Indoor Location via Earth Magnetic Field Map Segmentation
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Solution Overview
Problem
Existing indoor positioning systems face challenges in accurately locating users within buildings due to the lack of satellite coverage for GPS and the inefficiencies of RF-based location discovery methods, which often result in poor accuracy and require expensive equipment.
Innovation Solution
The use of Earth's magnetic field (EMF) for location tracking, combined with a non-magnetic field based location discovery system to provide a location estimate, narrowing the search space and improving the efficiency of EMF-based location discovery by selecting a part of the EMF map based on the non-magnetic field estimate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS satellite based positioning is used, then outdoor location accuracy is improved, but indoor location tracking fails due to lack of satellite coverage
Solution Approach 1:
The patent introduces Earth's magnetic field as an intermediary positioning mechanism that operates independently of satellite signals. Magnetic field sensors detect local magnetic field characteristics to determine position indoors, while GPS continues to provide positioning outdoors, creating a seamless transition between environments without requiring satellite coverage indoors.
2Adaptability or versatility
If RF based location discovery is used indoors, then location tracking is enabled, but accuracy deteriorates and expensive equipment is required
Solution Approach 1:
The patent replaces complex RF-based positioning infrastructure with a simpler magnetic field sensing approach. Instead of deploying expensive RF base stations and complex signal processing systems, the solution uses readily available magnetic field sensors to detect Earth's magnetic field characteristics, achieving accurate indoor positioning with minimal infrastructure.
Solution Approach 2:
The system utilizes Earth's magnetic field as a naturally occurring positioning resource that requires no artificial infrastructure. The magnetic field environment itself provides the positioning information through its unique local characteristics, eliminating the need for deployed transmitters, receivers, or complex networking equipment.
3Measurement precision
If full EMF map search is performed for location discovery, then location accuracy is improved, but computational complexity increases and processing time extends
Solution Approach 1:
The patent divides the comprehensive EMF map into smaller spatial regions or zones. Instead of searching the entire building's magnetic field map, the system segments the search space into manageable portions, reducing computational complexity while maintaining positioning accuracy within each segment.
Solution Approach 2:
The system performs preliminary coarse positioning using non-EMF methods (such as RFID, WiFi, or other sensors) to identify a candidate region before conducting detailed EMF-based refinement. This preliminary action narrows down the search space, allowing the computationally intensive EMF map matching to operate on a smaller, more manageable subset of the full map.
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 and speed of indoor location tracking by utilizing EMF variations specific to building materials and reducing computational complexity, allowing for faster convergence to the correct location hypothesis, especially in emergency situations like enhanced 911 services.
Implementation Method 1
a positioning technique utilizing Earth's magnetic fields (EMF) indoors has been developed as one possible option for indoor location discovery. This type of location discovery applies, for example, a magnetic field strength measured by a positioning device.
Data Source
AI summary
There is provided an apparatus, wherein the apparatus is caused to acquire a location estimate of a positioning device that is to determine its location inside a building, wherein the location estimate is acquired on the basis of an indoor non-magnetic field based location discovery system; access an indoor Earth's magnetic field, EMF, map of plurality of buildings, wherein the indoor EMF map represents at least one of magnitude and direction of the Earth's magnetic field affected by the local structures of a corresponding building; and select a part of the indoor EMF map on the basis of the location estimate of the positioning device, wherein the selected part of the indoor magnetic field map includes the indoor EMF map for the area in which the positioning device currently is.