129 research outputs found

    Implementation of E-education in Africa via Space Networks

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    In this paper is introduced an advanced E-education provision in remote dispersed communities, such as rural, remote, mobile, agriculture, mining, construction, surveying, military, tourism and so on, based on the specific needs and requirements, implies significant broadband connectivity requirements, timely and quality-assured content delivery of service, applications and interactivity. The E-education solutions of distance learning and training for remote and rural areas, which are out of range of terrestrial and short distance wireless telecommunications facilities, cannot provide the broadband access without space-enabled communication infrastructures, such as satellite constellations and Stratospheric Platform Systems (SPS) or High Altitude Platforms (HAP). The paper also discusses the integration challenges that are presented by combining use of the space solutions for implementation Education and learning in urban, rural and mobile environments. The configuration of in-house design and development of Space Segment, installation of the scale-down Digital Video Broadcasting-Return Channel via Satellite (DVB-RCS) Hub as a Gateway, Ground Network and Interactive VSAT, known as Fixed Interactive Terminals (FIT), for E-education, distance learning and staff training initiative in Africa are described

    Software support for video streaming from smartphone on small airship

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    This project has been created to study and to solve two goals. The main goal has been streaming real video from a smartphone to a laptop and the second goal has been to control the airship electronics from the smartphone. To achieve the main goal of the project, firstly has been necessary realize a technologies study to select the better choice. The chosen technology has been to use of wi-fi, mainly due to the high transmission speed. Once the technology has been chosen, an ad-hoc wi-fi network has been created to be able to transmit wirelessly. After that, it has been necessary to study how to do the sending of the information. The first idea was using the User Datagram Protocol or Transport Control Protocol, at the beginning it seemed a good choice, because of was possible to achieve a communication between the smartphone and the laptop and a camera in record mode application was created. However, when the real video was to be sent to the laptop, it was not possible because it was not way to open the file while it was been created and there was not any temporal file. Then, another possibility had to be studied and it was the use of streamers. The Live555 Streaming Media is a set of C++ libraries which allows to stream real time from a device to a computer. After the hard work to run this application, it was running fine on the laptop, as well as, the laptop’s webcam was working fine. However, after try to develop a smartphone’s application was discovered that these libraries are not support for Windows Mobile. Therefore, a new way was discovered, the use of DirectShow which is architecture for streaming media, it seemed would work fine, but after the difficulty to compile a code, the smartphone was not detected and there weren’t so much information about how to solve the related problems. Finally, a real time software has been used to stream real video from the smartphone to a laptop. There have been two possibilities, Qik or AtekSoft Web CameraPlus. However, the second one was descarted due to the obligation to pay for use the software. The second goal was studied to develop a serial port application to be used by Infra Red port. However, it was possible that smartphone wouldn’t have IR Port, so a second alternative was studied and it was using the mini USB connection to achieve through a mini USB to USB adapter and an USB to serial port converter to communicate using serial port communication, but this possibility was not support by Windows Mobile. Then, a possible solution is described, it is using the smartphone like an USB device and on the other side (electronics) the use of an USB host and through drivers allows the communication. The smartphone used has been HTC Touch 3G which uses Windows Mobile 6.1 Operative System. The laptop used has been Dell XPS M1330, which uses Windows Vista Operative System the programming software has been Visual Studio 2008. In conclusion, the project has helped me to improve knowledge, on the one hand in my studies and on the other hand in my foreign language. It has been a good experience to work in a real project in the RDC department

    Ultra-Fast, Autonomous, Reconfigurable Communication System

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    The recent years have witnessed an increase in natural disasters in which the destruction of essential communication infrastructure has significantly affected the number of casualties. In 2005, Hurricane Katrina in the United States resulted in over 1,900 deaths, three million land-line phones disconnections, and more than 2000 cell sites going out of service. This incident highlighted an urgent need for a quick-deployment, efficient communication network for emergency relief purposes. In this research, a fully autonomous system to deploy Unmanned Aerial Vehicles (UAVs) as the first phase disaster recovery communication network for wide-area relief is presented. As part of this system, an automation algorithm has been developed to control the deployment and positioning of the UAVs based on a traditional cell network structure utilizing 7-cell clusters in a hexagonal pattern. In addition to the software algorithm, a fully functional control interface was developed which allowed for full control of the system both locally and over an internet connection. This system represents a novel approach for handling a large-scale autonomous deployment of a UAV communications networks

    Tier-scalable reconnaissance: the challenge of sensor optimization, sensor deployment, sensor fusion, and sensor interoperability

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    Robotic reconnaissance operations are called for in extreme environments, not only those such as space, including planetary atmospheres, surfaces, and subsurfaces, but also in potentially hazardous or inaccessible operational areas on Earth, such as mine fields, battlefield environments, enemy occupied territories, terrorist infiltrated environments, or areas that have been exposed to biochemical agents or radiation. Real time reconnaissance enables the identification and characterization of transient events. A fundamentally new mission concept for tier-scalable reconnaissance of operational areas, originated by Fink et al., is aimed at replacing the engineering and safety constrained mission designs of the past. The tier-scalable paradigm integrates multi-tier (orbit atmosphere surface/subsurface) and multi-agent (satellite UAV/blimp surface/subsurface sensing platforms) hierarchical mission architectures, introducing not only mission redundancy and safety, but also enabling and optimizing intelligent, less constrained, and distributed reconnaissance in real time. Given the mass, size, and power constraints faced by such a multi-platform approach, this is an ideal application scenario for a diverse set of MEMS sensors. To support such mission architectures, a high degree of operational autonomy is required. Essential elements of such operational autonomy are: (1) automatic mapping of an operational area from different vantage points (including vehicle health monitoring); (2) automatic feature extraction and target/region-of-interest identification within the mapped operational area; and (3) automatic target prioritization for close-up examination. These requirements imply the optimal deployment of MEMS sensors and sensor platforms, sensor fusion, and sensor interoperability

