Academic literature on the topic 'Aeronautical satellite communication'

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<br>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

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.

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.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 113-125).<br>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.<br>by Kathleen Michelle Riesing.<br>Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 115-124).<br>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.<br>by Ryan W. Kingsbury.<br>Ph. D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 175-181).<br>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.<br>by Hyosang Yoon.<br>Ph. D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2013.<br>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.<br>Cataloged from department-submitted PDF version of thesis.<br>Includes bibliographical references (p. 86-89).<br>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.<br>by Whitney Quinne Lohmeyer.<br>S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005.<br>Includes bibliographical references (p. 159-165).<br>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.<br>(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.<br>by Jennifer E. Underwood.<br>S.M.