156 research outputs found

    API para procedimentos de teste em sistemas embutidos

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    The proposed case study takes a satellite control application as system under test and entails extending a simple simulator for the system component this application interacts with. Atop of these shall be developed test procedures to study whether there are practical limitations of using simple procedures to test complex interactions between the satellite control application and its simulated environment. The objective of the proposed work is to define a test frontend API that enables simple test procedures while providing all the means required to test complex machine-to-machine (M2M) interactions, having the system under test (SUT) hard real-time characteristics.O caso de estudo proposto toma uma aplicação de controlo de um satélite como um sistema a ser testado e implica a extensão de um simulador simples para o componente do sistema com o qual esta aplicação interage. Em cima destes devem ser desenvolvidos procedimentos de teste para estudar se há limitações práticas ao usar procedimentos simples para testar interações complexas entre a aplicação de controlo do satélite e o ambiente simulado. O objetivo do trabalho proposto é definir uma API de teste que possibilite procedimentos de teste simples e forneça todos os meios necessários para testar interações complexas máquina a máquina, tendo o sistema sob teste características de tempo real.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

    A comparative analysis of algorithms for satellite operations scheduling

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    Scheduling is employed in everyday life, ranging from meetings to manufacturing and operations among other activities. One instance of scheduling in a complex real-life setting is space mission operations scheduling, i.e. instructing a satellite to perform fitting tasks during predefined time periods with a varied frequency to achieve its mission goals. Mission operations scheduling is pivotal to the success of any space mission, choreographing every task carefully, accounting for technological and environmental limitations and constraints along with mission goals.;It remains standard practice to this day, to generate operations schedules manually ,i.e. to collect requirements from individual stakeholders, collate them into a timeline, compare against feasibility and available satellite resources, and find potential conflicts. Conflict resolution is done by hand, checked by a simulator and uplinked to the satellite weekly. This process is time consuming, bears risks and can be considered sub-optimal.;A pertinent question arises: can we automate the process of satellite mission operations scheduling? And if we can, what method should be used to generate the schedules? In an attempt to address this question, a comparison of algorithms was deemed suitable in order to explore their suitability for this particular application.;The problem of mission operations scheduling was initially studied through literature and numerous interviews with experts. A framework was developed to approximate a generic Low Earth Orbit satellite, its environment and its mission requirements. Optimisation algorithms were chosen from different categories such as single-point stochastic without memory (Simulated Annealing, Random Search), multi-point stochastic with memory (Genetic Algorithm, Ant Colony System, Differential Evolution) and were run both with and without Local Search.;The aforementioned algorithmic set was initially tuned using a single 89-minute Low Earth Orbit of a scientific mission to Mars. It was then applied to scheduling operations during one high altitude Low Earth Orbit (2.4hrs) of an experimental mission.;It was then applied to a realistic test-case inspired by the European Space Agency PROBA-2 mission, comprising a 1 day schedule and subsequently a 7 day schedule - equal to a Short Term Plan as defined by the European Space Agency.;The schedule fitness - corresponding to the Hamming distance between mission requirements and generated schedule - are presented along with the execution time of each run. Algorithmic performance is discussed and put at the disposal of mission operations experts for consideration.Scheduling is employed in everyday life, ranging from meetings to manufacturing and operations among other activities. One instance of scheduling in a complex real-life setting is space mission operations scheduling, i.e. instructing a satellite to perform fitting tasks during predefined time periods with a varied frequency to achieve its mission goals. Mission operations scheduling is pivotal to the success of any space mission, choreographing every task carefully, accounting for technological and environmental limitations and constraints along with mission goals.;It remains standard practice to this day, to generate operations schedules manually ,i.e. to collect requirements from individual stakeholders, collate them into a timeline, compare against feasibility and available satellite resources, and find potential conflicts. Conflict resolution is done by hand, checked by a simulator and uplinked to the satellite weekly. This process is time consuming, bears risks and can be considered sub-optimal.;A pertinent question arises: can we automate the process of satellite mission operations scheduling? And if we can, what method should be used to generate the schedules? In an attempt to address this question, a comparison of algorithms was deemed suitable in order to explore their suitability for this particular application.;The problem of mission operations scheduling was initially studied through literature and numerous interviews with experts. A framework was developed to approximate a generic Low Earth Orbit satellite, its environment and its mission requirements. Optimisation algorithms were chosen from different categories such as single-point stochastic without memory (Simulated Annealing, Random Search), multi-point stochastic with memory (Genetic Algorithm, Ant Colony System, Differential Evolution) and were run both with and without Local Search.;The aforementioned algorithmic set was initially tuned using a single 89-minute Low Earth Orbit of a scientific mission to Mars. It was then applied to scheduling operations during one high altitude Low Earth Orbit (2.4hrs) of an experimental mission.;It was then applied to a realistic test-case inspired by the European Space Agency PROBA-2 mission, comprising a 1 day schedule and subsequently a 7 day schedule - equal to a Short Term Plan as defined by the European Space Agency.;The schedule fitness - corresponding to the Hamming distance between mission requirements and generated schedule - are presented along with the execution time of each run. Algorithmic performance is discussed and put at the disposal of mission operations experts for consideration

