Magnetic Field Reference Point Detection in Rail Networks
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Solution Overview
Problem
The precise creation of magnetic field maps for rail networks is challenging due to the need for accurate detection of reference points without relying on GNSS data, which is not feasible in tunnels and other scenarios.
Innovation Solution
A method for magnetic field-based detection of reference points involves carrying out multiple series of measurements to record local magnetic field signatures, comparing these signatures between measurement series to identify matching reference points, and using this information to enhance the precision of the magnetic field map creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If magnetic field-based methods are used for position determination in tunnels and other GNSS-denied environments, then position determination becomes feasible in these scenarios, but the precision of reference point detection deteriorates due to the inability to rely on GNSS data
Solution Approach 1:
The patent changes the parameter of magnetic field signature comparison by using a sliding window approach that compares magnetic field signatures at different offsets. Instead of requiring exact position matching, the system compares signatures with varying temporal offsets to account for position uncertainties, thereby maintaining detection capability while improving precision in GNSS-denied environments
Solution Approach 2:
The patent applies partial action by comparing only a portion of the magnetic field signature (using a sliding window of limited length) rather than requiring complete signature matching. This allows the system to identify reference points even when only part of the magnetic field pattern is detectable or matches, improving reference point detection precision without requiring full signature correspondence
2Measurement precision
If multiple series of measurements are carried out to create a magnetic field map, then the accuracy of the magnetic field map improves, but the time and complexity of the measurement process increases
Solution Approach 1:
The patent applies preliminary action by pre-processing magnetic field signatures during the first measurement series to create a reference database of signatures with their corresponding positions. This preliminary organization allows subsequent measurement series to quickly compare against the database using efficient sliding window correlation, reducing the time required for processing multiple measurement series while maintaining map accuracy
Solution Approach 2:
The patent segments the magnetic field signature comparison process into manageable portions using a sliding window approach. Instead of comparing entire long-duration signatures, the system divides them into smaller segments and compares them independently, which reduces computational complexity and processing time while maintaining the ability to detect reference points across multiple measurement series
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 allows for reliable and precise detection of reference points, improving the accuracy of magnetic field map creation and enabling position determination for rail vehicles in areas where GNSS is not available.
Implementation Method 1
at each of the reference points the magnetic field is detected using a magnetic field sensor
Data Source
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AI summary
The invention relates to a method for magnetic field-based detection of a reference point when performing multiple series of measurements to create a magnetic field map for a rail network. The method comprises the following steps: A first series of measurements is performed to determine a magnetic field at multiple reference points within a specified section of the rail network. A second series of measurements is performed to determine the magnetic field at multiple reference points within the specified section of the rail network. At each of the reference points, the magnetic field is detected using a magnetic field sensor and the position of the reference point is detected using a position sensor. A local magnetic field signature is recorded at each reference point and stored in a database. Each local magnetic field signature represents the local magnetic field in the area around the reference point.At least one magnetic field signature recorded during the second measurement series is compared with the magnetic field signatures recorded during the first measurement series. Identity between a reference point recorded within the second measurement series and a reference point already recorded in the first measurement series is detected if the magnetic field signature to the reference point from the second measurement series exhibits a minimum similarity to the magnetic field signature to the reference point from the second measurement series.