14 research outputs found

    Network Topology Transformation for Fault Tolerance in SpaceWire Onboard Networks

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    The paper presents a network transformation algorithm for fault tolerance in SpaceWire onboard networks which is implemented in SANDS computer-aided design system. We give general notions on fault tolerance for onboard networks, introduce our algorithm for network transformation and give several examples of running the algorithm on different topologies

    Design and Simulation of Onboard SpaceWire Networks

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    The paper describes SpaceWire Automated Network Design and Simulation (SANDS) - the new CAD system for SpaceWire networks. SANDS system supports the full on-board network design and simulation flow, which begins from the network topology automated generation and finishes with getting the network structure, configuration and parameters setting, simulation results and statistics. The paper also provides use cases for SANDS application

    Communication platform for inter-satellite links in distributed satellite systems

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    EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    NASA Tech Briefs, April 2011

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    Topics covered include: Amperometric Solid Electrolyte Oxygen Microsensors with Easy Batch Fabrication; Two-Axis Direct Fluid Shear Stress Sensor for Aerodynamic Applications; Target Assembly to Check Boresight Alignment of Active Sensors; Virtual Sensor Test Instrumentation; Evaluation of the Reflection Coefficient of Microstrip Elements for Reflectarray Antennas; Miniaturized Ka-Band Dual-Channel Radar; Continuous-Integration Laser Energy Lidar Monitor; Miniaturized Airborne Imaging Central Server System; Radiation-Tolerant, SpaceWire-Compatible Switching Fabric; Small Microprocessor for ASIC or FPGA Implementation; Source-Coupled, N-Channel, JFET-Based Digital Logic Gate Structure Using Resistive Level Shifters; High-Voltage-Input Level Translator Using Standard CMOS; Monitoring Digital Closed-Loop Feedback Systems; MASCOT - MATLAB Stability and Control Toolbox; MIRO Continuum Calibration for Asteroid Mode; GOATS Image Projection Component; Coded Modulation in C and MATLAB; Low-Dead-Volume Inlet for Vacuum Chamber; Thermal Control Method for High-Current Wire Bundles by Injecting a Thermally Conductive Filler; Method for Selective Cleaning of Mold Release from Composite Honeycomb Surfaces; Infrared-Bolometer Arrays with Reflective Backshorts; Commercialization of LARC (trade mark) -SI Polyimide Technology; Novel Low-Density Ablators Containing Hyperbranched Poly(azomethine)s; Carbon Nanotubes on Titanium Substrates for Stray Light Suppression; Monolithic, High-Speed Fiber-Optic Switching Array for Lidar; Grid-Tied Photovoltaic Power System; Spectroelectrochemical Instrument Measures TOC; A Miniaturized Video System for Monitoring Drosophila Behavior; Hydrofocusing Bioreactor Produces Anti-Cancer Alkaloids; Creep Measurement Video Extensometer; Radius of Curvature Measurement of Large Optics Using Interferometry and Laser Tracker n-B-pi-p Superlattice Infrared Detector; Safe Onboard Guidance and Control Under Probabilistic Uncertainty; General Tool for Evaluating High-Contrast Coronagraphic Telescope Performance Error Budgets; Hidden Statistics of Schroedinger Equation; Optimal Padding for the Two-Dimensional Fast Fourier Transform; Spatial Query for Planetary Data; Higher Order Mode Coupling in Feed Waveguide of a Planar Slot Array Antenna; Evolutionary Computational Methods for Identifying Emergent Behavior in Autonomous Systems; Sampling Theorem in Terms of the Bandwidth and Sampling Interval; Meteoroid/Orbital Debris Shield Engineering Development Practice and Procedure; Self-Balancing, Optical-Center-Pivot, Fast-Steering Mirror; Wireless Orbiter Hang-Angle Inclinometer System; and Internal Electrostatic Discharge Monitor - IESDM