    Analyse und Erweiterung eines fehler-toleranten NoC für SRAM-basierte FPGAs in Weltraumapplikationen

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    Data Processing Units for scientific space mission need to process ever higher volumes of data and perform ever complex calculations. But the performance of available space-qualified general purpose processors is just in the lower three digit megahertz range, which is already insufficient for some applications. As an alternative, suitable processing steps can be implemented in hardware on a space-qualified SRAM-based FPGA. However, suitable devices are susceptible against space radiation. At the Institute for Communication and Network Engineering a fault-tolerant, network-based communication architecture was developed, which enables the construction of processing chains on the basis of different processing modules within suitable SRAM-based FPGAs and allows the exchange of single processing modules during runtime, too. The communication architecture and its protocol shall isolate non SEU mitigated or just partial SEU mitigated modules affected by radiation-induced faults to prohibit the propagation of errors within the remaining System-on-Chip. In the context of an ESA study, this communication architecture was extended with further components and implemented in a representative hardware platform. Based on the acquired experiences during the study, this work analyses the actual fault-tolerance characteristics as well as weak points of this initial implementation. At appropriate locations, the communication architecture was extended with mechanisms for fault-detection and fault-differentiation as well as with a hardware-based monitoring solution. Both, the former measures and the extension of the employed hardware-platform with selective fault-injection capabilities for the emulation of radiation-induced faults within critical areas of a non SEU mitigated processing module, are used to evaluate the effects of radiation-induced faults within the communication architecture. By means of the gathered results, further measures to increase fast detection and isolation of faulty nodes are developed, selectively implemented and verified. In particular, the ability of the communication architecture to isolate network nodes without SEU mitigation could be significantly improved.Instrumentenrechner für wissenschaftliche Weltraummissionen müssen ein immer höheres Datenvolumen verarbeiten und immer komplexere Berechnungen ausführen. Die Performanz von verfügbaren qualifizierten Universalprozessoren liegt aber lediglich im unteren dreistelligen Megahertz-Bereich, was für einige Anwendungen bereits nicht mehr ausreicht. Als Alternative bietet sich die Implementierung von entsprechend geeigneten Datenverarbeitungsschritten in Hardware auf einem qualifizierten SRAM-basierten FPGA an. Geeignete Bausteine sind jedoch empfindlich gegenüber der Strahlungsumgebung im Weltraum. Am Institut für Datentechnik und Kommunikationsnetze wurde eine fehlertolerante netzwerk-basierte Kommunikationsarchitektur entwickelt, die innerhalb eines geeigneten SRAM-basierten FPGAs Datenverarbeitungsmodule miteinander nach Bedarf zu Verarbeitungsketten verbindet, sowie den Austausch von einzelnen Modulen im Betrieb ermöglicht. Nicht oder nur partiell SEU mitigierte Module sollen bei strahlungsbedingten Fehlern im Modul durch das Protokoll und die Fehlererkennungsmechanismen der Kommunikationsarchitektur isoliert werden, um ein Ausbreiten des Fehlers im restlichen System-on-Chip zu verhindern. Im Kontext einer ESA Studie wurde diese Kommunikationsarchitektur um Komponenten erweitert und auf einer repräsentativen Hardwareplattform umgesetzt. Basierend auf den gesammelten Erfahrungen aus der Studie, wird in dieser Arbeit eine Analyse der tatsächlichen Fehlertoleranz-Eigenschaften sowie der Schwachstellen dieser ursprünglichen Implementierung durchgeführt. Die Kommunikationsarchitektur wurde an geeigneten Stellen um Fehlerdetektierungs- und Fehlerunterscheidungsmöglichkeiten erweitert, sowie um eine hardwarebasierte Überwachung ergänzt. Sowohl diese Maßnahmen, als auch die Erweiterung der Hardwareplattform um gezielte Fehlerinjektions-Möglichkeiten zum Emulieren von strahlungsinduzierten Fehlern in kritischen Komponenten eines nicht SEU mitigierten Prozessierungsmoduls werden genutzt, um die tatsächlichen auftretenden Effekte in der Kommunikationsarchitektur zu evaluieren. Anhand der Ergebnisse werden weitere Verbesserungsmaßnahmen speziell zur schnellen Detektierung und Isolation von fehlerhaften Knoten erarbeitet, selektiv implementiert und verifiziert. Insbesondere die Fähigkeit, fehlerhafte, nicht SEU mitigierte Netzwerkknoten innerhalb der Kommunikationsarchitektur zu isolieren, konnte dabei deutlich verbessert werden

