost. The Pareto optimal solution trade space is generated by the simulation model using a full-factorial run that probes the entire design space. The application of choice is short messaging services (SMS), chosen for its ability to provide proven connectivity at moderate costs. The capacity and cost of the most ideal Pareto architecture is contrasted against demand in the defined developing world region. The simulation also accounts for the necessary policy considerations and assesses the feasibility of the proposed system amidst the existing industry policy and regulatory framework. Additionally, data regarding the current economic standing of the region and how this forms an underlying basis for the digital divide is presented and assessed. (cont.) The policy and regulatory constraints on the acceleration of telecommunications development throughout the developing world are discussed. This thesis elaborates upon the need for a focus on design for affordability if satellite communication systems are to realize their immense potential for the delivery of needed social services to the world's marginalized. by Ayanna Terehas Samuels. S.M.

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Violet, Michael David. "The development and application of a cost per minute metric for the evaluation of mobile satellite systems in a limited-growth voice communications market." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11148.

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Jaff, Esua K., Muhammad Ali, Prashant Pillai, and Yim Fun Hu. "Satellite mobile multicast for aeronautical communication." 2014. http://hdl.handle.net/10454/10653.

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No Satellite communication with its world-wide coverage has now become an indispensable part of the Aeronautical communication. Support for high-speed Internet access by the new generation satellite systems has made the provision of IP-based multimedia applications on-board the aircraft possible at all times. Considering the expensive nature of satellite resources, IP multicast can provide a cost-effective and bandwidth saving means of delivering real-time group communication and streaming media to air passengers and crew during a flight. In IP multicast communication, traffic from the source travels along the established multicast tree to reach all group members. For mobile receivers like the aircraft which may move from one satellite beam to another, then special techniques are required to ensure that a branch of the multicast tree follows the mobile receiver into the target beam. This paper proposes a novel technique based on the Proxy Mobile IPv6 (PMIPv6) protocol to support IP multicast receiver mobility over satellite networks for an aircraft as it moves and changes its point of attachment from one satellite gateway (GW) to another. Performance evaluation shows that the proposed scheme is better than the Mobile IPv6-based approach in terms of GW handover (GWH) latency and number of packets lost during GWH.

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Cheng, Yongqiang, Kai J. Xu, Anju Pillai, et al. "A realization of integrated satellite-terrestrial communication networks for aeronautical services via joint radio resource management." 2013. http://hdl.handle.net/10454/9637.

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Despite air travel has not grown as predicted, air travel is still expected to rise to just less than doubling the current figure by 2030. This creates an urging need to develop more efficient Air Traffic Management (ATM) solutions. Around the globe, research and development initiatives have been launched to modernize the air traffic control infrastructures. These modernized infrastructures will be built around continuous information gathering, sharing and transferring of data between aircraft and air navigation service providers and airports ground infrastructure, which will be difficult for current aeronautical communications systems to handle. As a result, new communication infrastructures are required to manage future aeronautical communication traffic demand. This paper proposes an integrated aeronautical communication architecture consisting of four radio access technologies for communications between aircrafts and ground Aeronautical Telecommunication Network (ATN). The design and implementation of a Joint Radio Resource Management (JRRM) framework to manage these radio resources are discussed. The design is verified by a proof-of-concept JRRM prototype which is developed for the management of radio resource between the Inmarsat Broadband Global Area Network (BGAN) and the Aeronautical Mobile Airport Communication System (AeroMACS).

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Cheng, Yongqiang, Kai J. Xu, and Yim Fun Hu. "A redundancy software design for joint radio resource management system in a satellite-terrestrial based aeronautical communication network." 2013. http://hdl.handle.net/10454/9636.

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No This paper presents a Master/Slave redundancy mechanism for the airborne Integrated Modular Radio to improve the reliability of the joint radio resource management (JRRM) system. The proposed mechanism adopts keep-alive heart beat messages and real time information synchronization to ensure a smooth switchover in the event of a platform failure. To enhance the scalability and decoupling of the system, the proposed hot swap solution makes the JRRM switchover transparent to both the higher layers and the lower layers. The experiment results and the performance obtained from the test-bed has proved the validity of the solution.

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Hu, Yim Fun, Matthias Holzbock, A. Jahn, and M. Werner. "Advances of Aeronautical Communications in the EU Framework." 2009. http://hdl.handle.net/10454/2635.

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No This paper reports on the advancement in the research and development of aeronautical satellite communications within the EU framework. Starting from key aspects such as spectrum regulatory and marketing issues which affect the development of aeronautical communication systems, discussion on the motivation behind the two EU projects, ABATE and WirelessCabin and their interconnection then follows. ABATE concentrated on the development of an aeronautical communications system for flight routes in the European and Northern Atlantic regions. The enabling technology considered in ABATE is discussed. Major achievements and results obtained in the project are reported in this paper. These include the development of a powerful software tool based on a logical design methodology for aeronautical satellite communication systems as well as the characterization of the aeronautical channel through a series of channel measurement campaign and a demonstration of in-flight multimedia satellite communication. The evolvement from ABATE to WirelessCabin is then highlighted. The main objective and current development of WirelessCabin since the start of the project are presented. In particular, issues on electromagnetic compatibility between different electronic equipments on board the aircraft cabin are discussed. Networking aspects for mobility, QoS and VPN support are studied. Specifically, different scenarios for the location management and address assignment schemes for mobility and VPN support are discussed in detail.

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Jaff, Esua K., Misfa Susanto, Muhammad Ali, Prashant Pillai, and Yim Fun Hu. "Network coding for multicast communications over satellite networks." 2015. http://hdl.handle.net/10454/11128.

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No Random packet errors and erasures are common in satellite communications. These types of packet losses could become significant in mobile satellite scenarios like satellite-based aeronautical communications where mobility at very high speeds is a routine. The current adaptive coding and modulation (ACM) schemes used in new satellite systems like the DVBRCS2 might offer some solutions to the problems posed by random packet errors but very little or no solution to the problems of packet erasures where packets are completely lost in transmission. The use of the current ACM schemes to combat packet losses in a high random packet errors and erasures environment like the satellite-based aeronautical communications will result in very low throughput. Network coding (NC) has proved to significantly improve throughput and thus saves bandwidth resources in such an environment. This paper focuses on establishing how in random linear network coding (RLNC) the satellite bandwidth utilization is affected by changing values of the generation size, rate of packet loss and number of receivers in a satellite-based aeronautical reliable IP multicast communication. From the simulation results, it shows that the bandwidth utilization generally increases with increasing generation size, rate of packet loss and number of receivers.

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Dissertations / Theses on the topic 'Aeronautical satellite communication'

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