Terminal Position Estimation Using Elliptical Magnetic Field Models
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Solution Overview
Problem
Existing terminal position estimation systems using electric waves face reduced accuracy due to non-concentric magnetic field strength distributions caused by the directivity of LF transmission antennas, which affects the precision of estimating the position of communication terminals.
Innovation Solution
A terminal position estimation system that uses multiple transmission antennas and a reception antenna to determine the magnetic field strength, employing an approximate expression that accounts for distance and angle between the antennas and the communication terminal, allowing for more accurate position estimation even with elliptical magnetic field distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional position estimation methods using concentric circle reference intensities are employed, then the system structure remains simple, but the position estimation accuracy deteriorates due to non-concentric magnetic field strength distributions caused by antenna directivity
Solution Approach 1:
The patent changes the reference model from concentric circles to elliptical patterns that match the actual magnetic field distribution. By modifying the reference intensity values and their spatial arrangement to account for antenna directivity effects, the system achieves accurate position estimation without requiring complex hardware modifications. The reference intensities are adjusted to reflect the elliptical field patterns, directly resolving the accuracy issue while maintaining system simplicity.
2Area of stationary object
If multiple transmission antennas are used to improve coverage, then the coverage area increases, but the magnetic field strength distribution becomes non-concentric, reducing position estimation accuracy
Solution Approach 1:
The patent explicitly embraces the asymmetry introduced by multiple transmission antennas by using elliptical reference patterns instead of symmetric concentric circles. The reference intensities are arranged in elliptical patterns that match the actual non-uniform magnetic field distribution created by multiple antennas. This allows the system to maintain both wide coverage and high position estimation accuracy by adapting the reference model to the asymmetric field patterns.
3Ease of operation
If the magnetic field strength distribution is assumed to be concentric for simplification, then the calculation process remains simple, but the position estimation accuracy deteriorates due to actual elliptical field patterns
Solution Approach 1:
The patent modifies the reference intensity parameters to reflect elliptical field patterns while maintaining the same overall calculation framework. The reference intensities are reconfigured to match the elliptical distribution, allowing the system to achieve accurate position estimation without fundamentally changing the calculation process. This approach preserves computational simplicity while correcting the accuracy issue caused by the concentric assumption.
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 approach enhances the accuracy of communication terminal position estimation by using an approximate expression that considers the magnetic field strength distribution, effectively improving position estimation accuracy despite non-concentric field patterns.
Implementation Method 1
a position satisfying an approximate expression for each of the multiple transmission antennas within a predetermined range when estimating the communication terminal position based on the magnetic field strength of the electric wave transmitted from the multiple transmission antennas
Data Source
AI summary
In a terminal position estimation system, a terminal position estimation apparatus, or a terminal position estimation method, an electric wave is received by a reception antenna of a communication terminal and is transmitted from multiple transmission antennas. A communication terminal position is estimated based on a magnetic field strength of the electric wave. When the communication terminal position is estimated, a position satisfying an approximate expression is estimated as the communication terminal position. The approximate expression shows a magnetic field strength distribution and is expressed by two variables of a distance from the multiple transmission antennas to the communication terminal and an angle between an axial direction of the multiple transmission antennas and a direction in which the communication terminal is positioned.