    Verification and integration of the management and control software for the Near Infrared Spectrometer Photometer of the Euclid space mission

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    The thesis comprises five chapters covering different items and phases of the work accomplished during my Ph.D program. Such work is part of the Euclid Project, a very high-profile space-based scientific mission designed to accurately measure the expansion history of the universe and the growth of cosmic structures. The first chapter is an introduction to the Euclid space mission and a description of Euclid’s scientific goals and instrumentation. The payload is a telescope that hosts two instruments capable of taking images at different wavelengths. In particular, the chapter provides a detailed description of the Near Infrared Spectrometer Photometer (NISP). The second chapter presents a detailed description of the NISP Warm Electronics (WE) with particular emphasis on the Data Processing Unit (DPU), the Instrument Control Unit (ICU), their application software (ASW), and the communication among them. The Assembly, Integration, Validation, and Testing (AIV/AIT) of such boards and the corresponding software are the main subjects of my Ph.D. study. Chapters 3, 4, and 5 which take into consideration the AIV activities and the specifically designed software tools, detail my contribution to the NISP WE AIV. The AIV of the NISP on-board software required a careful design and the development of software tools to verify functionality and performances. Great care was taken in the development of the software of the DPU test equipment controlling the interface with the DPU. I developed it in close cooperation with the NISP AIV/AIT team, the NISP-Electrical Ground Support Equipment (EGSE) team, and two industries (OHB Italia for the DPU hardware design and construction and Temis for the procurement of the DPU TE). The developed software was delivered to the industries and is now used for the validation of the DPU Electro Qualified Model (EQM) and the Flight Model (FM). Chapter 4 describes the DPU test campaign. I took part in the integration of the Application Software in the DPU board at OHB Italy and at INAF Padua. Chapter 5 illustrates the AIV/AIT activity for the validation of the NISP Avionic Model (AVM) before delivery to Thales Alenia Space Italia (TAS-I)

    Software Development and Detector Characterization of the EUCLID Near-Infrared Spectro-Photometer

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    The Euclid space mission, approved by the European Space Agency, is planned to perform an extensive survey over a 6 years period, beginning end of 2020. The satellite will be equipped with two instruments, a visible imager and a near-infrared spectro-photometer (NISP). These instruments will allow to measure the shape and redshift of galaxies over a large fraction of the extragalactic sky in order to study the evolution of cosmic structures, the accelerated expansion of the Universe and the nature of dark matter. This thesis has been carried out in the context of the INFN team participating in Euclid. I have contributed to the development of a software simulating the Euclid Spacecraft commanding and responding towards the NISP Instrument Control Unit. By this simulator the testing and validation of the functionalities of the Control Unit Application Software are made possible. My PhD activity abroad (6 months) was done at the CPPM Lab in Marseille collaborating with the local group in charge of the characterization of NISP infrared detectors. I took part in data acquisition shifts during calibration campaigns and I carried out an analysis on infrared detector dark current's dependence on temperature. By this analysis it was proved that the dark current of infrared detectors is compliant with Euclid requirements and that its behaviour in the range of Euclid operation temperatures is well understood

    The control unit of the near infrared spectrograph of the Euclid space mission: detailed design

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    The Near Infrared Spectrograph and Photometer (NISP) is one of the instruments on board the ESA EUCLID mission. The Universidad Polit´ecnica de Cartagena and Instituto de Astrof´ısica de Canarias are responsible of the Instrument Control Unit of the NISP (NI-ICU) in the Euclid Consortium. The NI-ICU hardware is developed by CRISA (Airbus Defence and Space), and its main functions are: communication with the S/C and the Data Processing Unit, control of the Filter and Grism Wheels, control of the Calibration Unit and thermal control of the instrument. This paper presents the NI-ICU status of definition and design at the end of the detailed design phase. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.The authors want to acknowledge the contributions provided by the NISP system team of the Euclid Consortium to this work. This work has been supported by the Spanish Ministry of Economy under the projects ESP2013-48362-C2-2-P, ESP2014-56869-C2-2-P and ESP2015-69020-C2-2-R, as well as by ERDF funds from the European Commission

