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This article describes the architecture of two broadband satellite communication systems using a Very Small Aperture Terminal which have been installed on two Spanish oceanographic research vessels. The potential use, equipment and their characteristics are studied and compared. Analysing four parameters (jitter, round time trip, package loss and throughput), system configuration has been modified from the launch until the final optimization in order to improve TCP/IP based communications. The hardware selection is fundamental to the successful implantation of the systems, which has to guarantee the quality of satellite services. Satellite channels can affect TCP/IP protocols, but these difficulties were overcome with correct system configuration. Despite the service being operated correctly, several tests had to be done periodically to improve it and check the satellite service conditions. After the optimization of equipment configuration and network parameters on VSAT links of both vessels, effective and stable links have been obtained for web navigation and VPN communication.

The objective of the present study is to hold a preliminary analysis and design of a lunar global satellite navigation system able to provide accurate positional information to operators on the surface or in low lunar orbits. The outcome is a set of indications concerning the implications inherent in such a system. This set of indications consists in the main objectives, requirements and constraints needed during the definition and implementation of an infrastructure for global precise positioning on the lunar surface. In any preliminary mission analysis it is important to determine the design drivers. In our case, the main drivers are the orbital height, the number of satellites in the constellation, the orbital inclination and the number of orbital planes. These four parameters are the main characteristics that define the constellation performance, therefore their final selection is crucial for the mission success. In our case, two constraints have been applied in order to determine the constellation: (1) no more than three orbital planes and (2) no more than 18 satellites. The constellation selection process has been carried out with the help of computer simulation. Thanks to it, we were able to choose the constellation whose parameters combination resulted in the best performance. The final constellation has a height of 6500 km, three orbital planes, 15 satellites and an inclination of 90°. In order to maintain the correct performance of the constellation, a station-keeping strategy has been developed. Computer simulation of the chosen constellation allowed us to quantify the perturbation effects on the satellites and to identify which perturbation is the primary source of orbital deviations. Central body gravitation, third body-perturbations and solar radiation pressure have been computed for a period of one year with the result of a propellant (also known as Δv) budget of 1 km/s. Payload selection is an important step in the design process. The characterization of its mass, power and thermal requirements, and components influences the design of all the other subsystems. Relativistic effects on time are taken into account because the accuracy of the system depends on clock errors. The study concludes that, although relativistic effects on time are less significant on the constellation than on the terrestrial GPS system, they still need to be corrected. This study also undertakes a preliminary design of the satellite subsystems. Power and mass budget are made and a preliminary analysis of the propulsion, thermal and communications subsystems are also carried out. The proposed preliminary satellite design consists in a 1000kg-1600W class platform which will transmit in the L-band (to the lunar surface) and in the X-band (to the Earth). If the station-keeping is carried out by a bipropellant thruster, the propellant budget needed is 225 kg. However, some indications for electrical propulsion for the station-keeping maneuvers are also provided. The thermal environment is the biggest challenge of the mission because of the Earth eclipses1. They can last more than 5 hours which leads to the temperature getting as low as -35°C. During lunar2 eclipses, secondary batteries can produce around 1300 W which will probably not be sufficient to maintain the spacecraft temperature within operational limits during Earth eclipses, so an extra set of batteries will be needed.

Satellite remote sensing imagery represents an attractive data source to monitor large regions with frequent updates. In this context, the operational production of accurate land cover maps plays an important role in global-scale environmental assessments and becomes crucial for a wide range of research domains. New earth observation missions such as Sentinel provide images with high spatial and temporal resolution. Accordingly, new image classification methods for the generation of reliable land cover maps are needed. In the framework of the Sentinels Synergy for Agriculture (SENSAGRI) project at \textit Centre d'Études Spatial de la Biosphere (CESBIO) in Toulouse (France), this work aims to describe new schemes for detecting crop areas along the agricultural season. The research has focused on performing statistical fusion at decision-level to combine classification results in order to exploit the synergies between Sentinel-1 and Sentinel-2 image times series.

Global Navigation Satellite Systems (GNSS) opportunity signals reflected at or near the Earth's surface have already shown their potential to perform retrievals of a number of geophysical parameters. Radio occultations using GNSS signals are also used for atmospheric sensing. This letter presents a GNSS technique to retrieve vegetation water content (VWC). This technique measures the received powers of the GPS signals in open sky and under the vegetation layer. From these two powers, the attenuation due to the vegetation is computed, which is related to the VWC. This letter presents the results obtained after deploying the instrument in a walnut-tree stand for 11 months.

This project presents the design of a solar sail as a feasible solution to thrust nanosatellites. A solar sail is a high-energy space propulsion system that uses solar radiation pressure to push large ultra-thin mirror to high speed, enabling the combination of low-cost operations with long operating lifetimes. In this project, the Solar Sail Module (SSM) is designed to be packed into a Plug and Play (PnP) module of 2U size (20cm x 10cm x 10cm). The solar sail is aimed for cubesats performing missions orbiting the Moon. Basically, the sail is sized for a trajectory that departs from GEO, follows a spiral to escape from the Earth and finally drives the nanosatellite to the target lunar orbit. The SSM detailed design has been done using Commercial Off-The-Shelf (COTS) components. The overall design of the SSM is presented by a CAD design done in CATIAv5. With respect to the trajectory calculation, a 4 body problem is implemented through a self-developed Matlab® code with RKF7 integrator. The trajectory calculation enables the validation of the SSM design to propel spacecraft up to 8kg in less than 3.6 years to the vicinity of the Moon. The main contribution of this work is to provide the nanosatellites community with a feasible PnP SSM that can drive this kind of satellites from the Earth to the Moon

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The space industry is currently witnessing two concurrent trends: the increased modularity and miniaturization of technologies and the deployment of constellations of distributed satellite systems. As a consequence of the first trend, the relevance of small satellites in line with the “cheaper and faster” philosophy is increasing. The second one opens up completely new horizons by enabling the design of architectures aimed at improving the performance, reliability, and efficiency of current and future space missions. The EU H2020 ONION project (“Operational Network of Individual Observation Nodes”) has leveraged on the concept of Fractionated and Federated Satellite Systems (FFSS) to develop and design innovative mission architectures resulting in a competitive advantage for European Earth Observation (EO) systems. Starting from the analysis of emerging needs in the European EO market, the solutions to meet these needs are identified and characterized by exploring FFSS. In analogy with terrestrial networks, these systems envision the distribution of satellite functionalities amongst multiple cooperating spacecrafts (nodes of a network), possibly independent, and flying on different orbits. FFSS are considered by many as the future of spacebased infrastructures, as they offer a pragmatic, progressive, and scalable approach to improve existing and future space missions. This work summarizes the main results of the ONION project and the high-level design of the Marine Weather Forecast mission for polar regions.

