Ship Lidar Height Calculation for Bridge Clearance Prediction
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Solution Overview
Problem
Existing methods for determining whether a ship can pass under a bridge are inaccurate due to the lack of precise self-position estimation, particularly in the height direction, which is crucial for assessing the ship's highest point height relative to bridge clearance.
Innovation Solution
An information processing device that acquires feature and water surface measurement data using a lidar and map data to calculate the ship's highest point height without relying on self-position estimation, utilizing a ship-mounted lidar to measure bridge and water surface distances, and river map data to determine passage feasibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If self position estimation is used to determine ship height, then navigation automation is improved, but measurement precision deteriorates when accurate height estimation cannot be obtained
Solution Approach 1:
The patent introduces water surface measurement data as an intermediary reference to calculate ship height. Instead of relying solely on self-position estimation, the system uses the distance from the ship to the water surface (measured by lidar) and the water surface height (obtained from map data or calculation) as intermediate values to derive the ship's highest point height, thereby improving measurement precision while maintaining automation
Solution Approach 2:
The patent creates a virtual model of the ship's height by copying and combining multiple data sources: the ship-to-water-surface distance from lidar measurements and the water surface height from map data or calculations. This virtual height model compensates for inaccuracies in direct self-position estimation
2Reliability
If tide level prediction information is used to determine bridge passability, then navigation safety is improved, but reliability deteriorates when actual water level exceeds predicted levels
Solution Approach 1:
The patent implements feedback by continuously measuring the actual water surface height using lidar and comparing it with the predicted tide level. When the actual water level deviates from predictions, the system receives feedback and updates the ship height calculation accordingly, allowing for real-time adjustments to maintain reliable bridge passability determination
Solution Approach 2:
The patent performs preliminary calculation of the ship's highest point height using available data (water surface measurements and map data) before the ship reaches the bridge. This allows advance determination of bridge passability with updated height information, enabling timely route adjustments if the clearance is insufficient
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Accurately calculates the ship's highest point height and predicts bridge clearance, enabling safe navigation by determining if the ship can pass under the bridge, even without precise self-position estimation systems.
Implementation Method 1
a measurement device provided in a ship measures a feature and a water surface
Data Source
AI summary
The controller 13 of the information processing device 1 is configured to acquire measurement data of a feature measured by a lidar 3 provided on a ship and measurement data of a water surface. In addition, the controllers 13 is configured to acquire information regarding a height of the feature from a river map DB 10. Then, the controller 13 is configured to acquire highest point information IH regarding a height of the highest point of the ship from a reference position of the ship. Then, the controller 13 is configured to calculate a ship highest point height based on the measurement data of the feature, the measurement data of the water surface, the information regarding the height of the feature, and the highest point information IH.