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In this paper, we present the development of autonomous navigation capabilities for small cruise boats, and their verification by field experiments in a canal and its surrounding waters. A cruise boat was converted to an autonomous surface vehicle (ASV) by installing various sensors and actuators to enable autonomous navigation. Navigation and perception sensors, such as global positioning system,...
This study addresses the development of algorithms for multiple target detection and tracking in the framework of sensor fusion and its application to autonomous navigation and collision avoidance systems for the unmanned surface vehicle (USV) Aragon. To provide autonomous navigation capabilities, various perception sensors such as radar, lidar, and cameras have been mounted on the USV platform and...
For safe ship navigation, efficient and reliable collision assessment and trajectory estimation are required. This study addresses the problem of collision probability assessment between surface ships considering their maneuver intentions. An extended Kalman filter is used for trajectory estimation, and the collision probability and the probability of intentions are evaluated. The maneuver intention...
This study presents the development of vision-based techniques for autonomous collision avoidance by an unmanned surface ship using an onboard monocular camera. In order to determine the initiation of an evasive maneuver, the range and bearing measurements of each target traffic ship with respect to the observer (e.g., own ship) need to be provided for trajectory estimation. A tracking estimator is...
This study addresses autonomous detection and tracking of a surface ship using a monocular camera mounted on an unmanned surface vehicle (USV). Automatic feature extraction and tracking filter algorithms are used for vision-based detection and tracking in real-time. For target tracking, the bearing and range to the target ship with respect to the own ship are obtained by computer vision techniques...
This paper addresses relative navigation of unmanned surface vehicles (USVs) under marine floating structures where GPS signals are severely deteriorated or not available. An onboard 3D lidar collects point cloud of the structures and planar surfaces of their column structures are detected and used as landmark features in the framework of simultaneous localization and mapping (SLAM). The feasibility...
We have developed monolithic white light emitting diodes (LEDs), which consist of planar planes and nano size hexagonal pyramids structure. The white spectrum is achieved by blue and yellow emissions from the InGaN multi quantum wells (MQWs) on the planar c-planes and on the nano-pyramids, respectively. The color temperature is tuned from 3600K to 6400K by controlling the relative area ratio of c-plane...
We report a white emission from InGaN multi-quantum wells (MQWs) on micro size c-planes and nano size hexagonal pyramids hybrid structure. Despite simultaneous growth, we achieve two different emission peaks of 461 nm and 568 from the MQWs on the c-planes and on the nano-pyramids, respectively. Using the structure, we achieve a white emission spectrum which is close to that of a phosphor-converted...
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