Nowadays GNSS1 enhancement techniques have reached a relevant impor- tance and are present in a wide variety of applications. During the last years the Research Group of Astronomy and Geomatics (gAGE) from the Tech- nical University of Catalonia (UPC) has developed and tested new satellite navigation techniques which allow the extension of local services based on the real-time carrier phase ambiguity resolution2 to wide area scale (i.e., base- lines between the rover and reference stations greater than 100 km instead of 10 or 20 km as in common DGPS), for both dual-frequency (GPS) and tri-frequency systems (Galileo and Modernized GPS). These are the so-called Wide Area Real Time Kinematic techniques for 2 and 3 frequencies-systems (WARTK-2 and WARTK-3, respectively, see Colombo et al. 1999, 2002 and Hernandez-Pajares et al. 2003 that are based on an optimal combination of accurate ionospheric and geodetic models, in a permanent reference stations network. This Master Thesis touches on two important aspects about WARTK: one regards the broadcasting technique for the WARTK correction messages, and the feasibility of using RTCM 3.1 standard; and the other consists of a real-time implementation of the current WARTK-CPF3 software.

Satellite networks are expected to become an integral part of upcoming 5G systems. In this regard, the adoption of 5G mainstream softwarisation technologies such as Software Defined Networking (SDN) and Network Function Virtualization (NFV) arises as a necessary step in the evolution of satellite ground segment systems (e.g. satellite gateways and terminals). This softwarisation would allow satellite communications services to be delivered in a more flexible, agile and cost-effective manner than done today. The applicability of NFV and SDN technologies in the satellite ground segment has been researched by H2020 VITAL project in the context of combined terrestrial-satellite networks. This extended abstract outlines the scope of two case studies from VITAL project outcomes that will be presented at WWRF39.

Primero se realizó el diseño teórico de la antena; en la construcción de ésta, se uso un analizador de antenas. [ANGLÈS] This project aims to design and implementation of a quadrifilar helical antenna to optimize the performance of a receiving station. When we refer to optimizing, we talk about to receive images with maximum coverage as possible, which is possible with an antenna that is as omnidirectional. This project is structured with a tutorial on the project context, which talks about low polar orbit satellites, its operation, as these transmit images and how to receive these images on a receiving station. Then we focus on the design and construction of quadrifilar antenna. Where first there will be a theoretical analysis of the antenna, followed by a test antenna design using a simulator. Secondly, we proceed to the construction of the antenna, then measurements are taken of the antenna with the aid of an antenna analyzer to verify that the antenna characteristics are equal to the previously you miss in the theoretical analysis. Finally, we install the antenna in the receiving station and it starts to receive images. Finally we analyze the results of the received images and makes some recommendations for future applications. [CASTELLÀ] Este proyecto tiene la finalidad el diseño y la realización de una antena cuadrifilar helicoidal que optimice el comportamiento de una estación receptora. Con optimizar nos referimos a recepcionar imágenes con la máxima cobertura posible, lo cual será posible con una antena que sea lo más omnidireccional. Este proyecto esta estructurado con un tutorial acerca del contexto del proyecto, el cual habla acerca de satélites de orbita polar baja, su funcionamiento, como estos transmiten imágenes y como recibir estas imágenes en una estación receptora. Luego nos centraremos en el diseño y la construcción de la antena cuadrifilar. Donde primero, se hará un análisis teórico de la antena; seguido de unas pruebas del diseño de la antena con ayuda de un simulador. En segundo lugar, se procede a la construcción de la antena; luego se realizan mediciones de la antena con la ayuda de un analizador de antenas para comprobar que las características de la antena sean iguales a las echas previamente en el análisis teórico. Por ultimo, se instala la antena en la estación receptora y se reciben las imágenes. Por último se hace un análisis de los resultados de las imágenes recibidas y se hacen algunas recomendaciones para futuras aplicaciones. [CATALÀ] Aquest projecte té com a finalitat el disseny i la realització d'una antena cuadrifilar helicoïdal que optimitzi el comportament d'una estació receptora. Quan parlem d'optimitzar ens referim a recepcionar imatges amb la màxima cobertura possible, la qual cosa serà possible amb una antena que sigui el més omnidireccional possible. Aquest projecte està estructurat amb un tutorial sobre el context general del projecte, el qual parla sobre satèl·lits d'òrbita polar baixa, com transmeten imatges i com rebem aquestes imatges en una estació receptora. Després ens centrarem en el disseny i la construcció de l'antena cuadrifilar. On primer, es farà una anàlisi teòric de l'antena, seguit d'unes proves del disseny de l'antena mitjançant un simulador. En segon lloc, es procedeix a la construcció de l'antena, després es realitzen mesures de l'antena amb l'ajuda d'un analitzador d'antenes per comprovar que les característiques de l'antena siguin iguals a les prèviament obtingudes en l'anàlisi teòric. Finalment, s'instal·la l'antena a l'estació receptora i es reben les imatges. Per últim es fa un anàlisi dels resultats de les imatges rebudes i es fan algunes recomanacions per a futures aplicacions.

This paper deals with the problem of precoding in multibeam satellite system with rate splitting (RS). In contrast to the single-stream (SS) case where a unique private frame is transmitted towards each beam, in RS we consider the simultaneous transmission of a public frame to all intended users superimposed with each private frames. In this context, every user terminal (UT) firstly decodes the public frame which contains data from all UTs at all beams and; posteriorly, its intended private frame which is only decodable by a set of users. With this, each UT receives information from both the public and the private frame, leading to a system sum-rate increase in some cases. This performance increase is evaluated by computing an upper bound of the attainable rates. Moreover, a low-complexity precoding alternative is proposed considering a decoupled design of the precoding of the private frames and public frames. This technique is evaluated considering a real multibeam satellite system. A substantial gain with respect to the current benchmark technique is identified., Grant numbers : This work has received funding from the Spanish Ministry of Economy and Competitiveness (Ministerio de Economia y Competitividad) under project TEC2014-59255-C3-1-R (ELISA). © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

©2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. In the past decade Global Navigation Satellites System Reflectometry (GNSS-R) has emerged as a new technique for earth remote sensing for various applications, such as ocean altimetry and sea state monitoring. After the success of the GNSS-R demonstrator payloads aboard the UK-DMC or TDS-1 satellites; at present, there are several missions planned to carry GNSS reflectometers. The GNSS rEflectometry, Radio Occultation, and Scatterometry onboard International Space Station (GEROS-ISS) is an innovative ISS experiment exploiting GNSS-R technique to measure key parameters of ocean, land, and ice surfaces. For GEROS-ISS mission, the European Space Agency (ESA) supported the study of GNSS-R assessment of requirements and consolidation of retrieval algorithms (GARCA). For this, it was required to accurately simulate the GEROS-ISS measurements including the whole range of parameters affecting the observation conditions and the instrument, which is called GEROS-SIM. To meet these requirements, the PAU/PARIS end-to-end performance simulator (P$^{2}$EPS) previously developed by UPC BarcelonaTech was used as the baseline building blocks for the level 1 (L1) processor of GEROS-SIM. P$^{2}$EPS is a flexible tool, and is capable of systematically simulating the GNSS-R observations for spaceborne GNSS-R missions. Thanks to the completeness and flexibility, the instrument-to-L1 data module of GEROS-SIM could be implemented by proper modification and update of P$^{2}$EPS. The developed GEROS-SIM was verified and validated in the GARCA study as comparing to the TDS-1 measurements. This paper presents the design, implementation, and results of the GEROS-SIM L1 module in a generic way to be applied to GNSS-R instruments.

