Design Solutions For Modular Satellite Architectures

The cost-effective access to space envisaged by ESA would open a wide range of new opportunities and markets, but is still many years ahead. There is still a lack of devices, circuits, systems which make possible to develop satellites, ground stations and related services at costs compatible with the budget of academic institutions and small and medium enterprises (SMEs). As soon as the development time and cost of small satellites will fall below a certain threshold (e.g. 100,000 to 500,000 €), appropriate business models will likely develop to ensure a cost-effective and pervasive access to space, and related infrastructures and services. These considerations spurred the activity described in this paper, which is aimed at: - proving the feasibility of low-cost satellites using COTS (Commercial Off The Shelf) devices. This is a new trend in the space industry, which is not yet fully exploited due to the belief that COTS devices are not reliable enough for this kind of applications; - developing a flight model of a flexible and reliable nano-satellite with less than 25,000€; - training students in the field of avionics space systems: the design here described is developed by a team including undergraduate students working towards their graduation work. The educational aspects include the development of specific new university courses; - developing expertise in the field of low-cost avionic systems, both internally (university staff) and externally (graduated students will bring their expertise in their future work activity); - gather and cluster expertise and resources available inside the university around a common high-tech project; - creating a working group composed of both University and SMEs devoted to the application of commercially available technology to space environment. The first step in this direction was the development of a small low cost nano-satellite, started in the year 2004: the name of this project was PiCPoT (Piccolo Cubo del Politecnico di Torino, Small Cube of Politecnico di Torino). The project was carried out by some departments of the Politecnico, in particular Electronics and Aerospace. The main goal of the project was to evaluate the feasibility of using COTS components in a space project in order to greatly reduce costs; the design exploited internal subsystems modularity to allow reuse and further cost reduction for future missions. Starting from the PiCPoT experience, in 2006 we began a new project called ARaMiS (Speretta et al., 2007) which is the Italian acronym for Modular Architecture for Satellites. This work describes how the architecture of the ARaMiS satellite has been obtained from the lesson learned from our former experience. Moreover we describe satellite operations, giving some details of the major subsystems. This work is composed of two parts. The first one describes the design methodology, solutions and techniques that we used to develop the PiCPoT satellite; it gives an overview of its operations, with some details of the major subsystems. Details on the specifications can also be found in (Del Corso et al., 2007; Passerone et al, 2008). The second part, indeed exploits the experience achieved during the PiCPoT development and describes a proposal for a low-cost modular architecture for satellite

EuFRATE: European FPGA Radiation-hardened Architecture for Telecommunications

The EuFRATE project aims to research, develop and test radiation-hardening methods for telecommunication payloads deployed for Geostationary-Earth Orbit (GEO) using Commercial-Off-The-Shelf Field Programmable Gate Arrays (FPGAs). This project is conducted by Argotec Group (Italy) with the collaboration of two partners: Politecnico di Torino (Italy) and Technische Universit¨at Dresden (Germany). The idea of the project focuses on high-performance telecommunication algorithms and the design and implementation strategies for connecting an FPGA device into a robust and efficient cluster of multi-FPGA systems. The radiation-hardening techniques currently under development are addressing both device and cluster levels, with redundant datapaths on multiple devices, comparing the results and isolating fatal errors. This paper introduces the current state of the project’s hardware design description, the composition of the FPGA cluster node, the proposed cluster topology, and the radiation hardening techniques. Intermediate stage experimental results of the FPGA communication layer performance and fault detection techniques are presented. Finally, a wide summary of the project’s impact on the scientific community is provided

Autonomous fault emulation: a new FPGA-based acceleration system for hardness evaluation

The appearance of nanometer technologies has produced a significant increase of integrated circuit sensitivity to radiation, making the occurrence of soft errors much more frequent, not only in applications working in harsh environments, like aerospace circuits, but also for applications working at the earth surface. Therefore, hardened circuits are currently demanded in many applications where fault tolerance was not a concern in the very near past. To this purpose, efficient hardness evaluation solutions are required to deal with the increasing size and complexity of modern VLSI circuits. In this paper, a very fast and cost effective solution for SEU sensitivity evaluation is presented. The proposed approach uses FPGA emulation in an autonomous manner to fully exploit the FPGA emulation speed. Three different techniques to implement it are proposed and analyzed. Experimental results show that the proposed Autonomous Emulation approach can reach execution rates higher than one million faults per second, providing a performance improvement of two orders of magnitude with respect to previous approaches. These rates give way to consider very large fault injection campaigns that were not possible in the past.This work was supported by the Directorate of Research of Madrid Community Government, Spain (Code 07/0052/2003 2) and by the European Commission and Spanish Government under MEDEA+ Project (PARACHUTE-2A701) and PROFIT Project (CIRCE-FIT-330100-2005-60)

