121 research outputs found

    Design And Development Of A Secure Wireless System Using Frequency Hopping Spread Spectrum [TK5103.2. A148 2007 f rb].

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    Dalam penyelidikan ini, satu sistem tanpa wayar automasi untuk menghantar data yang bersertakan kod PN secara automatik kepada pihak berkuasa berkenaan telah dibangunkan. In this research, an automated wireless system that sends the data accompanied with PN code automatically to the concerned authorities has been developed

    Orbiter global positioning system design and Ku-band problem investigations, exhibit B, revision 1

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    The hardware, software, and interface between them was investigated for a low dynamics, nonhostile environment, low cost GPS receiver (GPS Z set). The set is basically a three dimensional geodetic and way point navigator with GPS time, ground speed, and ground track as possible outputs in addition to the usual GPS receiver set outputs. Each functional module comprising the GPS set is described, enumerating its functional inputs and outputs, leading to the interface between hardware and software of the set

    Jammers for mobile cellular systems applied to unauthorized UAVs

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    This research aims to explore jamming on digital mobile systems, with an initial focus towards the 2G and Global System of Mobile Communications (GSM) technologies. The main goal is to develop a jammer with an efficiency and complexity greater than the existent ones, capable to better disrupt digital mobile systems. The study consists of an analysis of the different techniques of jamming, that can disrupt the mobile cellular system’s communication, through a series of simulations using the Software Defined Radio (SDR) and the GNU Radio ecosystem. The same techniques will then be studied and evaluated in real life scenarios in order to select which one is the best regarding spectral efficiency, energy and complexity. Finally, the jammer returning the best results will be the one chosen to contribute sustainably for the issue with flying drones on restrict areas, such as airports and residential zones, and thus, decrease the number of accidents which nowadays happen usually with this kind of aircrafts.Neste estudo será feita uma abordagem ao jamming em sistemas móveis digitais, dando um maior foco inicial à tecnologia 2G, Sistema Global para Comunicações Móveis (GSM). O objetivo principal será o desenvolvimento de um sinal jammer, diferente dos já existentes em termos de eficiência e complexidade, capaz de causar interferência em sistemas móveis celulares. Será feito então uma análise às diferentes técnicas de interferência de sinal, capazes de perturbar a comunicação em sistemas móveis celulares, através da realização de simulações a partir da tecnologia Software Defined Radio (SDR) nomeadamente, a plataforma GNU Radio. As mesmas técnicas também serão estudadas e avaliadas num cenário real, de forma a fazer-se a seleção da melhor em termos de eficiência espectral, energia e complexidade. Finalmente, a técnica de jamming que demonstrar melhores resultados, irá representar o jammer que poderá contribuir de forma sustentável para a problemática da circulação de drones em zonas restritas, como aeroportos e zonas residenciais, para a diminuição dos acidentes, atualmente registados, com este tipo de aeronaves

    Wideband cyclostationary spectrum sensing and characterization for cognitive radios

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    Motivated by the spectrum scarcity problem, Cognitive Radios (CRs) have been proposed as a solution to opportunistically communicate over unused spectrum licensed to Primary users (PUs). In this context, the unlicensed Secondary users (SUs) sense the spectrum to detect the presence or absence of PUs, and use the unoccupied bands without causing interference to PUs. CRs are equipped with capabilities such as, learning, adaptability, and recongurability, and are spectrum aware. Spectrum awareness comes from spectrum sensing, and it can be performed using different techniques