3Cat-3 is a nanosatellite based on the 6 unit cubesat standard. Its payload is an optical multispectral imager that imposes stringent downlink requirements for a nanosatellite. This TFG is based on the experience gained in 3Cat-1 and 3Cat-2 communications systems to develop a "high speed" (goal >= 5 Mbps) downlink for nanosatellites based on the TI CC3200. In order to accomplish the objectives of the next generation of nanosatellites high-speed downlinks have to be designed. This goal faces stringent design constraints as nanosatellites are limit in power, processing capabilities and dimensions. In the quest for higher bit rates the widely used VHF band has to be replaced for higher frequency bands and the link budged margin tightened, decreasing the SNR at reception. The proposed solution uses COTS 2.4 GHz WiFi adapters as transceivers. Range limitations imposed by the default 802.11 mode of operation are bypassed by using packet forging and injection at transmission jointly with monitor mode at reception. A loss-resilient unidirectional downlink is achieved by using application-layer encoding by means of LPDC-Staircase codes. This solution has been already implemented in 3CAT-2, a 6 unit cubesat GNSS-R mission to be launched in July 2016. In addition, bursts of errors are combated by using Reed-Solomon. The system has been tested under Doppler shift and scintillation effects, and a 188Km link between Barcelona and Mallorca has been performed, showing satisfactory results.

The GNSS rEflectometry, Radio Occultation and Scatterometry onboard the International Space Station (GEROS-ISS) experiment consists of the installation of a GNSS reflectometry (GNSS-R) instrument on the International Space Station (ISS). Due to the complex structure of ISS, the GEROS-ISS instrument suffers from multipath effects. The collected signals are not only from received directly, but also after multiple reflections in the ISS structure. This work analyzes the multipath effect of the GEROS-ISS instrument based on the ISS structure. Using the ray tracing simulation, all rays reaching the instrument after one or two reflections are computed, as well as the corresponding additional delays. This information, together with the direction of arrival to the antenna arrays (up and down-looking), and the co- and cross-polar antenna patterns is used to assess the impact of multipath on the waveforms are demonstrated.

Descripción de la historia, situación actual y futuro de los CubeSats. Diseño e implementación de un transceptor y antenas de un CubeSat y otros módulos secundarios. [ANGLÈS] CubeSat transmission system development: antenna adaptation, BALUN and transceiver. Also includes a crystal LCD shutter control system development. [CASTELLÀ] Desarrollo del sistema de transmisión de un CubeSat: adaptación de antenas, BALUN y transceptor. También se incluye el desarrollo del sistema de control de un obturador basado en un cristal LCD. [CATALÀ] Desenvolupament del sistema de transmissió d'un CubeSat: adaptació de les antenes, BALUN i transceptor. A més, inclou el desenvolupament del sistema de control d'un obturador basat en un cristall LCD.

Projecte realitzat en col·laboració amb l’empresa TriaGnoSys GmbH [ANGLÈS] In certain situations the operation of mobile operator infrastructure can be affected by natural disasters such as hurricanes, fires or earthquakes. This fact hinders optimum coordination of rescue actions and communication between field teams and its respective control centers. In order to solve the above problem, it has been created the ABSOLUTE project. This involves the deployment of a UMTS/LTE/Wi-Fi/D2D communications system with access to outer networks through a satellite link. In this document are analyzed different techniques to optimize HTTP/HTTPS traffic when utilities for emergency situations as Google Public Alerts, Google Crisis Maps, Crowdmap or Twitter, are accessed by the rescue personnel. [CASTELLÀ] En determinadas situaciones la operatividad de la infraestructura del operador móvil puede verse afectada por desastres naturales como huracanes, incendios o terremotos por ejemplo. Este hecho imposibilita la óptima coordinación de las labores de rescate y la comunicación entre los equipos de campo y los centros de control respectivos. Con el propósito de solventar el problema expuesto, se ha creado el proyecto ABSOLUTE. Éste consiste en el despliegue de un sistema de comunicaciones UMTS/LTE/Wi-Fi/D2D con acceso a redes exteriores a través de un enlace por satélite. En este documento se proponen diferentes técnicas de optimización de tráfico HTTP/HTTPS cuando utilidades web para situaciones de emergencia como Google Public Alerts, Google Crisis Maps, Crowdmap o Twitter, son accedidas por los equipos de rescate. [CATALÀ] En determinades situacions l'operativitat de la infraestructura de l'operador mòbil es pot veure afectada per desastres naturals com huracans, incendis o terratrèmols. Aquest fet impossibilita l'òptima coordinació de les tasques de rescat i la comunicació entre els equips de camp i els centres de control respectius. Amb el propòsit de resoldre el problema exposat, s'ha creat el projecte ABSOLUTE. Aquest consisteix en el desplegament d'un sistema de comunicacions UMTS/LTE/Wi-Fi/D2D amb accés a xarxes exteriors mitjançant un enllaç per satèl·lit. En aquest document es proposen diferents tècniques d'optimització de tràfic HTTP/HTTPS quan utilitats web per a situacions d'emergència com Google Public Alerts, Google Crisis Maps, Crowdmap o Twitter, són accedides pels equips de rescat.

Projecte final de carrera reaitzat en col.laboració amb La Sapienza Although the Cassini-Huygens interplanetary mission is a project that covers Saturn, its rings and most of its multiple satellites, in this introduction attention will be focused mainly in the biggest moon of Saturn: Titan, since Cassini Radar, from which Cassini Processing Altimetric Data (PAD) system (on which is based this work) receives science data, has been built especially to study Titan.

Implementation of a UHF transceiver for the ³Cat-1 satellite ground station and development of a graphical environment to send telecommands to the satellite and receive and decode the satellite telemetry.

Projecte realitzat en col.laboració amb Technische Universität Berlin The purpose of this research is to design an antenna suitable for satellite communications. This antenna will be a patch antenna to take advantage of its size, weight and price characteristics. As innovation, a coupled patch will be added, taking as reference the research in [8] and [9]. Those two papers will be, however, only a starting point, since our requirements are completely different. The antenna design will have three phases, in which the objectives will be progressively fulfilled. The first phase will consist in taking the idea seen in [8] and [9] and adapt it to our working band. In the second phase circular polarization will be achieved. And finally, in the third phase we will end the antenna design with the gain and radiation diagram. The text is divided in five chapters. The first one introduces the patch antennas and the satellite communications from a general point of view. The second chapter explains the patch antenna theory needed to understand the research done, beginning with physical characteristics and finishing with antenna arrays theory. The third chapter introduces and explains the parameters that will be simulated while designing the antenna, that we will use to decide whether the results are good or bad. The fourth chapter has the antenna research, using all the ideas exposed in the previous chapters. Finally, the fifth chapter summarizes all the work done. There are three appendixes. The first one introduces an alternative antenna design with different purposes from the main research. The second appendix shows the hardware and software used during the simulations. And the third one explains the coordinate system used along the work to represent the results. Satellite communications and patch antennas are introduced below.

