Speed Sensor Calibration via Dynamic Velocity Comparison
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Solution Overview
Problem
Conventional speed sensors for mobile structures face challenges in accurately calibrating speed through a medium (STM) due to variations in medium flow and structural orientation, leading to unreliable transfer of calibration between different mobile structures, even with identical sensors, and are complicated by currents in the environmental medium.
Innovation Solution
A system and method for STM sensor calibration that includes a logic device, memory, sensors, actuators, and modules to interface with a mobile structure, using time series of estimated STM and speed over ground (SOG) velocities to determine an STM sensor calibration, incorporating orientation and position sensors to adjust steering and propulsion systems for accurate calibration without requiring the mobile structure to stop or user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional speed sensors are used to measure speed through medium (STM), then the sensor provides speed measurements, but the calibration between STM and speed over ground (SOG) is unreliable due to variations in medium flow, structural orientation, and currents
Solution Approach 1:
The system continuously compares STM measurements from the speed sensor with SOG measurements from the GNSS receiver, using this feedback loop to dynamically determine and apply calibration factors that compensate for medium flow variations, structural orientation changes, and currents, thereby resolving the contradiction between measurement precision and calibration reliability
Solution Approach 2:
The system changes the calibration parameters dynamically based on real-time conditions by determining calibration factors from the relationship between STM and SOG velocities under varying operational conditions, allowing the calibration to adapt to different medium flow patterns, orientations, and current conditions rather than using fixed calibration values
2Measurement precision
If calibration is performed for one mobile structure, then that structure achieves accurate STM measurements, but the calibration cannot be reliably transferred to other mobile structures even with identical sensors
Solution Approach 1:
Each mobile structure performs its own calibration by autonomously determining calibration factors from its own STM and SOG measurements, eliminating the need to transfer calibration data between structures. The system self-calibrates based on its specific characteristics, medium conditions, and operational parameters, making each calibration structure-specific and reliably accurate for that particular mobile structure
3Measurement precision
If the mobile structure stops to perform calibration, then calibration accuracy can be improved by eliminating motion-related variables, but this reduces productivity and operational efficiency
Solution Approach 1:
The calibration system is designed to operate dynamically during normal mobile structure operation rather than requiring static calibration. The system continuously adapts calibration factors based on real-time STM and SOG measurements taken during various maneuvers and operational conditions, maintaining calibration accuracy while preserving full operational productivity and efficiency
4Ease of manufacture
If manual user intervention is required for calibration, then calibration can be performed with simple equipment, but this increases operational complexity and time requirements
Solution Approach 1:
The calibration system automatically determines calibration factors by processing STM measurements from the speed sensor and SOG measurements from the GNSS receiver without requiring manual user intervention. The system self-calibrates through automated algorithms that analyze the relationship between the two velocity measurements and compute appropriate calibration factors, greatly simplifying the operational process while maintaining calibration accuracy
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 reliable and accurate STM sensor calibration in the presence of unmeasured medium currents, characterizing localized currents for improved navigation, reducing calibration errors typically seen in watercraft, such as sailboats, by minimizing medium current variance across dynamic maneuvers.
Implementation Method 1
a position sensor configured to provide an absolute position and/or a Doppler-derived velocity of the mobile structure
Data Source
AI summary
Techniques are disclosed for systems and methods to provide speed through medium (STM) sensor calibration for mobile structures. An STM sensor calibration system includes a logic device configured to communicate with an STM sensor, an orientation sensor, and a position sensor for a mobile structure. The logic device determines a time series of estimated STM velocities and a time series of speed over ground (SOG) velocities during a dynamic maneuver of the mobile structure. The logic device determines an STM sensor calibration associated with the STM sensor based, at least in part, on the estimated STM velocities and the SOG velocities.