Indoor Magnetic Field Map Generation Using Magnetometer Vectors
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Solution Overview
Problem
Existing indoor positioning systems face challenges in accurately tracking users within buildings due to the lack of satellite coverage for GPS and the limitations of RF-based location discovery, which often result in poor accuracy and require expensive equipment, while using Earth's magnetic fields for tracking is affected by building materials and requires extensive mapping efforts.
Innovation Solution
A method and system for generating an indoor magnetic field map using crowd-sourced data from mobile devices equipped with magnetometers, which measure and transmit Earth's magnetic field vectors and their uncertainty measures, allowing for the creation of a comprehensive and accurate magnetic field map that accounts for reliability and variability across different locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS satellite coverage is used for outdoor positioning, then positioning accuracy is improved, but it cannot work inside buildings due to lack of satellite coverage
Solution Approach 1:
The patent introduces Earth's magnetic field as an intermediary for indoor positioning when GPS is unavailable. Magnetic field sensors in mobile devices measure local magnetic field vectors, which serve as a mediator to determine indoor location by comparing measurements against a pre-built magnetic field map of the building.
2Adaptability or versatility
If RF-based location discovery is used indoors, then indoor positioning is enabled, but accuracy is poor and expensive equipment is required
Solution Approach 1:
The patent replaces expensive RF-based positioning infrastructure with a magnetic field-based system using standard magnetometer sensors already present in mobile devices. This substitution eliminates the need for specialized expensive equipment while achieving comparable or better accuracy through magnetic field vector measurements and mapping.
3Adaptability or versatility
If magnetic field strength measurement is used for indoor tracking, then indoor location discovery is enabled, but several problems arise in generating an accurate magnetic field map
Solution Approach 1:
The patent transitions from using only magnetic field strength (scalar) to using magnetic field vectors (three-dimensional with direction components). This dimensional expansion provides richer spatial information that enables more accurate positioning and simplifies map generation by capturing the full magnetic field characteristics at each location.
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 enables efficient and accurate indoor location tracking by providing a reliable magnetic field map that accounts for uncertainty, allowing for precise user positioning and identifying areas needing further measurement, thereby improving tracking accuracy and reducing equipment costs.
Implementation Method 1
acquiring information indicating a magnetic field vector measured by a magnetometer at a location
Data Source
AI summary
Disclosed is an apparatus caused to acquire information indicating a measured magnetic field vector and information relating to an uncertainty measure of the measured magnetic field vector in at least one known location inside the building, wherein the indicated magnetic field vector represents magnitude and direction of the earth's magnetic field affected by the local structures of the building, and to generate the indoor magnetic field map for at least part of the building on the basis of at least the acquired information and the floor plan.