Ship Navigation Collision Zones Using Asymmetric Safe Areas
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Solution Overview
Problem
Conventional ship navigation assisting devices calculate collision danger areas based on a polygonal safe navigation area approximating a perfect circle with its center on the own ship, leading to reduced reliability and limited shape flexibility, which affects the accuracy of determining safe and dangerous directions without trial maneuvers.
Innovation Solution
A ship navigation assisting device that calculates a collision danger area by setting a polygonal safe navigation area around a target ship, using sensors and AIS data to determine collision points and connect them to form a collision danger area, allowing for customizable shapes based on target ship type and navigation status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a polygonal safe navigation area approximating a perfect circle with center on own ship is used, then the collision danger area calculation is simple, but the reliability and accuracy of determining safe and dangerous directions is reduced
Solution Approach 1:
The patent applies asymmetry by deviating the center of the safe navigation area from the own ship's position and allowing the polygonal shape to have varying distances from the center to vertices. This asymmetric configuration enables the collision danger area to accurately reflect directional safety characteristics, improving reliability while maintaining manageable calculation complexity through systematic vertex processing.
2Stability of the object's composition
If a polygonal safe navigation area with center on own ship is used, then the shape is symmetric for all directions, but the freedom degree of shape customization is limited
Solution Approach 1:
The patent implements asymmetry by allowing the safe navigation area to have an arbitrary polygonal shape with the center deviated from the own ship position. The vertices can be positioned at different distances from the center, enabling customization for different navigation scenarios while maintaining computational tractability through structured calculation methods.
3Adaptability or versatility
If the safe navigation area shape is customized to match actual navigation needs, then the adaptability is improved, but the collision danger area changes according to own ship's orientation reducing reliability
Solution Approach 1:
The patent applies preliminary action by pre-calculating the collision danger area based on the customized safe navigation area shape before the own ship changes orientation. The system determines the collision danger area in advance for the current orientation, allowing operators to plan maneuvers with confidence in the accuracy of the displayed danger zones, thereby maintaining reliability despite shape customization.
Data Source
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AI summary
A ship navigation assisting device includes: an area setter 304 that sets, for a target ship, a polygonal safe navigation area defined by a plurality of vertices and surrounding the target ship; a collision point calculator 305 that calculates, based on a speed of the own ship, a relative position between the own ship and the target ship, and a velocity vector of the target ship, collision points between each of the plurality of vertices constituting the safe navigation area and the own ship; and a collision danger area calculator 306 that connects the plurality of collision points calculated by the collision point calculator 305 to calculate a collision danger area.