290 research outputs found

    Satellite power system: Concept development and evaluation program. Volume 3: Power transmission and reception. Technical summary and assessment

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    Efforts in the DOE/NASA concept development and evaluation program are discussed for the solar power satellite power transmission and reception system. A technical summary is provided together with a summary of system assessment activities. System options and system definition drivers are described. Major system assessment activities were in support of the reference system definition, solid state system studies, critical technology supporting investigations, and various system and subsystem tradeoffs. These activities are described together with reference system updates and alternative concepts for each of the subsystem areas. Conclusions reached as a result of the numerous analytical and experimental evaluations are presented. Remaining issues for a possible follow-on program are identified

    Detecting and locating electronic devices using their unintended electromagnetic emissions

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    Electronically-initiated explosives can have unintended electromagnetic emissions which propagate through walls and sealed containers. These emissions, if properly characterized, enable the prompt and accurate detection of explosive threats. The following dissertation develops and evaluates techniques for detecting and locating common electronic initiators. The unintended emissions of radio receivers and microcontrollers are analyzed. These emissions are low-power radio signals that result from the device\u27s normal operation. In the first section, it is demonstrated that arbitrary signals can be injected into a radio receiver\u27s unintended emissions using a relatively weak stimulation signal. This effect is called stimulated emissions. The performance of stimulated emissions is compared to passive detection techniques. The novel technique offers a 5 to 10 dB sensitivity improvement over passive methods for detecting radio receivers. The second section develops a radar-like technique for accurately locating radio receivers. The radar utilizes the stimulated emissions technique with wideband signals. A radar-like system is designed and implemented in hardware. Its accuracy tested in a noisy, multipath-rich, indoor environment. The proposed radar can locate superheterodyne radio receivers with a root mean square position error less than 5 meters when the SNR is 15 dB or above. In the third section, an analytic model is developed for the unintended emissions of microcontrollers. It is demonstrated that these emissions consist of a periodic train of impulses. Measurements of an 8051 microcontroller validate this model. The model is used to evaluate the noise performance of several existing algorithms. Results indicate that the pitch estimation techniques have a 4 dB sensitivity improvement over epoch folding algorithms --Abstract, page iii

    Design and Development of a Multi-Purpose Input Output Controller Board for the SPES Control System

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    This PhD work has been carried out at the Legnaro National Laboratories (LNL), one of the four national labs of the National Institute for Nuclear Physics (INFN). The mission of LNL is to perform research in the field of nuclear physics and nuclear astrophysics together with emerging technologies. Technological research and innovation are the key to promote excellence in science, to excite competitive industries and to establish a better society. The research activities concerning electronics and computer science are an essential base to develop the control system of the Selective Production of Exotic Species (SPES) project. Nowadays, SPES is the most important project commissioned at LNL and represents the future of the Lab. It is a second generation Isotope Separation On-Line (ISOL) radioactive ion beam facility intended for fundamental nuclear physics research as well as experimental applications in different fields of science, such as nuclear medicine; radio-pharmaceutical production for therapy and diagnostic. The design of the SPES control system demands innovative technologies to embed the control of several appliances with different requirements and performing different tasks spanning from data sharing and visualization, data acquisition and storage, networking, security and surveillance operations, beam transport and diagnostic. The real time applications and fast peripherals control commonly found in the distributed control network of particle accelerators are accompanied by the challenge of developing custom embedded systems. In this context, the proposed PhD work describes the design and development of a multi-purpose Input Output Controller (IOC) board capable of embedding the control of typical accelerator instrumentation involved in the automatic beam transport system foreseen for the SPES project. The idea behind this work is to extend the control reach to the single device level without losing in modularity and standardization. The outcome of the research work is a general purpose embedded computer that will be the base for standardizing the hardware layer of the frontend computers in the SPES distributed control system. The IOC board is a Computer-on-Module (COM) carrier board designed to host any COM Express type 6 module and is equipped with a Field Programmable Gate Array (FPGA) and user application specific I/O connection solutions not found in a desktop pc. All the generic pc functionalities are readily available in off-the-shelf modules and the result is a custom motherboard that bridges the gap between custom developments and commercial personal computers. The end user can deal with a general-purpose pc with a high level of hardware abstraction besides being able to exploit the on-board FPGA potentialities in terms of fast peripherals control and real time digital data processing. This document opens with an introductory chapter about the SPES project and its control system architecture and technology before to describe the IOC board design, prototyping, and characterization. The thesis ends describing the installation in the field of the IOC board which is the core of the new diagnostics data readout and signal processing system. The results of the tests performed under real beam conditions prove that the new hardware extends the current sensitivity to the pA range, addressing the SPES requirements, and prove that the IOC board is a reliable solution to standardize the control of several appliances in the SPES accelerators complex where it will be embedded into physical equipment, or in their proximity, and will control and monitor their operation replacing the legacy VME technology. The installation in the field of the IOC board represents a great personal reward and crowns these years of busy time during which I turned what was just an idea in 2014, into a working embedded computer today