Land use and land cover information are key information for Governments in developing countries. In this context, remote sensing satellites like Landsat or SPOT can provide valuable data covering several decades. We have developed a methodology to generate land cover maps with the aim to analyze changes in the last 25 years in the NW region of Senegal. In particular, we have applied the radiometric and atmospheric corrections prior to the classification algorithm or to the generation of vegetation indexes and, finally, to analyze the spatial and temporal variability, post-classification change detection techniques have been applied, providing valuable quantitative information.

El presente trabajo final de carrera consiste en implementar y verificar algunos de los subsistemas que forman la misión Lunar diseñada por el equipo Team FREDNET con motivo del Google Lunar X Prize. Uno de los proyectistas se encargará de los subsistemas del Rover Lunar y el otro se encargará de los subsistemas del Lunar Lander. Debido a que hay multiples subsistemas es posible que haya un tercer proyectista. Este proyecto se realiza en colaboración con otros investigadores de múltiples nacionalidades por lo que requiere formar parte del grupo en un proyecto real de exploración lunar. Este proyecto incluye habilidades de trabajo en equipo, preparación de resultados, toma de decisiones, etc. REQUISITOS: - Estar terminando la carrera técnica de Sistemas, Telemática o Aeronáutica (Obligatorio) - Disponibilidad horaria y presencial (Obligatorio) - Tener conocimientos en buses y radio-enlaces (Deseable) - Manejo de sistema operativo WINDOWS y LINUX (Deseable)

This study is addressed to the control system of a mini-launcher. A reaction control based on purge pressure from a solid propellant engine of a main stage, or using cold gas from a storage tank will be the control method. Pulse modulator system will be the actuation method studied, and simulations about its suitability will be done with Simulink. In this thesis, we try to check if this method is able to be implemented in a low cost way the Wiki-Launcher, a mini-launcher less than 100 kg. At the time we try to check if the control allowed by the reaction control can manage all the phases of the flight. Both possible control configurations are going to be analyzed.

Este proyecto ha sido desarrollado para Indra Espacio en el marco del desarrollo del prototipo de un sistema GBAS. El proyecto principal está dividido en dos grandes bloques: el segmento de la estación de referencia y el segmento del usuario. Este proyecto se enfoca únicamente en el segundo bloque: el segmento de usuario. Los objetivos fijados para el trabajo han sido la creación de un software capaz de realizar el post-procesado de los datos GPS recibidos por un receptor y almacenados en ficheros RINEX (formato estándar para el almacenamiento de datos GPS) obteniendo la posición del receptor. Posteriormente, después de la validación del código, se aplicarán las correcciones proporcionadas por una estación de referencia. Finalmente se comprobará su funcionamiento con un RINEX móvil gracias a la recogida de datos que realizamos personalmente. El trabajo ha sido dividido en cuatro capítulos. El primero pretende explicar todos los aspectos teóricos en los que se basan los sistemas GPS/DGPS. En el siguiente capítulo se realiza una descripción esquemática del algoritmo desarrollado. En el tercer capítulo se explica el funcionamiento de la interfaz gráfica diseñada para la aplicación del código. Y finalmente se mostrarán los datos obtenidos con el software diseñado Este proyecto ha sido desarrollado para Indra Espacio en el marco del desarrollo del prototipo de un sistema GBAS. El proyecto principal está dividido en dos grandes bloques: el segmento de la estación de referencia y el segmento del usuario. Este proyecto se enfoca únicamente en el segundo bloque: el segmento de usuario. Los objetivos fijados para el trabajo han sido la creación de un software capaz de realizar el post-procesado de los datos GPS recibidos por un receptor y almacenados en ficheros RINEX (formato estándar para el almacenamiento de datos GPS) obteniendo la posición del receptor. Posteriormente, después de la validación del código, se aplicarán las correcciones proporcionadas por una estación de referencia. Finalmente se comprobará su funcionamiento con un RINEX móvil gracias a la recogida de datos que realizamos personalmente. El trabajo ha sido dividido en cuatro capítulos. El primero pretende explicar todos los aspectos teóricos en los que se basan los sistemas GPS/DGPS. En el siguiente capítulo se realiza una descripción esquemática del algoritmo desarrollado. En el tercer capítulo se explica el funcionamiento de la interfaz gráfica diseñada para la aplicación del código. Y finalmente se mostrarán los datos obtenidos con el software diseñado

Aquest projecte va encarat a donar solució tècnica al problema de la incomunicació de diferents wilayes (agrupacions de refugiats semblants a pobles) situades a la part occidental del desert algerí, molt a prop de la frontera entre Algèria i el territori ocupat i a alguns pobles de la zona dels territoris alliberats del Sàhara Occidental, tocant a Mauritània. En un principi el projecte estava encarat a realitzar una única instal·lació a una de les wilayes. A mesura que es va anar avançant, la contrapart va estar molt interessada en ampliar els punts de connexió i donar cobertura a altres zones. Les wilayes a les que finalment ha anat destinat aquest projecte són: Dajla i Smara i els pobles: Tifariti, Meharrize, Bir Lehou, Mijek, Aguenit i Dougaj. Les comunicacions són un dels principals eixos sobre els quals gira el desenvolupament actual. La millora dels sistemes de comunicació existents als campaments és un aspecte primordial pel seu correcte desenvolupament. En aquests moments el servei telefònic és, en molts casos, inexistent o molt precari. Amb aquest projecte, s’ofereix una millora substancial ja que per telefonia VoIP via satèl·lit no hi ha els problemes de col·lapse habituals que hi ha per una línia única via Algèria. D’altra banda es dóna la possibilitat de connexió a Internet. El treball doncs, ha consistit en l’anàlisi del problema, la realització d’un estudi de la problemàtica, un disseny de les solucions tecnològiques adequades, la tria de les tecnologies més adients, l’adquisició de la subvenció i dels equips corresponents i la implementació del sistema sobre el terreny.

During the last years the space has been populated by Distributed Satellite Systems, which some of them have started to implement Inter-Satellite Communication. However, current solutions are composed of a unique mission and homogeneous spacecrafts or a combination of them. This actually limits their use in the so-called “Federated Satellite Systems” that proposes the interconnection of heterogeneous spacecrafts in order to establish a mission collaboration whenever the resources are not used for the primary mission goal. This point-to-point proposal has some limitations that can be addressed in a multi-hop platform, i.e. a network. Current satellite network proposals, such as Space Internet or Heterogeneous Spacecraft Network, propose the creation of a common network backbone which provides connectivity for future missions. However, this approach supposes huge maintenance and deployment costs. This work presents a new interconnected space paradigm based on a more peer-to-peer architecture: Internet of Satellites. This new paradigm promotes the creation of sporadic networks, called Inter Satellite Networks, which provide the required communication means to deploy Federated Satellite Systems for multi-hop cases.

