Magnetic Parameter-Based Indoor Localization via Segmented Path Matching
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Solution Overview
Problem
Indoor navigation systems face challenges in achieving seamless and accurate positioning without satellite-based navigation, particularly in enclosed spaces, due to limitations in magnetic field data sensitivity and the difficulty of matching magnetic signals to reference databases in real-time, given the exponential number of possible matches.
Innovation Solution
A method and system utilizing magnetic parameter measurements as a primary source for localization, initializing mobile device positioning by comparing series of consecutive measurements to reference data, and using a 'best first' searching approach to efficiently match magnetic signals with pre-calibrated reference segments, thereby reducing computational complexity and memory constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If magnetic field data is used for indoor positioning, then positioning capability is provided in enclosed spaces, but measurement precision deteriorates due to limited sensitivity and difficulty in matching magnetic signals to reference databases
Solution Approach 1:
The patent divides the indoor navigation area into multiple path segments with associated magnetic parameter measurements. Each segment is processed independently, and the system matches consecutive segments based on magnetic parameter sequences rather than attempting to match individual signals. This segmentation approach reduces the complexity of matching and improves overall positioning accuracy.
Solution Approach 2:
The system performs preliminary calibration by collecting and storing magnetic parameter measurements at known locations along path segments before actual navigation occurs. This pre-built reference database of magnetic parameters for each segment enables accurate real-time positioning without needing to match signals to a complete reference database, thereby improving measurement precision.
2Productivity
If real-time matching of magnetic signals to reference database is performed, then localization is achieved, but device complexity increases due to exponential number of possible matches
Solution Approach 1:
The patent segments the navigation path into discrete path segments, each with associated magnetic parameter measurements. The system matches consecutive segments based on magnetic parameter sequences rather than attempting to match individual signals to all possible references. This segmentation reduces the matching problem from exponential complexity to linear processing of sequential segments.
Solution Approach 2:
Instead of matching against the complete reference database (excessive action), the system matches against a curated set of path segments with known magnetic parameters (partial action). This selective matching approach maintains sufficient accuracy while dramatically reducing computational complexity and processing requirements.
3Measurement precision
If magnetic parameter measurements are used as primary localization source, then positioning accuracy is improved, but device complexity increases due to initialization requirements and processing constraints
Solution Approach 1:
The system performs preliminary calibration by collecting and storing magnetic parameter measurements at known locations along path segments before actual navigation occurs. This pre-built reference database of magnetic parameters for each segment enables accurate real-time positioning without needing complex initialization procedures, thereby improving accuracy while managing device complexity.
Solution Approach 2:
By dividing the navigation area into path segments with stored magnetic parameters, the system transforms the complex initialization problem into a simpler segment-matching problem. Each segment is processed independently with pre-stored reference data, reducing the computational burden during actual positioning operations.
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 meter-level positioning accuracy and efficient real-time localization within indoor areas by leveraging magnetic measurements, even when other absolute signals like GPS are limited, and addresses restrictions on WiFi scans in mobile device operating systems.
Implementation Method 1
A magnetic field parameter measurement at a first location within an indoor area may include a magnetic field strength, a magnetic dip angle, and/or at least one of an x, y, or z magnetic field vector component
Data Source
AI summary
A method and system of magnetic parameter based mobile device localization. The method comprises obtaining a predetermined number of magnetic parameter measurements corresponding to a plurality of path segments in an indoor path traversed by a mobile device. Based on accessing a reference database associated with the indoor path, a set of reference segments having a magnetic parameter measurement matching a first magnetic parameter measurement may be identified. In accordance with the identified set of reference segments, a set of alternative trajectories of the mobile device are identified. From the set of alternative trajectories, a current alternative trajectory of the mobile device with a maximum match to the first magnetic parameter measurement may be determined. The current alternative trajectory may be iteratively extended to determine a final alternative trajectory matching the predetermined number of magnetic parameter measurements, the mobile device being localized in accordance with the final alternative trajectory.