853 research outputs found

    A service-constrained positioning strategy for an autonomous fleet of airborne base stations

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    This paper proposes a positioning strategy for a fleet of unmanned aerial vehicles (UAVs) airlifting wireless base stations driven by communication constraints. First, two schedulers that model the distribution of resources among users within a single cell are analyzed. Then, an UAV autonomous positioning strategy is developed, based on a fair distribution of the radio resources among all the users of all the cells in a given scenario, in such a way that the user bitrate is the same regardless the users’ distribution and spatial density. Moreover, two realistic constraints are added related to capacity of the backhaul link among the UAVs and the ground station: the bitrate delivered per UAV and the total backhaul bandwidth shared among all the UAVs. Additionally, an energy consumption model is considered to evaluate the efficiency and viability of the proposed strategy. Finally, numerical results in different scenarios are provided to assess both the schedulers performance and the proposed coordinated positioning strategy for the UAVs.Peer ReviewedPostprint (published version

    WATER-BASED MITIGATION TECHNIQUES AND NETWORK INTEGRATION TO COUNTER DRONE SWARMS

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    Potential and current U.S. adversaries are purchasing and deploying commercial small Unmanned Aircraft Systems (sUAS) in networked swarms. These swarms can be used for intelligence collection and reconnaissance, and have the potential to be weaponized as well. Additionally, the unlawful, but probably not malicious, activity of civilian UAS (drone) operators is of increasing concern. More specifically, there is increased risk to naval assets while in constrained environments, such as harbor transit, where both navigation and weaponized responses are serious concerns. This thesis uses the scenario of protecting a U.S. Navy destroyer entering and exiting a harbor to develop a sUAS mitigation procedure based on existing firefighting and counter-piracy technologies. The proposed procedure includes a communications plan and can be implemented almost immediately using existing civilian and military assets. Additional recommendations to improve the performance of such procedures are provided.CRUSARRRTOLieutenant, United States NavyApproved for public release. Distribution is unlimited

    China Near Seas Combat Capabilities

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    The capstone U.S. Defense Department study on the future operational environment declares, China\u27s rise represents the most significant single event on the international horizon since the collapse of the Cold War. Understanding and assessing changes in China\u27s traditionally defensive naval strategy, doctrine, and force structure are of obvious importance to the U.S. Navy (USN) and other Pacific navies concerned with the possible security implications of that rise. This chapter examines the development of the Chinese navy\u27s Houbei (Type 022) fast-attack-craft force and its roles and missions in China\u27s near seas and discusses implications for the U.S. Navy and other navies in the region.https://digital-commons.usnwc.edu/cmsi-red-books/1010/thumbnail.jp

    Transport 2040 : analysis of technical developments in transport - maritime, air, rail and road

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    A number of technical and socio-technical factors are driving the development and adoption of automation. The report, Transport 2040: Automation, Technology, Employment – The Future of Work, provided an overview of the most important trends forecasted to affect the global transport sector by 2040. This current report provides additional details of that assessment. The research conducted is guided by a transport-technology analytical model that provides a structure for a systematic review across different modes of transport. This report reviews, in particular, the transportation technology through the lens of transport vehicles (e.g. ships, trucks, trains, aircraft) and the technical infrastructure that is needed for the operation of the vehicle (e.g. waterways and harbours, roads, railway tracks and freight terminals, as well as controlled airspace and airports).https://commons.wmu.se/lib_reports/1076/thumbnail.jp

    Military Innovation in the Third Age of U.S. Unmanned Aviation, 1991–2015

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    Military innovation studies have largely relied on monocausal accounts—rationalism, institutionalism, or culture—to explain technologically innovative and adaptive outcomes in defense organizations. None of these perspectives alone provided a compelling explanation for the adoption outcomes of unmanned aerial vehicles (UAVs) in the U.S. military from 1991 to 2015. Two questions motivated this research: Why, despite abundant material resources, mature technology, and operational need, are the most-capable UAVs not in the inventory across the services? What accounts for variations and patterns in UAV innovation adoption? The study selected ten UAV program episodes from the Air Force and Navy, categorized as high-, medium-, and low-end cases, for within-case and cross-case analysis. Primary and secondary sources, plus interviews, enabled process tracing across episodes. The results showed a pattern of adoption or rejection based on a logic-of-utility effectiveness and consistent resource availability: a military problem to solve, and a capability gap in threats or tasks and consistent monetary capacity; furthermore, ideational factors strengthened or weakened adoption. In conclusion, the study undermines single-perspective arguments as sole determinants of innovation, reveals that military culture is not monolithic in determining outcomes, and demonstrates that civil-military relationships no longer operate where civilian leaders hold inordinate sway over military institutions.Lieutenant Colonel, United States Air ForceApproved for public release; distribution is unlimited

    Space-Air-Ground Integrated 6G Wireless Communication Networks: A Review of Antenna Technologies and Application Scenarios

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    A review of technological solutions and advances in the framework of a Vertical Heterogeneous Network (VHetNet) integrating satellite, airborne and terrestrial networks is presented. The disruptive features and challenges offered by a fruitful cooperation among these segments within a ubiquitous and seamless wireless connectivity are described. The available technologies and the key research directions for achieving global wireless coverage by considering all these layers are thoroughly discussed. Emphasis is placed on the available antenna systems in satellite, airborne and ground layers by highlighting strengths and weakness and by providing some interesting trends in research. A summary of the most suitable applicative scenarios for future 6G wireless communications are finally illustrated
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