This Final degree's thesis is done under the UPC-Canadà program in which the author realizes his last degree year in Montréal, Canada, to the Polytechnique de Montréal university under the supervision of Dr. Giovanni Beltrame being part of his laboratory Mistlab and also on the Polyorbite group of students. Polyorbite is an organization that participates in the biannual contest CSDC (Canadian Satellite Design Challenge) that consists on the realization from 0 of a 3U CubeSat by undergraduate and master students. By the start of this thesis on September 2016, the contest was in the middle of the 2014-2016 iteration without having almost nothing on the telecommunication part, having just 2 semesters for design, build and test an entirely telecommunications system, suitable for the satellite purpose, until June 2016 in which the final presentations of the contest took place on Ottawa. The purpose of this thesis is then an early design of a telecommunications system for a CubeSat satellite.

This paper analyzes frequency packing schemes applied to multibeam satellite systems. In order to simulate a realistic scenario we have taken into account the presence of co-channel interference and spectrum limitations. The results show that with low order modulations, e.g. QPSK and 8APSK, the frequency packing schemes outperform in terms of spectral eciency conventional single carrier schemes with high modulation orders up to 32APSK. However, the experimental validation carried out with the DVB-S2 modulation and coding (ModCod) schemes reveals that there is a gap between the maximum achievable rates and the throughput. This result highlights that new ModCod schemes have to be designed, so that frequency packing schemes perform closer to the theoretical bounds.

We study the applicability of soft interference cancelation in the forward link of multibeam satellite systems with focus on mobile terminals. We adopt a standard currently used in commercial satellite systems as a reference. The multibeam satellite antenna radiation diagram has been generated using a physical optics re¿ector model while a widely adopted channel model has been used for the land mobile satellite channel. The interference pattern has been derived using a system simulator developed by the European Space Agency. Starting from the analysis of the interference pattern, we study the application of a low-complexity soft interference cancelation scheme for commercial applications. Our results show that, under realistic conditions, a two-colors frequency reuse scheme can be employed while guaranteeing service availability across the coverage and keeping the complexity at the user terminals relatively low.

La idea principal de este proyecto es ofrecer servicios a los alumnos de la universidad UPC. Los alumnos accederán a estos servicios a través de una aplicación para dispositivos móviles. La UPC está formada por diversos campus, situados en localidades diferentes, y cada uno de ellos dispondrá de sus propios servidores. Para seleccionar el campus al cual el alumno se conectará, se hará uso de la tecnología GPS. El alumno accederá directamente al servidor que se encuentre más próximo a su posición. De esta manera se pretende conseguir que el tiempo de retardo entre el dispositivo y el servidor sea mínimo. El servicio ofrecido es un podcast. Este servicio tiene la finalidad de permitir a los alumnos acceder al material docente ofrecido por la universidad, como por ejemplo, documentación en formato PDF de las asignaturas, colecciones de problemas y ejercicios, etc. Para el desarrollo de este proyecto ha sido necesario el estudio de la tecnología Microsoft .NET. Esta tecnología ofrece un entorno de desarrollo que permite la programación de aplicaciones para dispositivos móviles, así como la implementación de servicios Web. También se ha requerido el estudio de otros ámbitos que intervienen en este proyecto, como son los servidores Web y las bases de datos. Este proyecto hace uso de servidores Web para la publicación tanto de los podcast, como de las páginas y los servicios Web. También ha sido necesario el uso de una base de datos para almacenar información sobre los campus, los servidores y los podcast. Finalmente se ha conseguido implementar una aplicación para dispositivos móviles capaz de recibir e interpretar la señal GPS, así como gestionar, descargar y reproducir archivos de podcast. Además esta aplicación hace uso de servicios Web para tratar con la información de la base de datos.

This paper will cover a variety of topics. First, it will overview the concepts of GRACE and GOCE satellite missions. Second, it will summarise some results of the assessment of the recent Earth global gravity field models, focusing on the study of the differences between satellite altimetry and tide gauge observations. Third, it will describe the computation and evaluation of a new geoid model for the Western Mediterranean area in the near future. All three topics will be set in the framework of the existing data and how airborne gravimetry can contribute. With the increased interest in coastal zone mapping because of threats like sea level change, airborne gravimetry can bridge the gap between land and satellite-altimeter-derived gravity data. As such, a proposal will be made to collect airborne gravimetry in key Mediterranean coastal zones.

[ANGLÈS] The aim of the thesis is to provide a simplified basic framework for the implementation of GNSS/INS integration using SDR receiver. This thesis investigates the different architectures of integration between the inertial navigation system and the GNSS receiver and the advantages and disadvantages of each. The integration is implemented in MATLAB using simulated GPS and inertial sensor data. [CASTELLÀ] El objetivo de la tesis es proporcionar un marco simplificado para la implementación básica de la integración del GNSS/INS utilizando Software Defined receptor de radio. Esta tesis investiga las diferentes arquitecturas de integración entre el sistema de navegación inercial y el receptor GNSS y las ventajas y desventajas de cada uno. La integración se lleva a cabo en MATLAB utilizando el GPS y los datos simulados de sensores inerciales. [CATALÀ] L'objectiu de la tesi és proporcionar un marc simplificat per a la implementació bàsica de la integració del GNSS/INS utilitzant Software Defined receptor de ràdio. Aquesta tesi investiga les diferents arquitectures d'integració entre el sistema de navegació inercial i el receptor GNSS i els avantatges i desavantatges de cada un. La integració es porta a terme en MATLAB utilitzant el GPS i les dades simulades de sensors inercials.

This project studies the usefulness of GPS technology for the development of personal location applications. It is focused on the system and technical features study. On the other hand, it proposes how to improve current system applications trying to enhance its overall performance. From a technical point of view, it shows the signal features of the system, like the wave form or the modulation, together with the required system extra devices, access protocols and implementation issues. Moreover, computer simulations of representative scenarios have been carried out in order to assess the potential achievable benefits. The parts of this project are, first of all, the study of the system itself (understanding the current state of the art, all its features and protocols), the proposal of some improvements (based on the system study) and the implementation of computer simulation to validate this improvements. The final work that is shown below has such a final purpose to offer a system, that could be easily implemented, for kids location using a GPS locator and a GPRS device cell phone device. This sort of devices are currently in a good moment to be sold. This document shows the current situation of these devices and the demand and offer of these products (in Spain). It also shows the GPRS coverage map in Spain because this system tought, mainly, to be implemented in Spain. Although currently, as has been said before, these kind of devices already exist, in this document the technical specifications explained are only thought for the system explained in this document and they differ from the other specifications from the other similar products/systems. This document offers the necessary information and specifications to enable the system creation and production. Using the created program for this final work, we can obtain information about the utility that this system can offer depending on the kid ususal environment. The program, created in JAVA language and using the Netbeans platform (explained below in this document), allows to create any scenario showing the GPRS communication quality whenever the communication can be possible and this is how the program shows the utility of the system for the kid environment. Finally, in the end of this document, are shown the difficulties that have been appearing during the creation of this final work and the job done every month to create this system that allows to locate kids ans its simulation program.

