Autonomous Surface Vessel Positioning for Instrumented Cables
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Solution Overview
Problem
Current methods for accurately positioning control devices along instrumented cables in seawater are inefficient due to high equipment and personnel requirements, positional deviations caused by currents and salinity, and the need for extensive acoustic triangulation and transponder systems, which result in high operational complexity and costs.
Innovation Solution
An autonomous surface vessel equipped with GPS, acoustic communication, and propulsion systems that can move independently to position control devices with high accuracy by using directive modulated acoustic signals and differential GPS corrections, allowing for precise positioning and simplified maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic triangulation with multiple transponders and following vessels is used, then positioning accuracy is improved, but device complexity and operational costs increase significantly
Solution Approach 1:
The invention extracts the positioning function from the control device and implements it on a separate autonomous surface vessel. This eliminates the need for multiple transponders distributed along the cable and multiple following vessels, as only one autonomous vessel with transponder is needed to determine positions of all control devices through acoustic signals.
Solution Approach 2:
The autonomous surface vessel serves multiple functions: it positions itself using GPS, communicates acoustically with all control devices along the cable, determines their positions through triangulation, and performs maintenance operations. This single multi-functional vessel replaces the entire fleet of following vessels and distributed transponder system.
2Measurement precision
If transponders are arranged in the instrumented cable, then positioning capability is provided, but the system becomes vulnerable to cable leakage and requires extensive equipment
Solution Approach 1:
The transponder function is extracted from the instrumented cable and relocated to an autonomous surface vessel. This separation eliminates the vulnerability of cable-integrated transponders to cable leakage and damage, while maintaining the ability to communicate acoustically with control devices.
Solution Approach 2:
The autonomous surface vessel acts as an intermediary between the GPS satellite system and the control devices. It receives GPS positioning data, processes acoustic signals from control devices, and determines their positions without requiring the cable itself to contain positioning electronics.
3Use of energy by moving object
If a towed surface vessel with GPS is used, then positioning data can be obtained, but positional deviation occurs due to currents and line drag
Solution Approach 1:
The autonomous surface vessel is designed to be autonomous rather than towed, allowing it to dynamically position itself directly above or near control devices using its own propulsion system. This eliminates the positional deviation caused by towing line drag and currents that affect towed vessels.
Solution Approach 2:
The autonomous surface vessel performs self-positioning using GPS and own propulsion without requiring external towing. It can independently navigate to and maintain positions near control devices, eliminating dependence on the survey vessel's towing operations and reducing positional errors.
4Productivity
If multiple surface vessels are used for positioning, then all control devices can be positioned simultaneously, but operational complexity and costs increase
Solution Approach 1:
A single autonomous surface vessel is designed to serve all control devices along the entire instrumented cable through acoustic communication. It can sequentially or simultaneously determine positions of multiple control devices, eliminating the need for multiple vessels while maintaining comprehensive coverage.
Solution Approach 2:
The mechanical system of multiple physical vessels is replaced with an acoustic communication system. The single autonomous vessel uses acoustic signals to interact with all control devices along the cable, allowing one vessel to perform the work that would otherwise require multiple vessels.
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
This method achieves accurate positioning of control devices with centimeter-level precision, reduces operational complexity, and simplifies maintenance by using a single surface vessel for all control devices, minimizing positional deviations and equipment needs.
Implementation Method 1
an acoustic element for communication with control devices provided with an acoustic element
Implementation Method 2
an autonomous surface vessel provided with a Global Positioning System (GPS) for accurate self-positioning
Data Source
AI summary
Method and system for high-accurate position determination of control devices arranged in connection with instrumented cables towed behind a survey vessel by at least one autonomous surface vessel provided with acoustic communication means, where the control devices are provided with acoustic elements, and where the acoustic communication means and acoustic elements are used for accurate positioning of the surface vessel above the control device.