Dissertations / Theses on the topic 'On-board system design'

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California<br>On reviewing current PCM on-board data acquisition systems design is not very uncommon to find lots of useful signals being generated together with the PCM stream, such as bit clocks, word clocks, minor and major frame pulses. The purpose of this paper is to demonstrate a conceptual design of a digital recording device that takes advantage of these signals to collect data directly into a computer compatible disk file. Such device can eliminate the need of further PCM signal processing after the test and speed up the conversion process of pure digital sampling values into floating point numbers.

Thesis (MEng)--University of Stellenbosch, 2000.<br>ENGLISH ABSTRACT: Satellites are not all made equal. The large number of possible orbits, desired functionality and budget constraints are but a few of the factors that influence the design of a satellite. Given a particular set of design requirements, a number of designs may meet these requirements. Each of these designs will typically entail a trade-off between a number of (conflicting) parameters, whilst still satisfying the system requirements. The On-Board Computer (OBC) of a satellite, the satellite subsystem primarily responsible for the operational control of a satellite, can consequently be designed in any of a number of different ways. As the factors that influence the flight performance of an OBC differs to those of a terrestrial computer, the OBC design will therefore be significantly different. A high-level overview of the factors that impact OBC design and operation is presented. Improvements to the existing designs are proposed. In conclusion, a number of guidelines for a future OBC design also are given.<br>AFRIKAANSE OPSOMMING: Elke satelliet het unieke eienskappe wat bepaal word deur onderandere, die teiken wentelbaan, verwagte funksionaliteit en koste oorweegings. Vir 'n spesefieke stelselontwerp bestaan daar 'n aantal moontlike ontwerpe wat aan die stelsel vereistes voldoen. Elk van hierdie ontwerpe sal tipies behels dat verskillende parameters teen mekaar afgespeel word, terwyl die stelsel vereistes steeds aan voldoen word. Die Aanboord Rekenaar (AR) van 'n satelliet, die satelliet substelsel hoofsaaklik verantwoordelik vir die beheer van die satelliet, kan vervolgens uit een van veele moontlike ontwerpe bestaan. Aangesien die faktore wat die werkverrigting van 'n AR beinvloed verskil van die van 'n rekenaar wat op die aard oppervlak gebruik word, sal die AR ontwerp dienooreenkomstig verskil. 'n Hoevlak oorsig van die faktore wat AR ontwerp beinvloed sal gegee word. Verbeteringe wat aan die huidige AR ontwerpe gedoen kan word sal bespreek word. Ter afsluiting sal 'n aantal riglyne vir toekomstige AR ontwerpe gegee word.

Future spacecrafts will require more computational and processing power to keep up with the growing demand in requirements and complexity. ScOSA is the next generation on-board computer developed by the German Aerospace Centre (DLR). The main motivation behind ScOSA is to replace the conventional on-board computer with distributed and reconfigurable computing nodes which provides higher performance, reliability, availability and stability by using a combination of the COTS components and reliable computing processors that are space qualified. In the current ScOSA system reconfiguration and routing of data between nodes are based on a static decision graph. SpaceWire protocol is used to communicate between nodes to provide reliability. The focus of the thesis is to design and implement a dynamic routing protocol for ScOSA which can be used in future for not only communicating between the nodes but also for reconfiguration. SpaceWire IPC is a customized protocol developed by DLR to provide communication between the nodes in a distributed network and to support monitoring, management and reconfiguration services. The dynamic routing protocol proposed in this thesis is primarily derived from the monitoring mechanism used in the SpaceWire IPC. PULL type monitoring mechanism is modelled and simulated using OMNeT++. The results obtained provide a qualitative outlook of the dynamic routing protocol implemented.

This research programme has studied the possibilities and difficulties of using 50 kg microsatellites to perform remote imaging of the Earth. The design constraints of these missions are quite different to those encountered in larger, conventional spacecraft. While the main attractions of microsatellites are low cost and fast response times, they present the following key limitations: Payload mass under 5 kg, Continuous payload power under 5 Watts, peak power up to 15 Watts, Narrow communications bandwidths (9.6 / 38.4 kbps), Attitude control to within 5&deg;, No moving mechanics. The most significant factor is the limited attitude stability. Without sub-degree attitude control, conventional scanning imaging systems cannot preserve scene geometry, and are therefore poorly suited to current microsatellite capabilities. The foremost conclusion of this thesis is that electronic cameras, which capture entire scenes in a single operation, must be used to overcome the effects of the satellite's motion. The potential applications of electronic cameras, including microsatellite remote sensing, have erupted with the recent availability of high sensitivity field-array CCD (charge-coupled device) image sensors. The research programme has established suitable techniques and architectures necessary for CCD sensors, cameras and entire imaging systems to fulfil scientific/commercial remote sensing despite the difficult conditions on microsatellites. The author has refined these theories by designing, building and exploiting in-orbit five generations of electronic cameras. The major objective of meteorological scale imaging was conclusively demonstrated by the Earth imaging camera flown on the UoSAT-5 spacecraft in 1991. Improved cameras have since been carried by the KITSAT-1 (1992) and PoSAT-1 (1993) microsatellites. PoSAT-1 also flies a medium resolution camera (200 metres) which (despite complete success) has highlighted certain limitations of microsatellites for high resolution remote sensing. A reworked, and extensively modularised, design has been developed for the four camera systems deployed on the FASat-Alfa mission (1995). Based on the success of these missions, this thesis presents many recommendations for the design of microsatellite imaging systems. The novelty of this research programme has been the principle of designing practical camera systems to fit on an existing, highly restrictive, satellite platform, rather than conceiving a fictitious small satellite to support a high performance scanning imager. This pragmatic approach has resulted in the first incontestable demonstrations of the feasibility of remote sensing of the Earth from inexpensive microsatellites.