    REDESIGNING THE COUNTER UNMANNED SYSTEMS ARCHITECTURE

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    Includes supplementary material. Please contact [email protected] for access.When the Islamic State used Unmanned Aerial Vehicles (UAV) to target coalition forces in 2014, the use of UAVs rapidly expanded, giving weak states and non-state actors an asymmetric advantage over their technologically superior foes. This asymmetry led the Department of Defense (DOD) and the Department of Homeland Security (DHS) to spend vast sums of money on counter-unmanned aircraft systems (C-UAS). Despite the market density, many C-UAS technologies use expensive, bulky, and high-power-consuming electronic attack methods for ground-to-air interdiction. This thesis outlines the current technology used for C-UAS and proposes a defense-in-depth framework using airborne C-UAS patrols outfitted with cyber-attack capabilities. Using aerial interdiction, this thesis develops a novel C-UAS device called the Detachable Drone Hijacker—a low-size, weight, and power C-UAS device designed to deliver cyber-attacks against commercial UAVs using the IEEE 802.11 wireless communication specification. The experimentation results show that the Detachable Drone Hijacker, which weighs 400 grams, consumes one Watt of power, and costs $250, can interdict adversarial UAVs with no unintended collateral damage. This thesis recommends that the DOD and DHS incorporates aerial interdiction to support its C-UAS defense-in-depth, using technologies similar to the Detachable Drone Hijacker.DASN-OE, Washington DC, 20310Captain, United States Marine CorpsApproved for public release. Distribution is unlimited

    Effectiveness of Electronic Counter Measures (ECM) on Small Unmanned Aerial Systems (SUAS): Analysis and Preliminary Tests

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    Small unmanned aerial systems (sUAS) have become more common and affordable for government, commercial, and private use. There are several counter sUAS products that employ electromagnetic counter measures to disrupt the communications link of sUAS. However, most of these solutions are limited in efficacy to specific sUAS types due to the sophisticated control and communications link technologies utilized by sUAS which make it challenging to effectively jam. To address these challenges, a Drone Detection and Mitigation Radar (DDMR) concept was developed. The jamming component of the DDMR used wideband noise combined with random sweeping of the noise to jam the communications link. This thesis research was predicated by a laboratory experiment which used the DDMR system to successfully jam an sUAS’s communications link. This particular experiment did not (1) provide any theoretical analysis, (2) simulation analysis to determine the effective jamming probabilities, or (3) conduct additional experiments to find the optimal sweeping frequency for the jamming component of the DDMR. This thesis focuses on the optimization of the sweeping noise jamming solution of the communications link by examining the theoretical and simulation analysis as well as the results of further experimental studies. The findings are presented in this thesis paper

    Performance Study of Hybrid Spread Spectrum Techniques

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    This thesis focuses on the performance analysis of hybrid direct sequence/slow frequency hopping (DS/SFH) and hybrid direct sequence/fast frequency hopping (DS/FFH) systems under multi-user interference and Rayleigh fading. First, we analyze the performance of direct sequence spread spectrum (DSSS), slow frequency hopping (SFH) and fast frequency hopping (FFH) systems for varying processing gains under interference environment assuming equal bandwidth constraint with Binary Phase Shift Keying (BPSK) modulation and synchronous system. After thorough literature survey, we show that hybrid DS/FFH systems outperform both SFH and hybrid DS/SFH systems under Rayleigh fading and multi-user interference. Also, both hybrid DS/SFH and hybrid DS/FFH show performance improvement with increasing spreading factor and decreasing number of hopping frequencies

    Reducing Asymmetry in Countering Unmanned Aerial Systems

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    Excerpt from the Proceedings of the Nineteenth Annual Acquisition Research SymposiumCurrent Counter Unmanned Aerial Systems (C-UAS) rely heavily on low-efficiency techniques such as broadband radio frequency (RF) jamming and high-intensity lasers. Not only do such techniques come at the cost of second and third order effects—such as collateral jamming risks to operational systems, a large RF footprint, and high energy use—but they also present an asymmetry between threat and response. Many commercial, off-the-shelf UAS devices are inexpensive compared to the C-UAS systems historically under focus in Department of Defense (DoD) acquisition. This work argues for leveling that asymmetry by exploring C-UAS autonomy-on-autonomy options by using cyberattack payload capabilities residing on a UAS. By reducing the attack surface to focus on a particular target, these cyber techniques provide scalpel-edged control to the operator, reducing risk to own systems, RF footprint, and collateral damage.Approved for public release; distribution is unlimited
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