    Contributions to channel modelling and performance estimation of HAPS-based communication systems regarding IEEE Std 802.16TM

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    New and future telecommunication networks are and will be broadband type. The existing terrestrial and space radio communication infrastructures might be supplemented by new wireless networks that make and will make use of aeronautics-technology. Our study/contribution is referring to radio communications based on radio stations aboard a stratospheric platform named, by ITU-R, HAPS (High Altitude Platform Station). These new networks have been proposed as an alternative technology within the ITU framework to provide various narrow/broadband communication services. With the possibility of having a payload for Telecommunications in an aircraft or a balloon (HAPS), it can be carried out radio communications to provide backbone connections on ground and to access to broadband points for ground terminals. The latest implies a complex radio network planning. Therefore, the radio coverage analysis at outdoors and indoors becomes an important issue on the design of new radio systems. In this doctoral thesis, the contribution is related to the HAPS application for terrestrial fixed broadband communications. HAPS was hypothesised as a quasi-static platform with height above ground at the so-called stratospheric layer. Latter contribution was fulfilled by approaching via simulations the outdoor-indoor coverage with a simple efficient computational model at downlink mode. This work was assessing the ITU-R recommendations at bands recognised for the HAPS-based networks. It was contemplated the possibility of operating around 2 GHz (1820 MHz, specifically) because this band is recognised as an alternative for HAPS networks that can provide IMT-2000 and IMT-Advanced services. The global broadband radio communication model was composed of three parts: transmitter, channel, and receiver. The transmitter and receiver parts were based on the specifications of the IEEE Std 802.16TM-2009 (with its respective digital transmission techniques for a robust-reliable link), and the channel was subjected to the analysis of radio modelling at the level of HAPS and terrestrial (outdoors plus indoors) parts. For the channel modelling was used the two-state characterisation (physical situations associated with the transmitted/received signals), the state-oriented channel modelling. One of the channel-state contemplated the environmental transmission situation defined by a direct path between transmitter and receiver, and the remaining one regarded the conditions of shadowing. These states were dependent on the elevation angle related to the ray-tracing analysis: within the propagation environment, it was considered that a representative portion of the total energy of the signal was received by a direct or diffracted wave, and the remaining power signal was coming by a specular wave, to last-mentioned waves (rays) were added the scattered and random rays that constituted the diffuse wave. At indoors case, the variations of the transmitted signal were also considering the following matters additionally: the building penetration, construction material, angle of incidence, floor height, position of terminal in the room, and indoor fading; also, these indoors radiocommunications presented different type of paths to reach the receiver: obscured LOS, no LOS (NLOS), and hard NLOS. The evaluation of the feasible performance for the HAPS-to-ground terminal was accomplished by means of thorough simulations. The outcomes of the experiment were presented in terms of BER vs. Eb/N0 plotting, getting significant positive conclusions for these kind of system as access network technology based on HAPS

    High Intensity Laser Power Beaming for Wireless Power Transmission

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    This paper describes work supporting the development of a high intensity laser power beaming (HILPB) system for the purpose of wireless power transmission. The main contribution of this research is utilizing high intensity lasers to illuminate vertical multi-junction (VMJ) solar cells developed by NASA-GRC. Several HILPB receivers are designed, constructed and evaluated with various lasers to assess the performance of the VMJ cells and the receiver under a variety of conditions. Several matters such as parallel cell back-feeding, optimal receiver geometry, laser wavelength, non-uniform illumination and thermal effects at high intensities are investigated. Substantial power densities are achieved, and suggestions are made to improve the performance of the system in future iterations. Thus far, the highest amount of energy obtained from a receiver during these tests was 23.7778 watts. In addition, one VMJ cell was able to achieve a power density of 13.6 watts per cm2, at a conversion efficiency of 24 . These experiments confirm that the VMJ technology can withstand and utilize the high intensity laser energy without damage and/or significant reduction in the conversion efficienc

    High Intensity Laser Power Beaming for Wireless Power Transmission

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    This paper describes work supporting the development of a high intensity laser power beaming (HILPB) system for the purpose of wireless power transmission. The main contribution of this research is utilizing high intensity lasers to illuminate vertical multi-junction (VMJ) solar cells developed by NASA-GRC. Several HILPB receivers are designed, constructed and evaluated with various lasers to assess the performance of the VMJ cells and the receiver under a variety of conditions. Several matters such as parallel cell back-feeding, optimal receiver geometry, laser wavelength, non-uniform illumination and thermal effects at high intensities are investigated. Substantial power densities are achieved, and suggestions are made to improve the performance of the system in future iterations. Thus far, the highest amount of energy obtained from a receiver during these tests was 23.7778 watts. In addition, one VMJ cell was able to achieve a power density of 13.6 watts per cm2, at a conversion efficiency of 24 . These experiments confirm that the VMJ technology can withstand and utilize the high intensity laser energy without damage and/or significant reduction in the conversion efficienc
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