106,930 research outputs found
A novel cooperative platform design for coupled USV-UAV systems
International audienceThis paper presents a novel cooperative USV-UAV platform to form a powerful combination, which offers foundations for collaborative task executed by the coupled USV-UAV systems. Adjustable buoys and unique carrier deck for the USV are designed to guarantee landing safety and transportation of UAV. The deck of USV is equipped with a series of sensors, and a multi-ultrasonic joint dynamic positioning algorithm is introduced for resolving the positioning problem of the coupled USV-UAV systems. To fulfill effective guidance for the landing operation of UAV, we design a hierarchical landing guide point generation algorithm to obtain a sequence of guide points. By employing the above sequential guide points, high quality paths are planned for the UAV. Cooperative dynamic positioning process of the USV-UAV systems is elucidated, and then UAV can achieve landing on the deck of USV steadily. Our cooperative USV-UAV platform is validated by simulation and water experiments. Index Terms-USV-UAV platform. Multi-ultrasonic joint dynamic positioning algorithm. Hierarchical landing guide point generation algorithm. Cooperative positioning
Positioning Accuracy Improvement via Distributed Location Estimate in Cooperative Vehicular Networks
The development of cooperative vehicle safety (CVS) applications, such as
collision warnings, turning assistants, and speed advisories, etc., has
received great attention in the past few years. Accurate vehicular localization
is essential to enable these applications. In this study, motivated by the
proliferation of the Global Positioning System (GPS) devices, and the
increasing sophistication of wireless communication technologies in vehicular
networks, we propose a distributed location estimate algorithm to improve the
positioning accuracy via cooperative inter-vehicle distance measurement. In
particular, we compute the inter-vehicle distance based on raw GPS pseudorange
measurements, instead of depending on traditional radio-based ranging
techniques, which usually either suffer from high hardware cost or have
inadequate positioning accuracy. In addition, we improve the estimation of the
vehicles' locations only based on the inaccurate GPS fixes, without using any
anchors with known exact locations. The algorithm is decentralized, which
enhances its practicability in highly dynamic vehicular networks. We have
developed a simulation model to evaluate the performance of the proposed
algorithm, and the results demonstrate that the algorithm can significantly
improve the positioning accuracy.Comment: To appear in Proc. of the 15th International IEEE Conference on
Intelligent Transportation Systems (IEEE ITSC'12
Dynamic positioning of beacon vehicles for cooperative underwater navigation
Autonomous Underwater Vehicles (AUVs) are used for an ever increasing range of applications due to the maturing of the technology. Due to the absence of the GPS signal underwater, the correct estimation of its position is a challenge for submerged vehicles. One promising strategy to mitigate this problem is to use a group of AUVs where one or more assume the role of a beacon vehicle which has a very accurate position estimate due to an expensive navigation suite or frequent surfacings. These beacon vehicles broadcast their position and the remaining survey vehicles can use this position information and intra-vehicle ranges to update their position estimate. The effectiveness of this approach strongly depends on the geometry between the beacon vehicles and the survey vehicles. The trajectories of the beacon vehicles should thus be planned with the goal to minimize the position uncertainty of the survey vehicles. We propose a distributed algorithm which dynamically computes the locally optimal position for a beacon vehicle using only information obtained from broadcast communication of the survey vehicles. It does not need prior information about the survey vehicles' trajectory and can be used for any group size of beacon and survey vehicles.United States. Office of Naval Research (Grant N00014-97-1-0202)United States. Office of Naval Research (Grant N00014-05-1-0255)United States. Office of Naval Research (Grant N00014-02-C- 0210)United States. Office of Naval Research (Grant N00014-07-1-1102
Precision Agriculture Research, Special Publication
Citation: Coyne, P., Casey, S., & Milliken, G. (2003). Comparison of Differentially Corrected GPS Sources for Support of Site-Specific Management in Agriculture. Kansas State University. Agricultural Experiment Station and Cooperative Extension Service. Ag. Res. Center, Hays, Kansas.Chapter 1: Static Test. Static assessment of the relative performance of three differential correction sources for global positioning systems (GPS) available to users of precision agriculture technology in the Hays, KS area. Chapter 2: Dynamic Test. Dynamic assessment of three differential correction sources for global positioning systems (GPS) to determine suitability for precision agriculture applications in the vicinity of Hays, KS
Sewage Discharging in a Line: Global Optimization and Grand Cooperation
Players cooperating in a line is a special while essential phenomenon in real
life collaborating activities such as assembly line production, pipeline supply
chain management and other streamlining operational settings. In this paper, we
study the scenario of cooperative sewage discharge with multiple participants
positioning in a line along a river such that the optimization decision and
cooperation strategy are mutually affected by both upstream and downstream
players. We make three main contributions accordingly: Firstly, we formalize
the sewage discharge problem (SDP) for different groups of players, and use
greedy strategy and dynamic programming to design the optimal algorithms to
solve the SDP in polynomial time. Secondly, we show that the cooperative game
defined on sewage discharge problem, referred to as SDG, has a non-empty core
due to its special line-positioning structure. Therefore, a grand stable
cooperation is guaranteed. Furthermore, inspired by the fact that the SDG is
core non-empty while non-convex, we successfully identify a relaxed concept of
convexity -- directional-convexity, which can also serve as a sufficient
condition for a cooperative game having a non-empty core
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