Magnetic Marker Detection Using Gradient Filtering
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Solution Overview
Problem
Conventional magnetic marker detection systems for vehicles face reliability issues due to disturbance magnetism from structures like bridges and tunnels, which interfere with the detection of magnetic markers on roads.
Innovation Solution
A magnetic marker detection method using multiple magnetic sensors to generate magnetic gradients and apply filter processing to suppress low-frequency components, improving detection reliability by differentiating between magnetic noise and marker signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic sensors are used to detect magnetic markers on roads, then detection capability is provided, but disturbance magnetism from large structures like bridges and tunnels degrades detection reliability
Solution Approach 1:
The patent divides the road surface into segments by placing multiple magnetic markers at specific intervals. Each marker is detected independently by magnetic sensors on vehicles, allowing the system to distinguish between small localized marker signals and large-scale disturbance magnetism from structures like bridges and tunnels. The segmentation of detection targets enables reliable identification of individual markers despite environmental magnetic interference.
2Measurement precision
If multiple magnetic sensors are deployed to improve detection accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent employs magnetic sensors with different sensitivity characteristics positioned at specific locations on the vehicle. Each sensor is optimized for detecting magnetic gradients in its local region, and the system processes each sensor's output independently through gradient calculation. This local quality approach allows high measurement precision through multiple sensors while managing complexity by assigning specific detection roles to each sensor rather than requiring all sensors to perform all functions.
Solution Approach 2:
The patent calculates magnetic gradients by analyzing differences in magnetic field measurements across multiple sensors in space. By transforming the detection problem from measuring absolute magnetic field strength to measuring spatial gradients (differences between sensor readings), the system achieves higher precision in detecting small magnetic markers. This dimensional transformation from scalar field measurement to gradient vector measurement enhances detection accuracy while the gradient calculation naturally filters out large-scale uniform disturbance magnetism.
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
The method effectively enhances the reliability of detecting magnetic markers by removing disturbance magnetism from larger sources, allowing for accurate identification of markers despite interference from structures like bridges and tunnels.
Implementation Method 1
a magnetic sensor... magnetic measurement values acquired in a same measurement period by two or more magnetic sensors
Data Source
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AI summary
Provided is a magnetic marker detection method with high detection reliability. The magnetic marker detection method for detecting a magnetic marker (10) laid on a road while a vehicle (5) having a plurality of, at least two or more, magnetic sensors attached thereto is travelling includes a gradient generating process of generating a first magnetic gradient, which is a difference between magnetic measurement values of two magnetic sensors and a filter processing process of generating a filter output value by performing filter processing by a high-pass filter as to a change of the first magnetic gradient in a travelling direction of the vehicle. The magnetic marker (10) is detected by an arithmetic operation process regarding the filter output value.