Free-space optical communication systems between satellites and also between a satellite and a ground station foreseen in Europe in the mid-1990's require far-field on-ground experimentation prior to launch. To identify possible scenarios for a test site, an atmospheric near-infrared semiconductor laser link was set up between two mountain peaks 143.5 km apart located in two islands in the Canarian Archipelago. The link confirmed the excellent atmospheric conditions of this scenario (low attenuation, turbulence-induced effects below or close to saturation during nighttime) in addition to its high availability. >

For a given geometry, the coherence time of a GNSS-R waveform can be initially related to the significant wave height.However, when the coherence time is analyzed, several issues shall be considered, such as the geometry (i.e altitude, elevation angle). This work presents a review of the coherence time and its dependence on the geometry. In addition, the impact that the SWH has on both the coherence time and elevation angles is analyzed. Real data from different scenarios (spaceborne, airborne, and ground based) are used in this study.

Cat-2 Assembly, Integration and Verification (AIV) activities of the Engineering Model (EM) and the Flight Model (FM) are being carried out at present. The Attitude Determination and Control System (ADCS) and Flight Software (FSW) validation campaigns will be performed at Universitat Politècnica de Catalunya (UPC) during the incomings months. An analysis and verification of the 3Cat-2 key mission requirements has been performed. The main results are summarized in this work.

Despite their limited lifespan and reduced cost, nanosatellite missions have proved to be suitable platforms for Earth observation, scientific experiments, and technology demonstration. During the last years, the number of nanosatellite missions has noticeably increased, posing the need to improve several system characteristics to ultimately endorse the full potential of this class of spacecraft. In this context, this paper presents three design guidelines that can be applied in nanosatellite software to improve the system robustness, modularity, and autonomy. The design guidelines presented in this paper, namely, hierarchy-enabled robustness, payload-oriented modularity, and onboard planning capabilities, are complemented with a structured review of software techniques and architectural concepts that have been found in the literature. The paper justifies that these systemwide qualities are some of the most critical when designing flight software for CubeSat-like spacecraft and explores how they can improve mission performances and operability, enhance the system’s tolerance to failures, and ease the development cycles. Finally, this paper illustrates the application of the design guidelines by detailing the onboard software architecture for the Cat3-1, a CubeSat program carried out at the Nano-Satellite and Payload Laboratory of the Technical University of Catalonia—UPC BarcelonaTech.

En este trabajo se pretende realizar el diseño de un microsatélite mediante herramientas de diseño asistido por ordenador (CAD) y el posterior análisis del modelo. El objetivo principal es realizar un diseño lo más real posible que sea estructuralmente viable y capaz de soportar las condiciones a las que se ve expuesto durante el lanzamiento. Por ello se ha realizado un estudio del mercado actual, para dotar a la misión de componentes reales que cumplan los requisitos establecidos por esta y que conformaran la carga útil y los diferentes subsistemas: estructura, control de altitud, computación, potencia, control térmico y telecomunicaciones. Mediante la herramienta CAD, mencionada anteriormente, se han diseñado los componentes con sus parámetros más característicos ya sean de forma o material. Este diseño se ha acompañado de la descripción del funcionamiento de cada dispositivo además del rol que cumple en el conjunto del microsatélite. Seguidamente, una vez se ha obtenido el modelado de todos los componentes el ensamblaje definitivo del microsatélite está listo para su montaje y consecuentemente el modelo final que se debe analizar. En el análisis se intentan simular las condiciones estándar de un lanzamiento con la intención de comprobar la reacción del diseño. Los primeros cálculos realizados nos han llevado a la obtención de resultados que no eran viables, en los que la estructura cedía a los esfuerzos y resultaba dañada. En consecuencia se han tomado medidas y se ha procedido al refinamiento del modelo hasta hallar valores que sí fueran viables.

Design and implementation of the communications protocols of the 3cat-2 nanosatellite and a remotely controlled receiving ground station consisting of a VHF and S-band down-links, and a UHF up-link.

The Lower thermosphere (between 80 and 350 km) is quite badly known due to the scarcity of satellites in this region. Nevertheless, it is an important region in several respects. Firstly, because its density determines when a falling satellite will reenter the dense layers of the atmosphere, thus affecting at reentry predictions. Secondly, it is highly relevant to understand physical processes in the atmosphere, and to study the Earth-Sun relation. Miniaturization of electronic devices has been driven in recent years by consumer applications like smartphones and computers. However, these electronic devices can also be employed to design small but rather capable satellites with total masses below 100 grams, thus in the range of femtosatellites. Given the limited capabilities of femtosatellites in terms of power, computational capability, attitude determination and control, to cite just a few, it is important to identify the advantages of femtosatellites as compared with their larger relatives. As far as we can see, the main advantages are in cost (including launch cost) and on the possibility of launching swarms of dozens, hundreds or even thousands of femtosatellites. In any case, it is obvious that femtosatellites cannot (and should not) compete with larger satellites devoted to, for example, meteorology, communications or astronomy, at least in their standard ways of operation. To fix the terminology, a swarm is defined as a cluster of satellites that has no control over their relative position (thus has no formation-flight nor constellation control capabilities) and are distributed over a wide area, even surrounding the whole Earth, to accomplish some mission goals. Then, a large number of femtosatellites of spherical shape would provide an instantaneous determination of atmospheric parameters simultaneously in a large number of points. These femtosatell ites would include three micro-g accelerometers (to calculate the acceleration in the three axes), a microprocessor with low power consumption, a GPS, a flash memory, voltage regulators and a transmitter plus a primary battery (with a high energetic density) to feed all the systems. All these electronics, and the rest needed to perform the bus of the satellite, would be embedded in a sphere of aerogel to resist the aerodynamic heating, and the effects of atomic oxygen. Due to their spherical shape, the ballistic coefficient for these femtosatellites is independent of the attitude. As it is reasonable, the lower the ballistic coefficient the larger the deceleration due to drag; this makes for a better measure of the acceleration, but greatly reduces the lifetime in orbit. A compromise would be to have around 1 week of orbital lifetime, and accelerations of some micro-g's. The main objectives of this project would be: an analysis of the current knowledge about the lower thermosphere; discussing the general trends of the mission as a whole, and describing some further difficulties or problems associated with them; making a preliminary design of the femtosatellite based on commercial- off-the-shelf (COTS) technology; and describing some possible future developments.