Radiation-induced Effects on DMA Data Transfer in Reconfigurable Devices

As the adoption of SRAM-based FPGAs and Reconfigurable SoCs for High-Performance Computing increased in the last years, the use of Direct Memory Access for data transfer becomes a key feature of many reconfigurable applications even in the space industry. For such kinds of applications, radiation-induced effects are a serious issue that mines the correctness and success of mission-critical tasks. In this paper, we evaluate the effects of proton-induced errors on a DMA-based application implemented on a Xilinx Zynq-7020 FPGA in order to quantify the robustness of this module in a typical hardware-accelerated configuration. The obtained results confirm the high criticality of the DMA module on programmable logic. Moreover, the Multiple Bits Upsets effect has been evaluated. The most recurring patterns have been reported in order to provide further tools to better characterize the behavior of these systems under future fault injection campaigns, as demonstrated in the experimental results

Can we verify and intrinsically validate risk assessment results? What progress is being made to increase QRA trustworthiness?

PresentationThe purpose of a risk assessment is to make a decision whether the risk of a given situation is acceptable, and, if not, how we can reduce it to a tolerable level. For many cases, this can be done in a semi-quantitative fashion. For more complex or problematic cases a quantitative approach is required. Anybody who has been involved in such a study is aware of the difficulties and pitfalls. Despite proven software many choices of parameters must be made and many uncertainties remain. The thoroughness of the study can make quite a difference in the result. Independently, analysts can arrive at results that differ orders of magnitude, especially if uncertainties are not included. Because for important decisions on capital projects there are always proponents and opponents, there is often a tense situation in which conflict is looming. The paper will first briefly review a standard procedure introduced for safety cases on products that must provide more or less a guarantee that the risk of use is below a certain value. Next will be the various approaches how to deal with uncertainties in a quantitative risk assessment and the follow-on decision process. Over the last few years several new developments have been made to achieve, to a certain extent, a hold on so-called deep uncertainty. Expert elicitation and its limitations is another aspect. The paper will be concluded with some practical recommendations

Fault tolerance in WBAN applications

One of the most promising applications of IoT is Wireless Body Area Net-works (WBANs) in medical applications. They allow physiological signals monitoring of patients without the presence of nearby medical personnel. Furthermore, WBANs enable feedback action to be taken either periodically or event-based following the Networked Control Systems (NCSs) techniques. This thesis first presents the architecture of a fault tolerant WBAN. Sensors data are sent over two redundant paths to be processed, analyzed and monitored. The two main communication protocols utilized in this system are Low power Wi-Fi (IEEE 802.11n) and Long Term Evolution (LTE). Riverbed Modeler is used to study the system’s behavior. Simulation results are collected with 95% confidence analysis on 33 runs on different initial seeds. It is proven that the system is fully operational. It is then shown that the system can withstand interference and system’s performance is quantified. Results indicate that the system succeeds in meeting all required control criteria in the presence of two different interference models. The second contribution of this thesis is the design of an FPGA-based smart band for health monitoring applications in WBANs. This FPGA-based smart band has a softcore processor and its allocated SRAM block as well as auxiliary modules. A novel scheme for full initial configuration and Dynamic Partial Reconfiguration through the WLAN network is integrated into this design. Fault tolerance techniques are used to mitigate transient faults such as Single Event Upsets (SEUs) and Multiple Event Upsets (MEUs). The system is studied in a normal environment as well as in a harsh environment. System availability is then obtained using Markov Models and a case study is presented