    Run-time reconfigurable, fault-tolerant FPGA systems for space applications

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    Cozzi D. Run-time reconfigurable, fault-tolerant FPGA systems for space applications. Bielefeld: Universität Bielefeld; 2016.The aim of this thesis is to investigate the use of Dynamic Partial Reconfiguration (DPR) on Commercial Off-the-Shelf (COTS) FPGAs in space applications. Reconfigurable systems gained interest in a wide range of application fields, including aerospace, where electronic devices are exposed to a harsh working environment. COTS SRAM-based FPGA devices represent an interesting hardware platform for this kind of systems since they combine low cost with the possibility to utilize state-of-the-art processing power as well as the flexibility of reconfigurable hardware. FPGA architectures have high computational power and thanks to their ability to be reconfigured at run-time, they became interesting candidates for payload processing in space applications. The presented Dynamic Reconfigurable Processing Module (DRPM) has been developed to investigate the use of the DPR approach for satellite payload processing. This scalable platform combines dynamically reconfigurable FPGAs with the required avionic interfaces (e.g., SpaceWire, MIL-STD-1553B, and SpaceFibre). In particular, a novel communication interface has been developed, the Heterogeneous Multi Processor Communication Interface (HMPCI), which allows inter-process communication with small latency and low memory footprint. Current synthesis tools do not support fully the DPR capabilities of FPGAs. Therefore, this thesis introduces INDRA 2.0: an INtegrated Design flow for Reconfigurable Architectures. The key part of INDRA 2.0 is DHHarMa: a Design flow for Homogeneous Hard Macros, which generates homogeneous hard macros for Xilinx FPGAs starting from a high-level description (e.g., VHDL). In particular, the homogeneous DHHarMa router is explained in detail, providing novel terminologies and algorithms, which have enabled the generation of homogeneous routed designs. Results have been shown that Design flow for Homogeneous Hard Macros (DHHarMa) can route homogeneously a communication infrastructure utilizing just between 1% and 31% more resources than the Xilinx router, which cannot provide a homogeneous solution. Furthermore, the permanent faults that can occur on FPGAs have been investigated. This thesis presents OLT(RE)2: an on-line on-demand approach to testing permanent faults induced by radiation in reconfigurable systems used in space missions. The proposed approach relies on a test circuit and custom placer and router. OLT(RE)2 exploits DPR to place the test circuits at run-time. Its goal is to test unprogrammed areas of the FPGA before using them. Experimental results of OLT(RE)2 have shown that is possible to generate, place, and route the test circuits needed to detect on average more than 99 % of the physical wires and on average about 97 % of the programmable interconnection points of a large arbitrary region of the FPGA in a reasonable time. Moreover, the test can be run on the target device without interfering the functional behavior of the system

    Economically sustainable public security and emergency network exploiting a broadband communications satellite

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    The research contributes to work in Rapid Deployment of a National Public Security and Emergency Communications Network using Communication Satellite Broadband. Although studies in Public Security Communication networks have examined the use of communications satellite as an integral part of the Communication Infrastructure, there has not been an in-depth design analysis of an optimized regional broadband-based communication satellite in relation to the envisaged service coverage area, with little or no terrestrial last-mile telecommunications infrastructure for delivery of satellite solutions, applications and services. As such, the research provides a case study of a Nigerian Public Safety Security Communications Pilot project deployed in regions of the African continent with inadequate terrestrial last mile infrastructure and thus requiring a robust regional Communications Satellite complemented with variants of terrestrial wireless technologies to bridge the digital hiatus as a short and medium term measure apart from other strategic needs. The research not only addresses the pivotal role of a secured integrated communications Public safety network for security agencies and emergency service organizations with its potential to foster efficient information symmetry amongst their operations including during emergency and crisis management in a timely manner but demonstrates a working model of how analogue spectrum meant for Push-to-Talk (PTT) services can be re-farmed and digitalized as a “dedicated” broadband-based public communications system. The network’s sustainability can be secured by using excess capacity for the strategic commercial telecommunication needs of the state and its citizens. Utilization of scarce spectrum has been deployed for Nigeria’s Cashless policy pilot project for financial and digital inclusion. This effectively drives the universal access goals, without exclusivity, in a continent, which still remains the least wired in the world

    Fault-tolerance analysis algorithm for SpaceWire onboard networks

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    The paper presents algorithms for fault tolerance evaluation which will be applied in a new computer-aided design system for SpaceWire onboard networks. We give general notions on fault tolerance for onboard networks, and introduce our algorithm for evaluation of fault tolerance in SpaceWire networks. Finally we address our future work direction on network topology transformation for fault tolerance