    Error handling and controller design for controller area network-based networked control system

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    Networked Control System (NCS) is a feedback control system which dynamic process is running via the communication channel. Surrounded by many choices of network types that can be used to establish an NCS, Controller Area Network (CAN) is a popular choice widely used in most real-time applications. Under harsh environment, fault at transmission line for CAN-based NCS is more prominent compared to fault in network nodes. Fault in bus line of CAN will induce data error which will result in data dropout or/and time delay which consequently lead to performance degradation or system instability. In this thesis, strategies to handle fault occurrence in CAN bus are proposed in order to properly analyse the effect of fault to CAN-based NCS performance. To implement the strategies, first, fault occurrences are modelled based on fault inter-arrival time, fault bursts duration and Poisson law. By using fault and message attributes, Response Time Analysis (RTA) is performed and the probability of NCS message that misses its deadline is calculated based on Homogeneous Poisson Process (HPP). A new error handling algorithm per-sample-error-counter (PSeC) is introduced to replace native error handling of CAN. PSeC mechanism is designed based on online monitoring and counting of erroneous sensor and control signal data at every sampling instance and it gives a bound parameters known as Maximum Allowable Number of Data Retransmission (MADR). If the number of retransmission for NCS message violates the value of MADR, the data will be discarded. With the utilization of PSeC mechanism to replace the Native Error Handling (NEH) of CAN, the probability of NCS message that misses its deadline can be translated to the probability of data dropout of NCS message. Despite the PSeC has prevented network from congestion which can lead to prolonged loop delay, it also introduces one-step loop delay and data dropout. Therefore, the controller that is able to compensate the effect of delay and data dropout should be introduced. Thus, a control algorithm is designed based on Lyapunov stability theory formulated in Linear Matrix Inequality (LMI) form by taking into account network delay and data dropout probability. In order to proof the efficacy of the strategies, Steer-by-Wire (SbW) system is used and simulated in TrueTime MATLAB R /Simulink environment. Simulation results show that the strategies of introducing PSeC mechanism and the designed controller in this work have superior performance than NEH mechanism for CAN-based NCS environment in terms of integral of the absolute error (IAE) and energy consumption

    Ultra wideband communication link

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    Ultra-wideband communication (UWB) has been a topic of extensive research in recent years especially for its short-range communication and indoor applications. The preliminary objective of the project was to develop a description and understanding of the basic components of the communication link at microwave frequencies in order to achieve the primary objective of establishing a communication setup at a bandwidth of 2.5 GHz for testing Ultra Wideband (UWB) antennas. This was achieved with the aid of commercially available optical system which was modified for the purpose. Beginning with the generation of baseband narrow pulses with energy spanning over a broad frequency range, through multiplexing of different parallel channels carrying these pulses into a single stream, to finally capturing the received signal to understand the effect of the communication link formed; all provided basis for identifying the issues and possible solutions to establishing a reliable communication link at UWB frequency

    System design and specifications. Earth Observatory Satellite system definition study (EOS)

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    A design summary of the Earth Observatory Satellite (EOS) is presented. The systems considered in the summary are: (1) the spacecraft structure, (2) electrical power modules, (3) communications and data handling module, (4) attitude determination module, (5) actuation module, and (6) solar array and drive module. The documents which provide the specifications for the systems and the equipment are identified
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