碩士<br>淡江大學<br>航空太空工程學系<br>92<br>This thesis discusses the design of a power management system for a solar powered uninhabited air vehicle. The power management system provides the required power for the propeller and on board computer systems and monitors the health and the availability of the power source. The system consists of three major stages, namely, the maximum power tracking stage, the Li-ion battery charge/discharge management stage, and the power converting stage. The design results will be evaluated on a solar powered uninhabited air vehicle.

碩士<br>國立成功大學<br>交通管理學系碩博士班<br>91<br>Due to fast growth of motorized vehicles, various traffic problems occur. Therefore, most countries around the world develop intelligent transportation systems (ITS) to resolve these problems. ITS applies information technology and communication networks to assist drivers for a safer and more efficient travel. Many driving simulator systems have been constructed worldwide in recent years. The application of driving simulator systems leads to the building of an analysis platform to evaluate ITS. The driving simulator systems not only help drivers from a fundamental perspective of traffic safety, but also help to practice ITS environment. As for these concerns, this study aims to the main causes of accidents in Taiwan to develop suitable warning systems on board (overspeed, obstacle, collision, car-following). This study understands drivers’ action by applying driving simulator systems and investigates drivers’ perception by questionnaires. It is expected to integrate subjective and objective perspectives to establish the suitable products of warning systems. The experimental results show the information provided by warning systems is needed and different types of warning don’t influence drivers obviously. Besides, the results of questionnaires show the purchasing intentions increase. This means the drivers understand the efficiency of warning systems after simulation experiments. In the near future driving simulator systems will be ready to help manufacture the suitable warning systems in Taiwan to enhance traffic safety.

碩士<br>國立成功大學<br>電機工程學系碩博士班<br>91<br>Currently, manufacturing of electronic circuits, including printed circuit board (PCB), has been playing an important role in the light industry. Since most appliances are made of circuit elements, which are arranged on PCB, the manufacturing of the printed circuit board has become an important branch of electronic industry. The quality control of PCB on a production line is an essential work, however, because of the huge quantity of the production of PCB, detecting the defects on PCB with human eyes can not get a good efficiency. Thus the automatic detecting system is developed. The defect detection system can be divided mainly into two units: image acquisition and image processing.In image acquisition unit, the pre-detecting product is placed under a video camera in which images are obtained and sent to the processing unit (here, analog image signal is converted to digital image signal). In the image processing unit, quality identification is done on the product according to the input digital image signal, however, before this action, pattern of copper foil of the PCB should be acquired, therefore if there is any defect or fault on the copper foil printing, it can be recognized. This thesis is aimed at the study of the automatic copper foil acquisition system. Personal computers (PCs) are applied to most of the automatic identification systems as processing units.However, PC is large in size, operating system and other application software are required, so it causes a higher cost, it is not well to apply on an industrial production line. The aim of this study is to develop a tiny independent system with the application of low cost filed programmable fate arrays (FPGA). It is suitable for mass production, owning to the saving of software and applying of low cost FPGA. And it is more corresponding with practical and commercial purpose.

碩士<br>健行科技大學<br>電機工程系碩士班<br>104<br>The clock on PCB design is increased rapidly, thus design is more and more difficult. How to reduce the signal reflection, crosstalk, ringing on transmission line? These issues have been paid more and more attention. The operation speed on Data bus between CPU and memory is often the highest part of the system. This also causes the system design becoming one of the most difficult subjects. There is a big change in the design from the SDRAM generation to the DDR SDRAM generation. Data is got once in a cycle change to be got two times in a cycle.That is, the fetch number of DDR SDRAM DATA will be two times the traditional SDRAM in the same clock. The topology architecture on DDR2 and DDR3 have been changed from T-topology to Fly-by topology. Meanwhile, the changes on the architecture from DDR3 to DDR4 are designed by Bank Group and POD. Because of that, the effectiveness of DDR4 have been improved greatly. Also, it started a whole new generation on memory. The alternation of generations change hardware and architecture to achieve best performance and lower working voltage. However, these changes make the process of PCB design more complicated and challenging. Nevertheless, memory is single element after all, compatibility on design and layout between other elements should be considered. Therefore, aside from undergoing stimulation analysis on the layout of memory, other elements should be adjusted and stimulated analysis at the same time to reach a better signal integrity. A prevalent product design architecture is memory module. This can make the design more flexible. Yet this brought about the problems on the connection between main board and daughter board. In this paper, we will use Xilinx Virtex-7 development board VC709 as main board, and Micron memory module DDR3 SO-DIMM as daughter board. Also,the context discusses the issues of memory layout design , connection between FPGA and memory, and it’s signal integrity by DesignLink in Allegro Cadence 16.5 SI.