Aquest treball presenta el procediment del disseny de la Power and Control Unit (PCU) dels Receiver Amplifier Subsystem(RAS) del satèl·lit Biomass, contenint el procés de disseny, simulacions i la posterior implementació.En la primera part del projecte es posa en context al lector i es dóna a conèixer la necessitat de la PCU en els receptors del radar del satèl·lit.La PCU que s’ha dissenyat, es compon d’un convertidor Flybackde tres sortides regulades que pot rebre telecomandes d’encesa i apagada, i que envia telemetries del corrent de primari i de tensió de la branca principal de secundari. També disposa de diferents proteccions, tant d’overvoltagecom d’undervoltagei d’overcurrent.Seguidament s’entra a la part principal del treball, on en el primer lloc hi ha una introducció als convertidors de topologia Flyback, llavors es veurà com s’ha dissenyat la PCU,i quins mètodes s’han seguit. Dintre del’apartat de disseny es pot trobar l’explicació de l’elecció del transformador principal, del MOSFET i dels díodes rectificadors,i també es trobarà el disseny tant del filtre de sortida com el d’entrada, el disseny del llaç de control i el sistema de telecomandes i telemetries.Finalment es presenten els resultats de les simulacions i les mesures fetes en la placa, conjuntament amb les conclusions.

Global Navigation Satellite Systems - Reflectometry (GNSS-R) has opened promising results for remote sensing applications. The broadcast of new signals with wider bandwidth provides an opportunity to increase the performance of GNSS reflectometry applications. The Microwave Interferometric Reflectometer (MIR) is an instrument being developed to compare different GNSS-R techniques, namely the conventional and interferometric ones, and assess the capabilities of these new signals and bands of the GPS and Galileo systems. This work describes the tests to validate the beamforming system.

The purpose of this work is to characterize the performance of different interpolation methods in order to build a global model of ionospheric free electron density, directly derived from the inversions of GNSS occultation data. Indeed, the occultation of GNSS satellites, observed from dual-frequency L-band receivers onboard Low Earth Orbiters (LEOs) is providing valuable ionospheric data since the first mission (GPS/MET) in 1995. This is an excellent scenario to derive, in a simple and precise way, the almost instantaneous distribution of ionospheric electron density in a region of few thousands of kilometers from each occultation event. This can be done, for instance, applying the Improved Abel Transform Inversion technique proposed during the last decade by the UPC authors. In such approach the horizontal gradient of the electron density is taken from the Vertical Total Electron Content gradient as proxy. This assumption increases the accuracy of the electron density retrieval, compared with the Classical Abel Transform Inversion, which assumes spherical symmetry in the occultation region. The availability of numerous occultation events (up to 2000 per day during the full availability of the FORMOSAT-3/COSMIC LEO constellation) enables the execution of studies on the feasibility of simple but accurate ways to interpolate such fields of electron density values, given by each occultation, in an overall electron density model

Treball acadèmic presentat a dues titulacions: Enginyeria Electrònica i Màster en Enginyeria Electrònica The subject of labor of this project is based in PDO systems (Pulsed Digital Oscillator) for resonant MEMS with thermoelectric actuation. As its name indicates, they are a type of digital control oscillators, using a PLD, in which the MEMS actuation signal is formed by pulses. Its main characteristic is that, externally, its operation can be controlled so that the MEMS can oscillate in one of its different points of resonance. In addition, it captures and sends the digital value of this frequency to a PC. For the development of this project, we designed a new PDO model that fits to the maximum the definitive model intended for the CubeSat. The control, in this case, is made entirely from the PC, the same that receive the value of the oscillation frequency in digital measures. The aim of this project is to design a PDO control that allows making rounds of alternated measures for each of the modes for an undetermined period of time and save them in a text file with the corresponding time value. This approach and the PDO design conditions have forced the design of an auxiliary board needed to set communication with the PC as well as to the PLD can be programmed. The second purpose of this project has been the study of the behavior of the resonant frequency for the different MEMS modes depending on the pressure and to obtain their theoretical model. The realized work was to search a theoretical mode previously designed for MEMS with similar characteristics and to check that what this model says be what we obtain in the experimental measures. We have shown that the theoretical model characterize the behavior for the first two oscillation modes correctly. The last purpose has been to check the correspondence between the modes in which this PDO oscillates for different configurations and the modes in which it would have to oscillate according to the theory. Firstly, we have shown that using the no-fractional delays theory we do not achieve this correspondence. Then, we used the fractional delays theory to show the effect of the phase shift and the losses in the oscillation and anti-oscillation zones.

L’objectiu d’aquest TFC consisteix en dissenyar el bus per un satèl•lit d’uns 30 kg per un experiment sobre l’efecte de les radiacions sobre microorganismes. En funció dels drivers imposats per l’experiment (en part encara per determinar), s’hauran d’aplicar diferents tècniques per tal d’assolir els objectius. En aquest treball es pretén realitzar el disseny basic, o disseny de fase A, d’un microsatèl•lit per a una missió en orbita al voltant de la Terra. L’objectiu d’aquesta missió es mesurar els efectes de la radiació ionitzant sobre els organismes unicel•lulars eucariotes exposats a l’espai durant temps de l’ordre d’anys. Al llarg d’aquest treball avaluem els diferents factors que afecten les primeres fases del disseny del satèl•lit, i identifiquem i descrivim els diferents subsistemes i components necessaris que fan possible el seu correcte funcionament i el de la pròpia carrega útil. En aquest sentit, el primer pas ha estat l’elecció de l’orbita, ja que, com justifiquem al llarg del text, les condicions d’aquesta afecten al disseny global del satèl•lit. Per poder realitzar la missió i que la carrega útil acompleixi els seus objectius son necessaris els següents subsistemes: estructura, control t’orbita, computació, potencia, control tèrmic i telecomunicacions. Cadascun d’aquests subsistemes realitza una tasca concreta i imprescindible en el còmput global de la missió, que es detalla al capítol corresponent del present document. El fet que el disseny de cada subsistema afecta directa o indirectament el disseny de la resta fa que el procés de definició sigui molt no lineal. Quan ho hem considerat convenient, hem inclòs en el text els raonaments que ens han dut a prendre les decisions adients.. També, es important ressaltar, que en aquest tipus de missió es essencial la robustesa del sistema ja que, com es veurà, un error pot posar en perill l’èxit de tota la missió. El sistema mes robust, es el mes senzill, i a l’hora de realitzar el disseny hem tingut present aquest concepte, ja que així hem pogut optimitzar recursos i minimitzarem riscos. Finalment, encara que el projecte proposat es de caràcter acadèmic, hem donat especial importància al fet que el disseny sigui realista en la mesura del possible, i els components que hem proposat per la construcció del satèl•lit existeixen al mercat.