    Fault-tolerant satellite computing with modern semiconductors

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    Miniaturized satellites enable a variety space missions which were in the past infeasible, impractical or uneconomical with traditionally-designed heavier spacecraft. Especially CubeSats can be launched and manufactured rapidly at low cost from commercial components, even in academic environments. However, due to their low reliability and brief lifetime, they are usually not considered suitable for life- and safety-critical services, complex multi-phased solar-system-exploration missions, and missions with a longer duration. Commercial electronics are key to satellite miniaturization, but also responsible for their low reliability: Until 2019, there existed no reliable or fault-tolerant computer architectures suitable for very small satellites. To overcome this deficit, a novel on-board-computer architecture is described in this thesis.Robustness is assured without resorting to radiation hardening, but through software measures implemented within a robust-by-design multiprocessor-system-on-chip. This fault-tolerant architecture is component-wise simple and can dynamically adapt to changing performance requirements throughout a mission. It can support graceful aging by exploiting FPGA-reconfiguration and mixed-criticality.  Experimentally, we achieve 1.94W power consumption at 300Mhz with a Xilinx Kintex Ultrascale+ proof-of-concept, which is well within the powerbudget range of current 2U CubeSats. To our knowledge, this is the first COTS-based, reproducible on-board-computer architecture that can offer strong fault coverage even for small CubeSats.European Space AgencyComputer Systems, Imagery and Medi

    Journal of Telecommunications and Information Technology, 2007, nr 1

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    Adaptation of the IEEE 802.11 protocol for inter-satellite links in LEO satellite networks

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    Knowledge of the coefficient of thermal expansion (CTE) of a ceramic material is important in many application areas. Whilst the CTE can be measured, it would be useful to be able to predict the expansion behaviour of multiphase materials.. There are several models for the CTE, however, most require a knowledge of the elastic properties of the constituent phases and do not take account ofthe microstructural features of the material. If the CTE could be predicted on the basis of microstructural information, this would then lead to the ability to engineer the microstructure of multiphase ceramic materials to produce acceptable thermal expansion behaviour. To investigate this possibility, magnesia-magnesium aluminate sp~el (MMAS) composites, consisting of a magnesia matrix and magnesium aluminate s~ne'l (MAS) particles, were studied. Having determined a procedure to produce MAS fr alumina and magnesia, via solid state sintering, magnesia-rich compositions wit ~ various magnesia contents were prepared to make the MMAS composites. Further, the l\.1MAS composites prepared from different powders (i.e. from an alumina-magnesia mixture ahd from a magnesia-spinel powder) were compared. Com starch was added into the powder mixtures before sintering to make porous microstructures. Microstructural development and thermal expansion behaviour ofthe MMAS composites were investigated. Microstructures of the MAS and the MMAS composites as well as their porous bodies were quaritified from backscattered electron micrographs in terms of the connectivity of solids i.e. solid contiguity by means of linear intercept counting. Solid contiguity decreased with increasing pore content and varied with pore size, pore shape and pore distribution whereas the phase contiguity depended strongly on the chemical composition and was less influenced by porosity. ' The thermal expansion behaviour of the MAS and the MMAS composites between 100 and 1000 °C was determined experimentally. Variation in the CTE ofthe MAS relates to the degree of spinel formation while the thermal expansion of the MMAS composites depends strongly on phase content. However, the MMAS composites with similar phase compositions but made from different manufacturing processes showed differences in microstructural features and thermal expansion behaviour. Predictions of the CTE values for composites based on a simple rule-of-mixtures (ROM) using volume fraction were compared with the measured data. A conventional ROM accurately predicted the effective CTE of a range of dense alumina-silicon carbide particulate composites but was not very accurate for porous multiphase structures. It provided an upper bound prediction as all experimental values were lower. Hence, the conventional ROM was modified to take account of quantitative microstructural parameters obtained from solid contiguity. The modified ROM predicted lower values and gave a good agreement with the experimental data. Thus, it has been shown that quantitative microstructural information can be used to predict the CTE of multiphase ceramic materials with complex microstructures.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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