Ultrasonic Vessel Speed Measurement at a Disturbance-Minimizing Depth
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Solution Overview
Problem
Existing vessel speed measurement methods fail to accurately determine the speed through water of a vessel due to disturbances such as wake, leading to inaccuracies in fuel consumption calculations.
Innovation Solution
A vessel speed measurement device and method that identifies a target depth where the vertical speed through water is substantially zero, using a transducer array to transmit and receive ultrasonic waves, and calculates the horizontal speed through water relative to this depth, thereby minimizing the influence of disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow velocities are calculated for multiple depths based on frequency difference, then measurement precision is improved, but the measurement may still be affected by disturbances such as wake
Solution Approach 1:
The patent segments the water column into multiple depth layers and calculates flow velocities for each layer independently. By dividing the measurement space vertically, the system can identify which depth layer is least affected by surface disturbances like wake, thereby improving measurement precision while avoiding harmful factors.
Solution Approach 2:
The patent transitions from measuring speed at a single depth to measuring speeds across multiple depth dimensions. By analyzing the vertical distribution of flow velocities, the system can identify the depth layer where the rate of change is minimal, indicating the layer least affected by surface disturbances, thus resolving the contradiction between precision and disturbance influence.
2Measurement precision
If the speed at a depth with minimal rate of change is selected, then measurement accuracy is improved, but the method does not determine whether this depth is affected by disturbances
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the rate of change of flow velocities across depth layers. By using this feedback information, the system can dynamically identify the depth layer with minimal rate of change and select it for speed through water measurement, ensuring both accuracy and reliability by confirming the layer is least affected by disturbances.
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 measures the speed through water of a vessel in the horizontal direction, unaffected by disturbances like wake, by averaging vertical speed fluctuations and maintaining a high signal-to-noise ratio, ensuring precise fuel consumption calculations.
Implementation Method 1
the frequency of the reflected wave varies from the frequency at the time of transmission due to Doppler effect depending on the vessel speed
Implementation Method 2
a transducer having a transducer array transmits ultrasonic waves into the water and receives reflected waves of the ultrasonic waves
Data Source
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AI summary
The vessel speed measurement device (1) includes a transducer (20) that transmits ultrasonic waves into water and receives reflected waves of ultrasonic waves, and a signal processing circuit (110) that calculates the speed through water of the vessel on which the transducer (20) is installed, based on the reception signal output from the transducer (20). A target depth at which the speed through water in the vertical direction is substantially zero is identified based on the reception signal. The speed through water in the horizontal direction is acquired with respect to the target depth as the speed through water.