    A Symbiotic Approach to Designing Cross-Layer QoS in Embedded Real-Time Systems

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    International audienceNowadays there is an increasing need for embedded systems to support intensive computing while maintaining traditional hard real-time and fault-tolerant properties. Extending the principle of multi-core systems, we are exploring the use of distributed processing units interconnected via a high performance mesh network as a way of supporting distributed real-time applications. Fault-tolerance can then be ensured through dynamic allocation of both computing and communication resources. We postulate that enhancing QoS (Quality of Service) for real-time applications entails the development of a cross-layer support of high-level requirements, thus requiring a deep knowledge of the underlying networks. In this paper, we propose a new simulation/emulation/experimentation framework, ERICA, for designing such a feature. ERICA integrates both a network simulator and an actual hardware network to allow implementation and evaluation of different QoS-guaranteeing mechanisms. It also supports real-software-in-the-loop, i.e. running of real applications and middleware over these networks. Each component can evolve separately or together in a symbiotic manner, also making teamwork more flexible. We present in more detail our discrete-event simulation approach and the in-silicon implementation with which we cross-check our solutions in order to bring real performance aspects to our work. We also discuss the challenges of running real-software-in-the-loop in a real-time context, i.e. how to bridge it with a network simulator, and how to deal with time consistency

    Simulation of IRNSS Navigation Payload Operations for End to End Payload Testing

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    Fault free operations of space vehicles have always been a challenging task. Every space mission requires stringent qualification process on ground for qualification of the space vehicle for mission operations. This paper deals with the simulation of IRNSS navigation payload operations on ground for end to end payload testing and qualification of the payload for broadcast of IRNSS navigation parameters. IRNSS is an emerging Indian regional navigation satellite system for providing the satellite based navigation service over India and neighboring region. The system is optimally designed for its space and ground segment to provide the best in class navigation service. The space segment comprises of 7 satellites with 4 satellites in geo-synchronous orbit and 3 in geo-stationary orbit. The navigation payload on-board every IRNSS spacecraft comprises of navigation signal generation unit, atomic clocks and ranging subsystems. For every IRNSS spacecraft, a series of tests are carried out during different phases of spacecraft integration and testing. The core elements of IRNSS navigation operations such as IRNSS navigation software, payload test receiver, atomic clocks and telecommand and telemetry subsystem all participate in simulation and end to end testing of navigation payload. This paper describes in detail the simulation of various mission scenarios with respect to navigation payload operations considering different phases of satellite operations, subsystems involved and environment. The simulation has been key to successful operations of IRNSS 1A and IRNSS 1B which are operational in IRNSS space segment. Keywords: IRNSS, Navigation, payload, simulatio

    Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report

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    This report describes the 2014 study by the Science Definition Team (SDT) of the Wide-Field Infrared Survey Telescope (WFIRST) mission. It is a space observatory that will address the most compelling scientific problems in dark energy, exoplanets and general astrophysics using a 2.4-m telescope with a wide-field infrared instrument and an optical coronagraph. The Astro2010 Decadal Survey recommended a Wide Field Infrared Survey Telescope as its top priority for a new large space mission. As conceived by the decadal survey, WFIRST would carry out a dark energy science program, a microlensing program to determine the demographics of exoplanets, and a general observing program utilizing its ultra wide field. In October 2012, NASA chartered a Science Definition Team (SDT) to produce, in collaboration with the WFIRST Study Office at GSFC and the Program Office at JPL, a Design Reference Mission (DRM) for an implementation of WFIRST using one of the 2.4-m, Hubble-quality telescope assemblies recently made available to NASA. This DRM builds on the work of the earlier WFIRST SDT, reported by Green et al. (2012) and the previous WFIRST-2.4 DRM, reported by Spergel et. (2013). The 2.4-m primary mirror enables a mission with greater sensitivity and higher angular resolution than the 1.3-m and 1.1-m designs considered previously, increasing both the science return of the primary surveys and the capabilities of WFIRST as a Guest Observer facility. The addition of an on-axis coronagraphic instrument to the baseline design enables imaging and spectroscopic studies of planets around nearby stars.Comment: This report describes the 2014 study by the Science Definition Team of the Wide-Field Infrared Survey Telescope mission. 319 pages; corrected a misspelled name in the authors list and a typo in the abstrac
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