Underwater Positioning via Accelerometer Dead Reckoning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional GPS systems are unable to communicate effectively underwater, making it difficult to track the three-dimensional location of objects submerged in water.
Innovation Solution
A positioning system that includes an accelerometer and a processor, which measures acceleration after submersion to calculate a displacement vector and estimate the underwater position using a geographic coordinate system, allowing for continuous tracking without relying on GPS satellite communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS satellite communication is used for positioning, then positioning accuracy at water level is improved, but positioning capability deteriorates when underwater
Solution Approach 1:
The system dynamically switches between GPS-based positioning and accelerometer-based dead reckoning based on the device's location (above or below water). This dynamic adaptation allows the system to maintain positioning capability across different environments by selecting the appropriate method for each condition.
Solution Approach 2:
The accelerometer serves as an intermediary device that enables continuous positioning tracking when GPS is unavailable underwater. By measuring acceleration and integrating it to calculate displacement, the accelerometer bridges the gap in positioning capability between GPS-capable above-water positions and GPS-incapable underwater positions.
2Loss of information
If GPS device is used for positioning, then three-dimensional location tracking is achieved at water level, but communication with GPS satellite fails underwater
Solution Approach 1:
The system performs preliminary action by continuously measuring acceleration data even when GPS is available, so that when the device transitions underwater and GPS becomes unavailable, the accumulated acceleration data can be immediately used to calculate displacement and maintain continuous location tracking without interruption.
3Productivity
If accelerometer-based dead reckoning is used underwater, then continuous positioning is achieved, but positioning accuracy deteriorates over time due to integration errors
Solution Approach 1:
The system uses feedback by continuously monitoring the device's state and switching between GPS-based positioning (when available and more accurate) and accelerometer-based dead reckoning (when GPS is unavailable). This feedback mechanism allows the system to maintain higher accuracy by relying on GPS when possible while preserving continuous tracking capability when underwater.
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
Enables accurate and continuous tracking of underwater positions, providing a reliable method for objects submerged in water by integrating acceleration measurements with geographic coordinates, orientation, and pressure sensing for precise location determination.
Implementation Method 1
continuously measuring, by the accelerometer, acceleration in the geographic coordinate system for a predetermined time duration counting from an instant when the position system dives into water
Data Source
AI summary
A positioning method includes the steps of: obtaining a first geographic coordinate set of a first geographic position at water level in a geographic coordinate system; after a positioning system dives into water at the first geographic position, measuring acceleration in the geographic coordinate system for a predetermined time duration; calculating a displacement vector of the positioning system during the predetermined time duration; calculating an estimated coordinate set of an underwater position of the positioning system according to the displacement vector and using the first geographic coordinate set as an initial point; and outputting the estimated coordinate set to indicate the underwater position of the positioning system.