V2X communications performance analysis using open-source simulators

Uno de los aspectos claves de la comunicación entre Vehículos hacia Todo (V2X) es el concepto de la conciencia cooperativa, donde el intercambio periódico del estado de las informaciones permite a los vehículos ser conscientes de su entorno aumentando así la seguridad y la eficacia del tráfico. Este proyecto consta de dos objetivos, el primero ha sido implementar y diseñar una interfaz para comunicar el Objective Modular Network Tested in C ++ (OMNeT ++, un simulador de redes que permite simular escenarios V2X) con el Car Learning to Act (CARLA, un simulador de conducción autónoma), transmitiendo los mensajes simulados con el OMNeT ++ hacia el CARLA. De esta manera el vehículo egocéntrico es más consciente de su entorno. El segundo objetivo ha sido evaluar la efectividad del servicio básico de Conciencia cooperativa (CA) mediante un simulador IEEE 802.11p V2X. Las simulaciones se han ejecutado variando la densidad de vehículos y los tamaños de los Mensajes de Concència Cooperativa (CAM) en dos escenarios diferentes: una autopista y una cuadrícula de Manhattan. El rendimiento ha sido evaluado analizando la Tasa de Paquetes erróneos (PER) y el número de mensajes recibidos en los dos escenarios. En el caso de la cuadrícula de Manhattan también se ha diferenciado el caso de Vista Directa (LOS). La presencia de más vehículos ha causado más pérdidas de paquetes debido al incremento de la interferencia y la probabilidad de colisiones de paquetes, incrementando así los valores de la PER. En el momento que se ha aumentado el tamaño de los mensajes CAM, la PER también ha aumentado, ya que las interferencias de los escenarios han aumentando. En el escenario de Manhattan hay un pico de más paquetes recibidos y más interferencias en las intersecciones, lo que conlleva un incremento de la PER.Un dels aspectes claus de la comunicació entre Vehicles cap a Tot (V2X) és el concepte de la consciència cooperativa, on l'intercanvi periòdic de l'estat de les informacions permet als vehicles ser conscients del seu entorn augmentant així la seguretat i l'eficàcia del trànsit. Aquest projecte consta de dos objectius, el primer ha estat implementar i dissenyar una interfície per comunicar l'Objective Modular Network Tested in C++ (OMNeT++, un simulador de xarxes que permet simular escenaris V2X) amb el Car Learning to Act (CARLA, un simulador de conducció autònoma), transmetent els missatges simulats amb l'OMNeT++ cap al CARLA. D'aquesta manera el vehicle egocèntric és més conscient del seu entorn. El segon objectiu ha estat avaluar l'efectivitat del servei bàsic de Conciència cooperativa (CA) mitjançant un simulador IEEE 802.11p V2X. Les simulacions s'han executat variant la densitat de vehicles i les mides dels Missatges de Conciència Cooperativa (CAM) en dos escenaris diferents: una autopista i una quadrícula de Manhattan. El rendiment ha estat avaluat analitzant la Tassa de Paquets Erronis (PER) i el nombre de missatges rebuts en els dos escenaris. En el cas de la quadrícula de Manhattan també s'ha diferenciat el cas de Vista Directa (LOS). La presència de més vehicles ha causat més pèrdues de paquets a causa de l'increment de la interferència i la probabilitat de col·lisions de paquets, incrementant així els valors de la PER. En el moment que s'ha augmentat la mida dels missatges CAM, la PER també ha augmentat, ja que les interferències dels escenaris han augmentant. A l'escenari de Manhattan hi ha un pic de més paquets rebuts i més interferències a les interseccions, la qual cosa comporta un increment de la PER.A key aspect of Vehicle-to-Everything (V2X) communication is the concept of cooperative awareness, wherein the periodic exchange of status information allows vehicles to become aware of their surroundings for increased traffic safety and efficiency. This project aimed to implement and design an interface to communicate the Objective Modular Network Tested in C++ (OMNeT++, a network simulator simulating V2X scenarios), with the Car Learning to Act (CARLA, an autonomous driver simulator), feeding the messages received from the OMNeT++ simulation to CARLA. This way, being the Ego vehicle more aware of their surroundings. This project also aimed to evaluate the effectiveness of the Cooperative awareness (CA) basic service through the development of an IEEE 802.11p-based V2X system simulator. The simulations were executed varying the density of vehicles and Cooperative Awareness Message (CAM)'s length in two different scenarios: the highway scenario and the Manhattan grid scenario. The performance was then assessed by analyzing the Packet Error Rate (PER), the number of messages received, and also, in the Manhattan scenario, differentiating the Line of Sight (LOS) cases. The presence of more vehicles caused higher packet losses due to increased interference and collisions probability, leading to higher PER values. When the CAM's length increased, the PER as well as the interference in the scenario increased. In the Manhattan scenarios a peak of more packets received and more interference was present in the intersections, leading to a higher PER values

The CUAVA-1 CubeSat—A Pathfinder Satellite for Remote Sensing and Earth Observation

In this paper we report a 3U CubeSat named CUAVA-1 designed by the ARC Training Centre for CubeSats, UAVs, and Their Applications (CUAVA). CUAVA, funded by the Australian Research Council, aims to train students, develop new instruments and technology to solve crucial problems, and help develop a world-class Australian industry in CubeSats, UAVs, and related products. The CUAVA-1 project is the Centre’s first CubeSat mission, following on from the 2 Australian satellites INSPIRE-2 and UNSW-EC0 CubeSats that launched in 2017. The mission is designed to serve as a precursor for a series of Earth observations missions and to demonstrate new technologies developed by our partners. We also intend to use the satellite to provide students hands-on experiences and to gain experience for our engineering, science and industry teams for future, more complex, missions

High-speed civil transport flight- and propulsion-control technological issues

Technology advances required in the flight and propulsion control system disciplines to develop a high speed civil transport (HSCT) are identified. The mission and requirements of the transport and major flight and propulsion control technology issues are discussed. Each issue is ranked and, for each issue, a plan for technology readiness is given. Certain features are unique and dominate control system design. These features include the high temperature environment, large flexible aircraft, control-configured empennage, minimizing control margins, and high availability and excellent maintainability. The failure to resolve most high-priority issues can prevent the transport from achieving its goals. The flow-time for hardware may require stimulus, since market forces may be insufficient to ensure timely production. Flight and propulsion control technology will contribute to takeoff gross weight reduction. Similar technology advances are necessary also to ensure flight safety for the transport. The certification basis of the HSCT must be negotiated between airplane manufacturers and government regulators. Efficient, quality design of the transport will require an integrated set of design tools that support the entire engineering design team