Indoor Magnetic Field Sequence Comparison for Relative Movement Tracking
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Solution Overview
Problem
Existing indoor location tracking methods, such as RF-based and GPS, face challenges in accuracy and equipment costs when used indoors, and the utilization of Earth's magnetic field (EMF) requires a pre-existing magnetic field map for effective tracking, which is not always available.
Innovation Solution
An apparatus and method utilizing a processor to acquire and compare indoor magnetic field vectors from multiple portable devices, generating indoor magnetic field sequences to determine relative movements without the need for a pre-existing magnetic field map, by using magnetometers to measure and compare the magnitude and direction of the EMF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RF-based tracking is used indoors, then location tracking can be performed, but accuracy and equipment costs are compromised
Solution Approach 1:
The patent replaces RF-based tracking systems with a magnetic field-based tracking system. Instead of using complex RF infrastructure (base stations, access points), the invention uses magnetometers in portable devices to measure Earth's magnetic field vectors. This substitution eliminates the need for expensive indoor RF infrastructure while maintaining tracking capability through comparison of magnetic field sequences.
2Measurement precision
If Earth's magnetic field is used for tracking, then location discovery can be performed, but a pre-existing magnetic field map is required
Solution Approach 1:
The patent eliminates the need for preliminary magnetic field mapping by performing relative movement determination directly from magnetic field measurements. Instead of pre-mapping the entire indoor environment, the system generates magnetic field sequences on-demand from portable devices and compares them to determine relative movements. This on-demand approach removes the complex preliminary mapping step while maintaining tracking accuracy.
Solution Approach 2:
The patent creates magnetic field sequences that represent the magnetic field environment without requiring a complete pre-existing map. By generating sequences from actual device measurements and comparing these sequences, the system effectively copies or replicates the necessary spatial information locally, eliminating dependence on comprehensive pre-mapped data.
3Loss of information
If magnetic field vectors are measured and compared, then relative movement information can be obtained, but computational processing is required
Solution Approach 1:
The patent extracts only the essential information needed for relative movement determination from the magnetic field measurements. Instead of processing complete magnetic field maps or all measurement data, the system generates compact magnetic field sequences and compares key features between sequences. This extraction approach obtains necessary movement information while minimizing computational requirements.
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 cost-effective tracking of relative movements indoors by generating and comparing indoor magnetic field sequences, allowing for the detection of similar or different paths and speeds of portable devices, even without a pre-existing magnetic field map, thereby improving location discovery and tracking accuracy.
Implementation Method 1
acquire information indicating first indoor magnetic field vectors measured by a first portable device inside a building
Data Source
AI summary
An apparatus caused at least to acquire information indicating first indoor magnetic field vectors measured by a first portable device inside a building; generate a first indoor magnetic field sequence, IMFS, on the basis of the first indoor magnetic field vectors; acquire information indicating second indoor magnetic field vectors measured by a second portable device inside the building; generate a second IMFS on the basis of the second indoor magnetic field vectors, wherein the first and the second IMFSs represent at least one of the magnitude and the direction of the Earth's magnetic field; perform a comparison between at least part of the first IMFS and at least part of the second IMFS; and acquire information on the relative movement of the first portable device with respect to the second portable device inside the building on the basis of the comparison result.