91,461 research outputs found

    Vessel Collision Avoidance System (VCAS) Based on AIS Data

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    In Indonesia, Maritime transportation delivers more than 71% of 96% to International trade in the world. It is a huge contribution to Indonesian economy. But, it is in contrary in the matter of safety. Based on National Transportation Safety Committee, there are 31 marine accidents, and around 25% of them is ship collisions which caused by human error. Accordingly, the research proposes a design of Vessel Collision Avoidance System (VCAS) based on AIS data as the input of vessel identification trajectory by using Fast Patrol Boat. As the result, this paper simulates Fast Patrol Boat maneuvering to prevent collision with another vessel

    A collision avoidance system for a spaceplane manipulator arm

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    Part of the activity in the area of collision avoidance related to the Hermes spaceplane is reported. A collision avoidance software system which was defined, developed and implemented in this project is presented. It computes the intersection between the solids representing the arm, the payload, and the objects. It is feasible with respect to the resources available on board, considering its performance

    An Experimental Study on Pitch Compensation in Pedestrian-Protection Systems for Collision Avoidance and Mitigation

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    This paper describes an improved stereovision system for the anticipated detection of car-to-pedestrian accidents. An improvement of the previous versions of the pedestrian-detection system is achieved by compensation of the camera's pitch angle, since it results in higher accuracy in the location of the ground plane and more accurate depth measurements. The system has been mounted on two different prototype cars, and several real collision-avoidance and collision-mitigation experiments have been carried out in private circuits using actors and dummies, which represents one of the main contributions of this paper. Collision avoidance is carried out by means of deceleration strategies whenever the accident is avoidable. Likewise, collision mitigation is accomplished by triggering an active hood system

    Improved orbit predictions using two-line elements

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    The density of orbital space debris constitutes an increasing environmental challenge. There are three ways to alleviate the problem: debris mitigation, debris removal and collision avoidance. This paper addresses collision avoidance, by describing a method that contributes to achieving a requisite increase in orbit prediction accuracy. Batch least-squares differential correction is applied to the publicly available two-line element (TLE) catalog of space objects. Using a high-precision numerical propagator, we fit an orbit to state vectors derived from successive TLEs. We then propagate the fitted orbit further forward in time. These predictions are compared to precision ephemeris data derived from the International Laser Ranging Service (ILRS) for several satellites, including objects in the congested sun-synchronous orbital region. The method leads to a predicted range error that increases at a typical rate of 100 meters per day, approximately a 10-fold improvement over TLE's propagated with their associated analytic propagator (SGP4). Corresponding improvements for debris trajectories could potentially provide initial conjunction analysis sufficiently accurate for an operationally viable collision avoidance system. We discuss additional optimization and the computational requirements for applying all-on-all conjunction analysis to the whole TLE catalog, present and near future. Finally, we outline a scheme for debris-debris collision avoidance that may become practicable given these developments.Comment: Submitted to Advances in Space Research. 13 pages, 4 figure
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