This thesis work concentrates on the development of telecommand and telemetry handler software for a 2 kg Aalto-2 nanosatellite, currently scheduled for launch in October 2016. The satellite is part of the international QB50 termosphere mission and it is developed by Aalto University in Espoo, Finland. The telecommand and telemetry (TC/TM) handler, in charge of communications, is one of the most important systems of satellite software, which is executed by On Board Computer (OBC). In this thesis, the TC/TM handler subsystem is designed, giving it a special attention in maintaining simplicity and reliability. The design process is started with the derivation of requirements and constraints. The software is implemented for FreeRTOS, an open-source real-time operating system, which is selected as operation environment of the satellite OBC software. The designed software uses a Concatenative Language approach and complies with ECSS-PUS standard. It features different libraries that provide capabilities for on-board data handling needs, the most notable of which is the Dyncall library. The library provides functions of dynamic function call in C. The UHF driver handles incoming and outgoing low-level communications protocols, and the Coffee File System implements storage management. The work gives an overview of small satellite communication architectures and relevant standards and interfaces. Esta tésis se centra en el desarrollo de sistemas de telecontrol y software controlador de telemetría para el nanosatélite Aalto-2, cuyo lanzamiento está previsto para octubre de 2016. El satélite forma parte de la misión internacional QB50 termosphere y ha sido desarrollado por la Universidad de Aalto en Espoo, Finlandia. El controlador de telecomando y telemetría (TC/TM), a cargo de las comunicaciones, es uno de los sistemas más importantes del software del satélite. Este software es ejecutado por el Ordenador de abordo (OBC). El proceso de diseño se inicia con la derivación de los requisitos y limitaciones. El software está implementado para FreeRTOS, un sistema operativo en tiempo real de código abierto, que es seleccionado como entorno operativo del software del OBC. El software diseñado utiliza un enfoque de programación concatenativa y cumple con la norma de ECSS-PUS. Cuenta con diferentes librerias que proporcionan capacidades de datos de abordo necesidades de manipulación, el más notable de los cuales es la libreria Dyncall. Esta proporciona funciones de llamada dinámica en C. Los drivers de la UHF maneja los protocolos de comunicación de bajo nivel de entrada y salida, y el sistema de archivo es implementado por el Coffe File System o CFS. El trabajo ofrece una visión general de las arquitecturas de comunicaciones de nanosatélites, las normas pertinentes y las interfaces. Aquesta tési es centra en el desenvolupament de sistemes de telecontrol i programari controlador de telemetria per al nanosatèl·lit Aalto-2, el llançament del qual està previst per octubre del 2016. El satèl·lit forma part de la missió internacional QB50 termosphere i ha estat desenvolupat per la Universitat d'Aalto a Espoo, Finlàndia. El controlador de telecomandament i telemetria (TC / TM), se'n fa càrrec de les comunicacions i és un dels sistemes més importants del programari del satèl·lit. Aquest és executat per l'ordinador d'abord (OBC). El procés de disseny s'inicia amb la derivació dels requisits i limitacions. El programari està implementat per FreeRTOS, un sistema operatiu en temps real de codi obert, que és seleccionat com a entorn operatiu del OBC. El programari dissenyat utilitza un enfocament de programació concatenada i compleix amb la norma de ECSS-PUS. Compta amb diferents llibreries que proporcionen capacitats de dades d'abordo necessitats de manipulació, el més notable dels quals és la llibreria Dyncall. Aquesta proporciona funcions de crida dinàmica en C. Els drivers de la UHF controla els protocols de comunicació a baix nivell d'entrada i sortida, i el sistema d'arxiu és implementat pel Coffe File System o CFS. El treball ofereix una visió general de les arquitectures de comunicacions de nanosatèl·lits, les normes pertinents i les interfícies.

This thesis presents the preliminary design and a first approach of the performance analysis of a navigation system based on GPS and ORBCOMM constellations for cube-class nanosatellites. The aim is to work as a part of a mission design which objective is to test new technologies in space using cube-class nanosatellites. For this, Il Politecnico di Milano has a CubeSat for teaching purposes called Palamede. A CubeSat is a 10x10x10 cm cube shaped nanosatellite with a maximum weight of 1 kg. This work briefly reviews the CubeSat state of the art and concepts concerning position and orbit determination. Also, this is supported with appendices where there are the computation algorithms, tables with data, additional concepts and the Palamede overview. To begin with, the primary work to do is to find the best orbit in terms of visibility from both constellations with the initial requirements. Once the orbit is found, the second step is to determine the orbital period and identify possible repetitions of the accesses. To continue with it, the repeated access time bands are analyzed to determine which ones have time duration higher than 5 minutes (required for links). Additionally, from these time bands, is extracted from STK, in discrete time, all required data to compute the CubeSat position and analyze the quality of the position determination in terms of used GPS satellites for the computation. Finally, a pair of CubeSats that are separated 100 meters between them, flying in formation and in the same previous orbit, are analyzed with the same procedure. For this purpose, STK is used to simulate the cubesat orbits and constellations considering orbit perturbations with HPOP (High Precision Orbit Propagation). This propagator is used because the time simulation of one month and its reliability. For higher simulation time will be recommended to use LOP (Long-term Orbit Propagator) because computer performance in simulations. STK is very useful for simulation because its good-looking and friendly interface, like the 3D and 2D windows.

Key features of satellite communications such as wide-scale coverage, broadcast/multicast support and high availability, together with significant amounts of new satellite capacity coming online, anticipate new opportunities for satellite communications services as an integral part within upcoming 5G systems. To materialize these opportunities, satellite communications services have to be provisioned and operated in a more flexible, agile and cost-effective manner than done today. In this context, this paper firstly describes the architecture of a satellite ground segment system that builds on the introduction of Software Defined Networking (SDN) and Network Function Virtualization (NFV) technologies and then examines a use case for the realization of End-to-End Traffic Engineering in a combined terrestrial-satellite network used for mobile backhauling.

©2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This paper presents a statistical analysis of the crosstalk phenomenon in interferometric Global Navigation Satellite Systems Reflectometry (iGNSS-R). Crosstalk occurs when the Delay-Doppler Map (DDM) of a tracked satellite overlaps others fromundesired satellites. This study is performed for ground-based and airborne receivers and for a receiver onboard the International Space Station (ISS) such as the upcoming GNSS Reflectometry, Radio Occultation and Scatterometry onboard ISS experiment. Its impact on ocean altimetry retrievals is analyzed for different antenna arrays. Results show that for elevation angles higher than 60 degrees, crosstalk can be almost permanent from ground, up to 61% from airborne receivers at 2-km height, and up to similar to 10% at the ISS. Crosstalk can only be mitigated using highly directive antennas with narrow beamwidths. Crosstalk impact using a seven-element hexagonal array still induces large errors on ground, but reduces to centimeter level on airborne receivers, and is negligible from the ISS.

Este proyecto realiza un estudio sobre las diferentes opciones referentes a la Realidad Aumentada, como primera parte. La Realidad Aumentada es una tecnología que en los últimos años ha experimentado un gran desarrollo. La Realidad Aumentada consiste en sobreponer información virtual con la ya existente realidad física. Como segunda parte, se escoge una de estas opciones, NyARToolkit, y se explica el funcionamiento del sistema de coordenadas basado en marcadores. El sistema basado en marcadores, consiste, como se verá más adelante, en asociar información a un marcador (generalmente una hoja de papel con un dibujo negro) y mostrar esa información en cuanto el marcador es capturado por la cámara y reconocido por la aplicación de Realidad Aumentada. Todo ello superponiéndolo con el plano real de la cámara. La tercera parte consiste en conseguir una aplicación de Realidad Aumentada sin el uso de marcadores y con la posibilidad de poder añadir un modelo 3D creado por nosotros mismos. El siguiente punto, es añadir tratamiento de coordenadas GPS a toda la aplicación en función de un punto a observar y la posición GPS del usuario.